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SCIENCE OF ZIKA: THE DNA OF AN EPIDEMIC 

HEARING 

BEFORE THE

COMMITTEE ON SCIENCE, SPACE, AND 

TECHNOLOGY 

HOUSE OF REPRESENTATIVES 

ONE HUNDRED FOURTEENTH CONGRESS 

SECOND SESSION 

May 25, 2016 

Serial No. 114–79 

Printed for the use of the Committee on Science, Space, and Technology 

( 

Available via the World Wide Web: http://science.house.gov 
(II) 

COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY 

HON. LAMAR S. SMITH, Texas, Chair 

FRANK D. LUCAS, Oklahoma 

F. JAMES SENSENBRENNER, JR., 

Wisconsin 

DANA ROHRABACHER, California 

RANDY NEUGEBAUER, Texas 

MICHAEL T. MCCAUL, Texas 

MO BROOKS, Alabama 

RANDY HULTGREN, Illinois 

BILL POSEY, Florida 

THOMAS MASSIE, Kentucky 

JIM BRIDENSTINE, Oklahoma 

RANDY K. WEBER, Texas 

JOHN R. MOOLENAAR, Michigan 

STEVE KNIGHT, California 

BRIAN BABIN, Texas 

BRUCE WESTERMAN, Arkansas 

BARBARA COMSTOCK, Virginia 

GARY PALMER, Alabama 

BARRY LOUDERMILK, Georgia 

RALPH LEE ABRAHAM, Louisiana 

DARIN LAHOOD, Illinois 

EDDIE BERNICE JOHNSON, Texas 

ZOE LOFGREN, California 

DANIEL LIPINSKI, Illinois 

DONNA F. EDWARDS, Maryland 

SUZANNE BONAMICI, Oregon 

ERIC SWALWELL, California 

ALAN GRAYSON, Florida 

AMI BERA, California 

ELIZABETH H. ESTY, Connecticut 

MARC A. VEASEY, Texas 

KATHERINE M. CLARK, Massachusetts 

DON S. BEYER, JR., Virginia 

ED PERLMUTTER, Colorado 

PAUL TONKO, New York 

MARK TAKANO, California 

BILL FOSTER, Illinois 
(III) 

C O N T E N T S 

May 25, 2016 

Page 

Witness List ............................................................................................................. 2 

Hearing Charter ...................................................................................................... 3 

Opening Statements 

Statement by Representative Lamar S. Smith, Chairman, Committee on 

Science, Space, and Technology, U.S. House of Representatives ..................... 4 

Written Statement ............................................................................................ 6 

Statement by Representative Eddie Bernice Johnson, Ranking Member, Committee on Science, Space, and Technology, U.S. House of Representatives .... 8 

Written Statement ............................................................................................ 10 

Witnesses: 

Dr. Kacey Ernst, Associate Professor, Department of Epidemiology and Biostatistics, University of Arizona 

Oral Statement ................................................................................................. 14 

Written Statement ............................................................................................ 17 

Dr. Daniel Neafsey, Associate Director, Genomic Center for Infectious Disease, Broad Institute of MIT and Harvard 

Oral Statement ................................................................................................. 30 

Written Statement ............................................................................................ 32 

Dr. Steven Presley, Professor, Department of Environmental Toxicology, 

Texas Tech University 

Oral Statement ................................................................................................. 38 

Written Statement ............................................................................................ 40 

Mr. Hadyn Parry, Chief Executive Officer, Oxitec 

Oral Statement ................................................................................................. 49 

Written Statement ............................................................................................ 51 

Discussion ................................................................................................................. 64 

Appendix I: Answers to Post-Hearing Questions 

Dr. Kacey Ernst, Associate Professor, Department of Epidemiology and Biostatistics, University of Arizona .......................................................................... 88 

Dr. Daniel Neafsey, Associate Director, Genomic Center for Infectious Disease, Broad Institute of MIT and Harvard ........................................................ 100 

Dr. Steven Presley, Professor, Department of Environmental Toxicology, 

Texas Tech University ......................................................................................... 102 

Mr. Hadyn Parry, Chief Executive Officer, Oxitec ............................................... 105 

(1) 

SCIENCE OF ZIKA: THE DNA OF AN EPIDEMIC 

WEDNESDAY, MAY 25, 2016 

HOUSE OF REPRESENTATIVES, 

COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY, 

Washington, D.C. 

The Committee met, pursuant to other business, at 10:25 a.m., 

in Room 2318 of the Rayburn House Office Building, Hon. Lamar 

Smith [Chairman of the Committee] presiding. 
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Chairman SMITH. The Committee on Science, Space, and Technology will again come to order. 

Without objection, the Chair is authorized to declare recesses of 

the Committee at any time. 

Good morning, and welcome to today’s hearing titled ‘‘The 

Science of Zika: the DNA of an Epidemic.’’ Let me recognize myself 

for five minutes for an opening statement. 

For more than a century, humans have been at war with the 

mosquito. In 1901, a U.S. Army physician named Walter Reed led 

a team in Cuba studying diseases that proved yellow fever was 

transmitted by mosquitoes. 

Since that discovery, governments, scientists, and individuals 

have pursued ways to prevent and control deadly mosquito-borne 

outbreaks. From yellow fever, to dengue fever, to Nile virus, humans are constantly under siege from new mosquito-transmitted 

diseases. 

Today, we will examine the state of science in the most recent 

battle in the war against mosquito-borne disease: the Zika virus. 

While for most people Zika causes only mild illness, the Centers 

for Disease Control and Prevention have found that there is a link 

between Zika infection during a woman’s pregnancy and severe 

birth defects. For some adults there could also be serious neurological impacts. 

Summer is coming and so are the mosquitoes that spread the 

Zika virus. The Gulf Coast of Texas, among other places, has been 

called ground zero for this type of mosquito that carries Zika. 

Zika infections have spread to over 80 countries and territories 

in Latin America and the Caribbean. We have seen local transmission of the virus in U.S. territories. In addition, over 500 people 

in the United States mainland have acquired the Zika virus while 

traveling out of the country. Over 300 of these are pregnant 

women. 

These dangers raise serious questions about the Administration’s 

handling of travel alerts. The CDC has issued level two alerts for 

49 countries and territories, which advise travelers only to ‘‘practice enhanced precautions.’’ They have not issued any level three 

warnings to ‘‘avoid nonessential travel,’’ as they did during the 

Ebola epidemic in West Africa. 

The World Health Organization in February declared Zika a Public Health Emergency of International Concern. Such declaration is 

reserved for a situation that is ‘‘serious, unusual or unexpected, 

carries implications for public health beyond the affected state’s national border, and may require immediate international action.’’ 

Why has the Administration not raised the travel alert level for 

countries with the highest number of Zika infections, such as 

Brazil and Colombia? Is the Administration so worried about attendance at the Olympics in Brazil this summer that they’re willing to endanger American lives by not providing better warnings? 

At the least, pregnant women should be told to avoid nonessential 

travel to Brazil and Colombia. Anything less is putting political 

correctness ahead of the well-being of American women. 

Today I hope that we can gather additional scientific information 

on Zika and the mosquito that spreads it. I also look forward to 
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hearing about research on the best methods for controlling the 

spread of the Zika virus. 

[The prepared statement of Chairman Smith follows:] 
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Chairman SMITH. That concludes my opening statement, and the 

gentlewoman from Texas, Ms. Johnson, the Ranking Member, is 

recognized for her opening statement. 

Ms. JOHNSON. Thank you very much, Mr. Chairman, for holding 

this hearing. 

This morning we are talking about the Zika virus, something 

that has been in the news a lot lately and that we have been debating on the House Floor. 

The most common way that someone becomes infected with the 

Zika virus is by a mosquito bite. The symptoms of the virus may 

include fever, rash, joint pain, and red eyes. These symptoms are 

typically mild, and many people who get infected with the Zika 

virus have no symptoms or do not seek medical treatment. 

Although the Zika virus was first identified in the late 1940s, 

there were no major outbreaks of the Zika virus until 2007. Since 

then, the Zika virus has been reported in almost 70 countries and 

territories, including the major Zika outbreak that is happening in 

Brazil, where more than a million cases have been reported. 

In the United States, local transmission of the Zika virus has 

been reported in several U.S. territories. In particular, Puerto Rico 

is suffering from a large Zika outbreak in which more than 800 

cases have been reported to date. In the continental United States, 

the only Zika cases that have been reported involve people who 

have traveled to places that have a Zika outbreak. But the number 

of those cases is already more than 500, and there is significant 

concern that the continental United States will start seeing locally 

transmitted cases of the Zika virus once we get further into the 

mosquito season. 

Even though my home State of Texas only has 35 travel-associated cases of the Zika virus so far, I have been hearing from a lot 

of concerned constituents about the Zika virus and the potential for 

a Zika outbreak in Texas this summer. 

I would imagine that many of my colleagues on this Committee 

have been hearing from concerned constituents as well. I am 

pleased that we will have more information to pass on to them 

after this hearing. 

What is especially troubling about the Zika virus is that it has 

been associated with several significant health conditions, including birth defects in infants and neurological conditions in adults. 

Most notably, the Zika virus has been linked to microcephaly, a 

birth defect where the brain does not develop during pregnancy or 

after birth. This condition results in significant impairments for 

the baby and can result in death. Brazil has seen thousands of 

these cases. In the United States and territories, hundreds of pregnant women who have been infected with the Zika virus are currently being monitored. Unfortunately, last week the first case of 

microcephaly was reported in Puerto Rico. 

Additionally, the Zika virus has been associated with GuillainBarre syndrome, a disorder where the body’s immune system attacks part of the nervous system. People who have this syndrome 

usually recover, but the syndrome can result in permanent paralysis or death. 

Understandably, people are very concerned about this virus and 

want more information. That is why I am happy we are holding 
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this hearing to learn more about the science behind this disease 

and to hear more about the key research questions. For example, 

how is the virus transmitted from mother to fetus and how is the 

risk to the fetus related to the timing of the mother’s infection? 

Does Zika cause Guillain-Barre syndrome and if so, is there an 

intervention that can prevent this terrible condition? 

We also need to know where the vector mosquitoes live, the incubation period of the virus in the mosquito, and whether the infected female can transmit the virus to her eggs. 

Finally, it is perplexing that the Zika virus was first identified 

in the late 1940s, but we are only seeing major Zika outbreaks 

now. What has changed in the last 70 years to make conditions 

more suitable for the virus to be transmitted? I imagine that the 

rapid increase in human travel has played a large role, but I do 

wonder how much other factors like insecticide resistance and climate change may be playing in the spread of this disease. 

All of these research questions need to be answered as we plan 

effective mosquito control programs and prepare to invest our resources. But traditional mosquito control programs will not be 

enough. 

I am looking forward to hearing from our expert witnesses on 

how emerging technologies that use advanced genetics and biologic 

technologies could help control the Zika virus. 

It is also important to note that to support the necessary research, surveillance, mosquito control, and drug and vaccine development programs that will be needed to control this disease, we 

must ensure that adequate funding is provided. I am hopeful that 

Congress can come together to provide that funding. Time is of the 

essence. And I’m thankful that the experts are here. 

And just before I yield back, Mr. Chairman, I want to take a moment to recognize one of my staff, Kim Montgomery, who is sitting 

beside me now. She’s leaving soon to move to Vienna, Austria. She 

has been an integral part of the staff. Her passion and expertise 

will be greatly missed. I want to thank you for your service and 

wish you luck in your new, exciting chapter in Vienna. 

Thank you, and I yield back, Mr. Chairman. 

[The prepared statement of Ms. Johnson follows:] 
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Chairman SMITH. Thank you, Mrs. Johnson. 

Let me introduce our witnesses, and our first witness today is 

Dr. Kacey Ernst, Associate Professor, Department of Epidemiology 

and Biostatistics at the University of Arizona. Dr. Ernst joined the 

University of Arizona staff in 2008. Her area of specialization is the 

intersection of environment, humans, and mosquito vectors of disease. As an epidemiologist, her role is to work with a highly interdisciplinary team of scientists to integrate information from climatology, entomology, medical anthropology, and ecology across multiple institutions to develop an understanding of the emergence of 

infectious diseases. Dr. Ernst received her master’s in public health 

and doctorate in epidemiology from the University of Michigan. 

We want to thank particularly Dr. Ernst today for being here because in so doing she is missing her daughter Savannah’s graduation from the fifth grade and on to middle school. So tell your 

daughter that we appreciate your good help in trying to help the 

Federal Government, and I hope she’ll excuse you missing that 

graduation. 

Our second witness today is Dr. Daniel Neafsey, Associate Director, Genomic Center for Infectious Disease at the Broad Institute 

of MIT and Harvard. In this role, Dr. Neafsey leads a research 

group studying the DNA of mosquito vectors and the pathogens 

they transmit. He has developed pioneering resources and computational methodologies for genetic studies of mosquitoes and 

mosquito-borne pathogens. Dr. Neafsey received his B.A. from Loyola University in Chicago and his Ph.D. from Harvard University. 

Our next witness, Dr. Steven Presley, will be introduced by the 

gentleman from Texas, Mr. Neugebauer. 

Mr. NEUGEBAUER. Well, thank you, Mr. Chairman. 

Our third witness today is Dr. Steven Presley. He’s a Professor 

in the Department of Environmental Toxicology at Texas Tech University. Dr. Presley’s professional career has focused upon vectorborne infectious diseases with an emphasis on biological threat assessment and countermeasures to protect the population from infectious diseases. He’s published more than 90 scientific and technical papers, co-edited two textbooks, authored and co-authored 11 

book chapters in the fields of biological and chemical countermeasures and diseases of wildlife. He served in the United States 

Navy in the Medical Services Corps and he was an officer for more 

than 12 years before joining the faculty at Texas Tech University 

in 2002. He earned his bachelor of science in animal science from 

Texas Tech University and master of science and doctorate of philosophy in entomology from Oklahoma State. It’s good to have a fellow Red Rider, Dr. Steven Presley, with us today. 

Chairman SMITH. Thank you, Mr. Neugebauer. 

Our last today is Mr. Hadyn Parry, Chief Executive Officer of 

Oxitec, a U.K.-based company pioneering the use of genetic engineering to control insects that spread disease and damage crops. 

During his 15-year career at Zeneca Syngenta, he held various positions including general manager of Zeneca Plant Sciences. Mr. 

Parry also has served as the European Director and Global Head 

of R&D for Advanta, one of the world’s largest seed companies. 

More recently, he was CEO of MNL Pharmaceuticals, a company 

that was focused on pioneering a novel approach to immunology. 
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Mr. Parry received a bachelor of arts in international history and 

politics from the University of Leeds. 

We welcome you all, and Dr. Ernst, we will begin with you. 

TESTIMONY OF DR. KACEY ERNST, 

ASSOCIATE PROFESSOR, 

DEPARTMENT OF EPIDEMIOLOGY 

AND BIOSTATISTICS, 

UNIVERSITY OF ARIZONA 

Dr. ERNEST. Thank you. Thank you, Chairman Smith and Ranking Member Johnson. 

So today I want to give you a little bit of background on the 

Aedes aegypti mosquito. This is the mosquito depicted here. It is 

the primary vector of Zika virus. It’s highly adaptable and highly 

invasive. It’s originally from sub-Saharan Africa but has been widely dispersed across the globe through the mobilization of people 

and goods. 

Aedes aegypti is tightly linked to humans and their activities. It 

prefers to feed on human blood, and lays its eggs in manmade containers in and around homes. One of the reasons why it’s such a 

difficult mosquito to control is because it can exploit even as much 

as one inch of water to go through its entire immature lifecycle. 

It’s a day biter, which means that it primarily feeds in the morning and in the afternoon, which means things like bed nets are not 

as effective as protecting against the diseases that it’s transmitting. 

Not only does this mosquito transmit Zika virus but it is also a 

primary transmitter of yellow fever, dengue, chikungunya, and one 

that you probably haven’t heard of yet, which is called Mayaro 

virus. Next slide, please. 

[Slide.] 

This is the CDC’s recently updated maps of the estimated distribution of Aedes aegypti and Aedes albopictus in the United 

States. Aedes albopictus is a relative of Aedes aegypti, which is 

also capable of transmitting Zika virus, but it can withstand cooler 

temperatures and it is a more generalist feeder. That means that 

it doesn’t feed as preferentially on humans as Aedes aegypti. Its 

role in the current outbreak is not well understood at this time. 

The ranges here are only estimates because many of the jurisdictions in these areas do not have active surveillance for Aedes species. Next slide, please. 

[Slide.] 

The predominant transmission cycle for Zika virus occurs when 

a female Aedes aegypti mosquito bites an infected human. The 

virus goes through a development stage in the mosquito of a currently unknown time period, probably about a week is what we estimate at this time, and that is dependent upon the temperature. 

It would be faster if you have hotter temperatures. This is called 

the extrinsic incubation period. After that time period, the mosquito is capable of transmitting the virus to the next person that 

it bites and then remains capable of transmitting for the duration 

of her life, about two to four weeks. 
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It’s not yet known if the Zika virus can be transmitted through 

vertical transmission. This means that an infected female mosquito 

could transmit the virus to her offspring. If it proves to be true, the 

female Aedes aegypti could emerge infectious from their immature 

aquatic state and be able to infect people the first time that they 

bite, shortening the transmission cycle. It would also mean that 

from season to season, eggs that had over wintered could potentially harbor the virus and it would not need to be reintroduced the 

next season. 

Also depicted in this slide are other transmission modes, which 

would be sexual transmission from a male partner to a female partner, and then of course, the transmission from the mother to the 

fetus. Next slide, please. 

[Slide.] 

In order to create forecasts of when and where transmission of 

Zika may occur, there are many components of the system that 

would need to be understood. We can use weather forecasts to drive 

models of the mosquito because their biology is largely determined 

by weather and climate. As you can see in this rather complex depiction here, at each stage of the mosquito lifecycle, you have influences of both temperature as well as precipitation and manmade 

filling of the habitat. Not each of these links is well defined so we 

use the best knowledge that we have to estimate the relationships 

that you see here. The mosquito component of this model is much 

better understood at this point because Aedes aegypti have been 

studied in the context of dengue and yellow fever for decades. The 

top row, which depicts the human portion of the transmission 

cycle—people who are susceptible, exposed, then infectious and 

then recover from the disease—is the least understood part of this 

cycle. 

It’s also important to note that while this is a theoretical model, 

there are other things that can mitigate this relationship, things 

like vector control, socioeconomic factors, as well as other human 

activities that could alter what would be depicted coming out of a 

model. Next slide, please. 

[Slide.] 

In the work that we recently published, we initiated the process 

of exploring some of these complex factors in 50 cities across the 

United States. What you see on this map is the relative potential 

abundance of Aedes aegypti as projected from a model using average seasonal climate data. On the top circle, you have the average 

potential abundance for January, and on the bottom, the potential 

abundance for July. Some of the areas that have the highest projected abundance coincide with areas where there’s been local outbreaks of dengue and chikungunya viruses already. 

The size of the circle indicates the average number of monthly 

arrivals from the countries where Zika virus was circulating in 

February. The tan shading demonstrates the distribution of where 

actual observations of Aedes aegypti have been made across this 

area. 

The work we published is only a first step towards actual forecasting. We need better surveillance, improved knowledge of the 

virus-mosquito-human interactions, and sustained support for the 

infrastructure and dissemination of forecasts. 
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Thank you. 

[The prepared statement of Ms. Ernst follows:] 
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Chairman SMITH. Thank you, Dr. Ernst. 

And Dr. Neafsey. 

TESTIMONY OF DR. DANIEL NEAFSEY, 

ASSOCIATE DIRECTOR, 

GENOMIC CENTER FOR INFECTIOUS DISEASE, 

BROAD INSTITUTE OF MIT AND HARVARD 

Dr. NEAFSEY. Thank you. So Mr. Chairman, Ranking Member 

Johnson, and Members of the Committee, thank you for holding 

this hearing, and for the opportunity to present today. I also want 

to acknowledge one of the Committee members, Representative 

Clark, an important supporter of the strong research community 

we have in Cambridge, Mass. 

My research group at the Broad Institute in Cambridge uses 

DNA sequencing to understand and control infectious diseases, and 

I’m here today to speak specifically about how DNA sequencing can 

help us to understand and inform the control of Zika transmission. 

We lack fundamental understanding of how the Zika virus moves 

from person to person via Aedes mosquitoes, information that is 

crucial for an effective response to this epidemic. 

Mosquitoes are not flying hypodermic needles that passively 

transmit disease. The successful transmission of mosquito-borne 

disease depends on complex biological and ecological interactions 

between mosquitoes, their human hosts, and the pathogens that 

they transmit. 

Insight into the biology of how Aedes mosquitoes are able to 

spread disease can be gained through sequencing and mapping the 

Aedes genome, or the entirety of its DNA. We know that because 

we have demonstrated this with Anopheles mosquitoes, which 

transmit malaria. 

So I led a project at the Broad Institute recently funded by the 

NIH and involving more than 130 collaborators from 19 countries 

around the world to build genome assemblies or maps of all the 

DNA of 16 different kinds of Anopheles mosquitoes, some of them 

very proficient at transmitting malaria and some of them deficient. 

We learned a lot of things from this project but—if we can advance 

the slide—I will show just one small result. This is a figure that 

we built by comparing the genome maps of these different mosquitoes and identifying those groups of genes that were changing most 

quickly or most slowly between these different mosquitoes. As you 

can see, the most rapidly changing genes at the top of this list in 

red are those genes that we know to influence how mosquitoes 

taste and smell, and we know that there’re important genes in this 

class that determine whether mosquitoes prefer to bite people or 

animals, and a strong preference for biting humans is a very important determinant of disease transmission. 

So close behind those smell and taste genes are genes that provide mosquitoes with an immune system, and we know that variation in these genes can determine whether or not mosquitoes are 

able to transmit pathogens or control infections and not transmit 

them to the next person they bite. 

So no comparable set of genomic research yet exists for Aedes 

mosquitoes despite the fact that they transmit Zika as well as the 
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three other major viral diseases that Dr. Ernst mentioned. Next 

slide, please. 

[Slide.] 

Here’s an image showing the current stage of a recent Aedes 

aegypti mosquito genome map. The map is in approximately 3,700 

pieces despite the fact that this mosquito has only three chromosomes, so the target is three. The original map for Aedes mosquitoes published in 2007 was in about 10 times as many pieces, 

so we’re making progress. 

So as mosquito season begins in the Gulf states and with Zika 

on the doorstep of the United States, we lack foundational resources to pursue DNA-based studies of the biology and transmission of Zika. This resource gap is critical. Infectious disease epidemiology has been transformed by DNA during the last ten years 

into a rich digital information science allowing biologists and public 

health agencies to track the spread of outbreaks over time and 

space and learn about what mosquito and human factors contribute 

to disease spread. We can now tackle emergent infectious diseases 

like Zika using efficient and innovative genetic tools to build databases and situational awareness of diseases, and the scientific community stands ready to develop and apply these tools to the Zika 

epidemic to protect vulnerable populations within our borders and 

around the world. 

One example of that readiness is the Aedes Genome Working 

Group organized just this last January via Twitter by Dr. Leslie 

Vosshall at Rockefeller University. This upstart group’s mission 

has been to produce an improved genome map for Aedes mosquitoes using new sequencing technology that is 10,000 times cheaper 

than the technology available ten years ago. With no central funding but a lot of donated time and resources from a range of academic and industry partners just motivated to improve our capacity 

to respond to Zika, this group has made rapid progress exploring 

a spectrum of new technologies for building an improved genome 

map. 

So with continued support and follow-up research, this map will 

yield knowledge that informs disease-control measures. Examples 

of such measures include insecticide resistance detection and surveillance, mosquito population studies, and genetic modification of 

the mosquito, new tools for which are creating an increasingly direct connection between basic DNA research and control measures. 

The Zika epidemic can become a proving ground for the power 

of new DNA-based resources and epidemiological tools. Taking advantage of rapidly falling costs, we can demonstrate to the world 

how new technologies will let us understand, anticipate and control 

the spread of an epidemic, and we have an obligation to vulnerable 

populations to seize this opportunity. 

So thank you to the Chairman, Ranking Member Johnson, and 

the Committee for your attention, and I’ll be happy to answer any 

questions you may have later in the hearing. 

[The prepared statement of Dr. Neafsey follows:] 
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Chairman SMITH. Thank you, Dr. Neafsey. 

And Dr. Presley. 

TESTIMONY OF DR. STEVEN PRESLEY, PROFESSOR, 

DEPARTMENT OF ENVIRONMENTAL TOXICOLOGY, 

TEXAS TECH UNIVERSITY 

Dr. PRESLEY. Good morning, Mr. Chairman and Committee 

Members. Thank you for the opportunity to address this important 

public health threat. My name is Steve Presley. I’m a medical entomologist and Professor of Environmental Toxicology and the Director of the Biological Threat Research Laboratory at Texas Tech 

University. 

Zika virus, like chikungunya, dengue and yellow fever virus, is 

transmitted to humans through the bite of Aedes aegypti and 

Aedes albopictus. The biology and behavior of these mosquitoes differs significantly from vectors of West Nile virus and other 

arboviruses in the United States, and these differences, those 

unique challenges for controlling them in urban and suburban 

areas. 

Zika virus infection typically causes less than severe illness with 

only about 20 percent of infected individuals reporting symptoms. 

Theoretically, a mosquito taking a blood meal from an asymptomatic but infectious individual could become infected with the 

virus and transmit it to other people being the initial link in establishing local transmission in an area where no Zika virus cases 

have previously been reported. 

Vectors of Zika virus are mainly daytime biters and they prefer 

to be in our houses and offices. They are container breeders, and 

they rest in shaded areas during the heat of the day in the house 

or outdoors under the eaves of the house or in vegetation in the 

yard. 

My lab at Texas Tech is a component of the CDC’s Laboratory 

Response Network, and a certified human diagnostic testing facility. We’re at Texas Department of State Health Services testing lab 

for the Zika virus and other high-consequence infectious diseases. 

Testing for Zika virus is limited to designated laboratories using a 

protocol allowed under the Food and Drug Administration’s Emergency Use Authorization. The real-time RT–PCR assay that we use 

detects and differentiates RNA extracted from dengue, 

chikungunya, and Zika viruses in various bodily fluid samples. 

The Texas Department of State Health Services is coordinating 

an entomology consultation group to develop strategies and identify 

resources relative to controlling the Zika virus vectors. The consultation group is composed of entomologists and public health professionals engaged in mosquito and infectious disease research or 

public health education. Sixty-six percent of Texas counties have no 

records of Aedes aegypti or Aedes albopictus occurrence, and more 

than 200 Texas counties have not conducted mosquito surveillance 

during the last two years. Scientists of the consultation group are 

fielding teams to update distribution maps for these vectors in 

Texas, and there are numerous reports of insecticide resistance in 

Aedes aegypti and Aedes albopictus populations globally where 

they occur. The consultation group is identifying resources to determine insecticide resistance in these vectors throughout Texas. The 
39 

consultation group is drafting Zika prevention information to make 

available to the public through various online and social networking technologies, providing do-it-yourself information to homeowners on how to eliminate mosquitoes on their property using offthe-shelf commercial pesticide products and application equipment. 

The American Mosquito Control Association is developing guidelines for mosquito control by public health agencies and commercial 

entities, emphasizing approaches applicable to the biology and behavior of Aedes aegypti and Aedes albopictus. 

All of the Zika virus cases in the continental United States have 

been attributed to travel-associated exposure with no local transmission confirmed. Conversely, there’re been about 800 locally acquired infections reported in America Samoa, Puerto Rico, and the 

U.S. Virgin Islands, and only three travel-associated cases in those 

areas. This significant difference between locally acquired and travel-associated infectious is due to seasonal and climatic differences 

in most regions. Currently in most regions of the United States, 

these vectors seasonal activity is just now beginning. All efforts 

must be made to stay ahead of peak mosquito activity by immediately implementing comprehensive public health education programs and enhancing vector surveillance and control capacity. 

I am collaborating with two private companies on projects relative to Zika virus. One company provides a comprehensive digital 

outcome support system for healthcare professionals, and the other 

has developed a smartphone-based DNA detection platform that is 

field deployable and does not require laboratory facilities. The device is a real-time PCR thermocycler that attaches to a 

smartphone. Results are provided within 40 to 45 minutes and can 

be tagged with various metadata, synced to a web portal for remote 

access, and we are planning to conduct field experiments in Florida, Puerto Rico and Central and South America to validate the accuracy of the system. 

There is a common realization each time an emerging arthropodborne disease threatens public health, that being regardless of how 

modern medical and scientific technologies advance, protecting the 

public health from vector-borne diseases requires both basic and 

applied understanding of the vector’s biology, behavior, and 

vulnerabilities. 

Thank you for your time. 

[The prepared statement of Dr. Presley follows:] 
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Chairman SMITH. Thank you, Dr. Presley. 

And Mr. Parry. 

TESTIMONY OF MR. HADYN PARRY, 

CHIEF EXECUTIVE OFFICER, OXITEC 

Mr. PARRY. Thank you, Chairman Smith, Ranking Member Johnson, Members of the Committee. Thank you for inviting me to testify today. 

As the Chairman noted, we are facing an unprecedented challenge of mosquito-borne diseases today. Vector controlling the mosquito is actually our first line of defense, and it’s an area we’ve 

sadly neglected over the past decades, and because of this, we have 

seen sharp rises in dengue, we have seen the introduction of 

chikungunya, and now we have the Zika emergency, and I’m sorry 

to say, but current insecticidal products are just not sufficient to 

control this mosquito in the urban environment. 

So at Oxitec, we looked for and developed a new approach, and 

that was to use the mosquito against itself. So we have produced 

a genetically engineered Aedes aegypti strain, which we call LX– 

5138, and it carries two genes. It carries a self-limiting gene and 

a color marker. Now, the way this works is, we release males— 

males don’t bite, they cannot bite—and they go out and they mate 

with females. The offspring will all inherit a copy of the self-limiting gene, and then they die before becoming adults, thereby reducing the wild population, and effectively, it’s a numbers game. If 

we can put more of our males into the environment, the females 

cannot tell the difference and more will mate with our males, the 

offspring will die, and we’ll bring the population crashing down. 

The offspring also inherit this fluorescent marker you can see in 

the slide that you can’t see with the naked eye but you can see 

under a light and a filter, and this provides a track-and-trace-type 

capability so we can see where our mosquitoes go, we can see what 

the effect is that we’re having, and we can moderate the program 

as we go along in real time. 

The releases are made from a truck driven by an operational 

plan, which we work out to make sure we cover the whole town, 

and we have a GPS system that helps us in terms of decision support. 

The efficacy of this approach has actually been quite remarkable. 

In all the outdoor trials we have produced, every single one we 

have reduced the Aedes aegypti population in the urban environment by over 90 percent in about six months, and that is hugely 

more effectively than can be done with insecticides. 

Now, safety and respect for the environment are obviously key 

factors, and again, in stark contrast to insecticides, we are just targeting the one mosquito species that is spreading the disease, so 

this is a species-specific approach. 

Just as important, actually, I’d like to draw two points to your 

attention. Our insects do not persist or stay in the environment. 

The males we release will die. The offspring will die. It’s a matter 

of days they will disappear. And also the marker system means actually that the whole process, the whole control program, is precision and metric-driven. 
50 

I’d also like to stress that in contrast to many other approaches 

that have been muted at the moment in response to Zika, we actually started this in 2002. Our product was developed in 2002 justified at that time by dengue, and it’s all the more necessary now. 

And then we started doing outdoor evaluation in open field trials 

since 2009, so we have a very long body of evidence and data to 

back up both the efficacy and the environmental side. We’ve now 

received national biosafety approval in Brazil, and indeed, the 

World Health Organization has specifically recommended this product for operational use as part of their emergency responses to 

Zika. So these are ready to use now. 

In the United States, the regulatory process is actually still ongoing but we opened a file with the FDA as far back as 2011 in order 

to conduct a small field trial, which is actually a very necessary 

part of the regulatory requirements. The FDA recently published a 

finding of no significant impact, but while we’re waiting for the 

final review and final decision, we’re not able to move forward. But 

in that same time frame, 2011 to today, in Brazil, we have filed 

similar applications. We’ve carried out several field trials. We’ve 

formed a company. We built a factory. We’ve got national biosafety 

release, and we’re now in operational use. 

Members of the Committee, I don’t think time is on our side with 

Zika, and I think the utmost urgency is required in every area. I’ve 

come from Puerto Rico, and we could have a catastrophe on our 

hands if we’re not careful. At any one time, there are 28,000 

women pregnant, and that is a very salutary thought when you 

think that summer is coming up and we have active disease transmission. 

So in view of that urgent health need, we’d urge your support actually to give the FDA all your support and encouragement so they 

can expedite approval of our application, and I would also urge consideration of an emergency use authorization actually, which is 

used sometimes to bring forward new medication or diagnostics, 

but I think the fact that we have such an urgent and pressing need 

means the FDA needs more tools at its disposal in order to help 

protect Americans. We want to make this technology available in 

the coming months rather than the coming years. 

Thank you very much. 

[The prepared statement of Mr. Parry follows:] 
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Chairman SMITH. Thank you, Mr. Parry. 

Let me direct my first question to Dr. Presley, Dr. Ernst and Dr. 

Neafsey, and let me say initially, though, that we have two countries, Brazil and Colombia, where there are thousands of cases of 

individuals with the symptoms from Zika virus. We know that for 

every one who has a symptom, there are 20 others who are infected. We also know that over 99 percent of those in the United 

States who have become infected and have the symptoms contracted the Zika virus because of travel outside the country. So my 

question is this: Don’t you feel that the Federal Government should 

issue a travel advisory that says that at the least, pregnant women 

and perhaps others, should avoid all nonessential travel to those 

two countries and perhaps others? Dr. Presley? 

Dr. PRESLEY. Yes, sir, Mr. Chairman. I believe that the potential 

for people to travel to countries where the Zika virus transmission 

is actually occurring and then bring back an infection, they may be 

asymptomatic, but I believe stricter travel restrictions or advisories 

should be implemented. 

Chairman SMITH. Okay. When you say that we should suggest 

that those traveling from the United States to other countries avoid 

all nonessential travel, are you talking about just women or a 

wider group? 

Dr. PRESLEY. I’m talking about any nonessential travel from the 

standpoint of the few cases of sexual transmission were from male 

partners that came back, and I know at least one of the cases was 

a woman. A partner had become infected. 

Chairman SMITH. So the government should issue a warning that 

says avoid all nonessential travel to Brazil, Colombia, anywhere 

else? 

Dr. PRESLEY. I believe so, sir. 

Chairman SMITH. Okay. Thank you. 

And Dr. Ernst? 

Dr. ERNST. I would say that definitely for pregnant women that 

it would be advisable to have them restrict nonessential travel but 

also to make sure that they understand if they are going to an area 

and they do choose to go to an area, that they look at the geography of the risk. So it is possible that in some of these countries 

where Zika virus is being transmitted that there are high-altitude 

locations and other locations within those countries that do not 

have Zika transmission or even the vector that is present so really 

trying to understand more specifically where they’re going and 

working with their doctor to get advisement on whether or not it 

is important for them to—— 

Chairman SMITH. I think I saw a map, at least of Brazil, perhaps 

of Colombia, that showed over half the country was actually below 

the 6,000-foot altitude, so it seems to me—but you do agree at least 

for pregnant women that there should be an advisory to avoid all 

nonessential travel? 

Dr. ERNST. Correct. 

Chairman SMITH. Okay. Thank you. 

And Dr. Neafsey? 

Dr. NEAFSEY. Sure. I think this question probably falls closer to 

the expertise of my co-panelists, but I think it would be reasonable 

to advise caution, especially for pregnant women who might con-
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sider traveling to a Zika-endemic area. But to echo what Dr. Ernst 

mentioned, beyond geographic considerations and altitude, there 

are also seasonal dynamics that really contribute to Zika transmission, so it’s—— 

Chairman SMITH. What would be the most dangerous time of the 

year to travel? 

Dr. NEAFSEY. Oh, I think the hot, wet time of the year. 

Chairman SMITH. Summer? 

Dr. NEAFSEY. Yes, but I think at this stage it’s very difficult to 

quantify exactly what that represents. 

Chairman SMITH. Okay. Thank you. 

Second question to Dr. Presley and Mr. Parry, and that is, what 

are the best preventative measures that we in the United States 

could take to try to avoid contracting the virus? 

Dr. PRESLEY. Because the biology and behavior of these vectors 

is completely different than the mosquito vectors of West Nile virus 

or other arboviruses, the immediate concern or the immediate action is, I believe prevention from the standpoint of educating the 

public. These mosquitoes are called backyard mosquitoes for a reason because they like to live around people and in their yards, so 

the pesticide application technologies and approaches that are used 

now are pretty much, at least throughout most of the country, is 

driving down the street in urban areas dispersing a fog or a spray 

or an ultra-low-volume insecticide that doesn’t reach into the backyard, and so the control strategies with pesticides is going to take 

much more applied when you target an area where active transmission could be occurring, go in and kill the mosquitoes in the 

yard, and that may be a homeowner-driven—— 

Chairman SMITH. Almost on an individual basis? 

Dr. PRESLEY. Yes, sir, become the individual homeowner until we 

have a technology like genetic modification like the sterile screw 

worm release 

Chairman SMITH. Thank you, Dr. Presley. 

Mr. Parry, my time has expired, so could you briefly respond? 

Mr. PARRY. Yes. I think we can actually target the mosquito now 

and drive it down to a level where it can’t transmit disease. I firmly believe that. I think it’s an integrated approach. I wouldn’t just 

rely on our technology but I think our technology provides the 

missing piece of the jigsaw, but really, we have now with our technology added in to what we have already a way of controlling this 

mosquito in urban environment and we should focus on the highrisk areas as a priority. 

Chairman SMITH. Okay. Thank you, Mr. Parry. 

The gentlewoman from Oregon, Ms. Bonamici, is recognized for 

her questions. 

Ms. BONAMICI. Thank you very much, Mr. Chairman, and thank 

you for convening this expert panel of witnesses. It’s been very enlightening. I have about 5 hours of questions but I only have 5 minutes, so I’m doing to start. 

Dr. Ernst, you said in your written testimony that we don’t know 

the complete distribution of the Aedes aegypti in the United States 

because surveillance for the mosquito is not consistent across jurisdictions and many don’t have the resources to carry out the surveillance needed, and Dr. Neafsey, you talked about a different of map-
66 

ping, the genomic mapping. So can you each address how close are 

we? Are we halfway there? Are we 25 percent there? And maybe 

just a mention of where we are in terms of resources as well, and 

then I want to have time for another question or two. Dr. Ernst? 

Ms. ERNST. I will try and answer briefly. So I would say that it’s 

very spotty where we have the surveillance data that is actually accurate and well collected. Some places do a great job and have a 

significant amount of resources. The majority of places do not. 

There are West Nile virus vector surveillance that is ongoing but 

the distribution, the way the ecological niche is for the Aedes 

aegypti mosquito, it’s different, so you have to have different traps 

and different location of those traps. I would say at least 80 to 90 

percent of the actual jurisdictions probably do not have active 

Aedes aegypti surveillance at this time. 

Ms. BONAMICI. Thank you. 

And Dr. Neafsey, on the mapping, how close are we, or how far 

are we, depending on how you look at it? 

Mr. NEAFSEY. I think we’re close. I think we’re making good 

progress towards having a better genetic map, but I think having 

a better genetic map for the mosquito is a proximal goal and the 

goal of applying that map most fruitfully to studies, for example, 

of insecticide resistance and identifying those markers that are 

most useful in the field for maintaining the efficacy of the control 

measures we do have. That will take further application of the genome map and testing of more samples. 

Ms. BONAMICI. Thank you. And many of you mentioned the urgency because of the summer weather that’s approaching. It’s almost June. Does anyone disagree that it’s becoming more urgent as 

the weather is getting warmer across the country and the world? 

Anybody disagree with that? 

So my next question is really for each of you. I was really surprised to learn that the Aedes aegypti mosquito can breed in a bottle cap of water. I don’t think that this is what people think about 

when they’re warned against keeping standing water around, and 

I know, Dr. Presley, you addressed this need for public health education, but what efforts are underway to educate people, and is 

there social science research about the most effective ways to communicate these kinds of messages? Are there—do we need more behavioral research on how to send the messages with urgency so 

that they’ll be understood and acted upon? Dr. Presley, do you 

want to start and then I’d like to hear from the others as well. 

Mr. PRESLEY. Yes, ma’am. There’s efforts underway in Texas, I 

know for sure, to put out using social media and online resources. 

There’s programs, there’s web pages that CDC has. There’s a lot 

of information out there. 

I did a Zika virus search last week and found 91 million results 

so—— 

Ms. BONAMICI. I don’t mean to interrupt, but maybe that gets to 

the heart of the question. Is somebody sees 91 million results, how 

do they know where to go to get something that’s effective? Are 

there—is the CDC known as the reliable source and the others 

are—you know, everything we read on the internet isn’t true so 

how do we get that message across in an urgent way? 
67 

Mr. PRESLEY. In Texas, in the local area I’m from, we’re sending 

it out in utility—little flier, a pamphlet in utility bills, and they’re 

going to do that—they started that in May and they’re going to follow through the summer with that. That’s really the only way that 

we found to make sure everybody at every level gets it. 

Ms. BONAMICI. Okay. I know a lot of people pay their bills online 

so I just don’t know if we’re doing what we need to do to reach people to get the message across. I think people are thinking well, if 

I have a pond I’m in trouble but otherwise I’m not, so how do we 

communicate that? 

Dr. Ernst, do you have thoughts on that? 

Ms. ERNST. Sure. So we’re doing a couple of things. One is try 

and engage people in social media but also to try and link that social media to whether or not it actually makes any kind of difference because there is a lot of advertising and there is a lot of 

information that’s out there but whether or not that actually translates into action on a person’s part is unknown. We are also developing a mobile application that people can subscribe to that has an 

educational component. I think that making sure that there is a cohesive on-the-ground network so in the area where I’m from, 

promotoras and community health workers can get that information out to areas where there are fewer resources and actually have 

one-on-one contact with most vulnerable communities. 

Ms. BONAMICI. Terrific. 

And Dr. Ernst, quickly, you mentioned that we don’t know how 

different environments and different environmental conditions may 

change the feeding habits. If somebody researching that, and what 

would that research tell us if we could answer those questions? 

How would we use that information? 

Ms. ERNST. Right. So in Phoenix where there’s a fairly good vector surveillance and control program, they actually noted that the 

Aedes aegypti mosquito were altering their biting behavior and 

were biting as early as 3 or 4 in the morning. Now, that’s anecdotal. They have not met published that information. But it seems 

like this is a very flexible mosquito, and it is able to modify its behavior in order to survive. 

Ms. BONAMICI. Fascinating. Thank you, Mr. Chairman. I yield 

back. 

Chairman SMITH. Thank you, Ms. Bonamici. 

And the gentleman from Oklahoma, Mr. Lucas, is recognized for 

his questions. 

Mr. LUCAS. Thank you, Mr. Chairman, and before I begin my 

questions, I would note that having known Dr. Presley since his 

graduate days at Oklahoma State, I have a little sense of co-ownership along with Congressman Neugebauer down there. 

That said, Doc, let’s turn to you for a couple of questions. Number one, in addressing the issues, and the panel’s laid out very well 

today the challenges we face, the ultimate goal of what we try to 

do, but there’s the short-term solution and there’s the long-term solution. Talk for a moment about—and you discussed this earlier— 

about the mosquito control perspective for a homeowner, whether 

it’s Lubbock or Stillwater or anywhere where this may be an issue. 

You’ve described how the traditional mass fogging systems going 

down the street won’t get everywhere. I know historically in the 
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past, we’ve done aerial spraying in certain cases. As I talk to my 

constituents, the off-the-shelf products you’re taking about, what 

kind of cost are we talking about for a homeowner to protect him 

or herself in their backyard? It’s not particularly expensive, correct? It’s the efforts involved? 

Dr. PRESLEY. No, sir, you can buy a home thermal fogger, which 

creates a cloud, a smoke cloud, essentially, in your backyard that 

will penetrate vegetation and you can buy the pesticides. You can 

buy the thermal fogger for a couple hundred dollars, a very good 

one, and then the pesticides may be $20 or $30 a month to keep 

mosquitoes down in your yard. 

The issue with these mosquitoes, albopictus and aegypti, is they 

stay pretty close to where they are hatched, about 200 yards, 300 

yards in an area. The foggers that drive up and down the streets 

are really for mosquitoes like culex tarsalis that vectors West Nile 

virus, and that with restrictions and how we’ve refined pesticide 

application, you’re relying on a small droplet of that insecticide impinging on the mosquito while in flight. That’s effective for crepuscular biters, or mosquitoes that bite at night or between, you know, 

sunset and dusk and dawn, because with Aedes aegypti and Aedes 

albopictus, they’re daytime biters primarily. So spraying with the 

fogger depends on before the thermal inversion occurs. When the 

sun comes up and the ground begins to heat, the currents are upwards, so these fogs, these clouds that you spray out of a ULV machine driving up and down the street will rise and dissipate. You’re 

trying to get with these daytime biters treating early in the morning with a fogger or a thermal fogger or a spray, just a wand spray 

treating under the eaves of houses, around doors and windows and 

vegetation. It’s a completely different strategy for vector control. It 

comes into private property issues, all of that. 

The homeowner is going to be responsible for dumping that bottle cap full of water or that toy dump truck in the backyard or anything that can collect water is a good breeding site for these mosquitoes. 

Mr. LUCAS. But our fellow citizens have the ability to protect 

themselves if they’ll take action based on the right information? 

Dr. PRESLEY. Yes, sir, and there are numerous over-the-counter, 

off-the-shelf products that can be bought at any big-box garden 

store or home improvement center. 

Mr. LUCAS. Now let’s go to the next step, Mr. Parry discussing 

an effort at a long-term solution. You mentioned the screw worm 

program so successful since the 1950s that most people don’t even 

know it exists. Would you expand on the problem we face in the 

Southwest, in the South, for that matter, what the solution was 

and how it has continued to be effective since then? 

Dr. PRESLEY. Oh, the sterile male release of screw worm flies. 

The primary screw worm, they’re a blowfly. They would oviposit or 

larviposit their maggots into a wound, and that particular screw fly 

would eat living flesh. Other blowflies will—— 

Mr. LUCAS. And any cattleman 65 years or older in Texas or 

Oklahoma will tell you it was a horrible thing. 

Dr. PRESLEY. And not only cattle, wildlife—whitetail deer, everything was affected. They came up with a sterile male screw fly release program where they irradiated the males and released them. 
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This particular species only bred once, the females, so it stopped 

the progression, and it essentially stopped—— 

Mr. LUCAS. For 50 years now. 

Dr. PRESLEY. There still are cases but it’s very controllable and 

managed on the Texas border now. 

Mr. LUCAS. So we have a track record of using these type of technologies to make a real difference systematic in the long haul? 

Dr. PRESLEY. Yes, sir. 

Mr. LUCAS. Thank you, Doctor. 

I yield back, Mr. Chairman. 

Chairman SMITH. Thank you, Mr. Lucas. 

And the gentleman from California, Mr. Bera, is recognized for 

questions. 

Mr. BERA. Thank you, Mr. Chairman. 

I’m going to put on my doctor cap here and public health perspective so with regards to travel advisory for those listening at 

home, just go to CDC’s Zika Travel Advisory, and you’ll get a lot 

of information and country-specific information. 

Going back as far as February, the advice has been, if you’re 

pregnant, do not travel to endemic areas. If you’re of childbearing 

age, the advice is not to travel to endemic areas, but if you are 

going to travel, to take precautions—birth control, et cetera. We’ve 

also been working with global health agencies to increase access to 

birth control in endemic areas until we get ahead of Zika virus and 

we fully understand what’s going on. 

If you have to travel to these areas, obviously take mosquito precautions, you know, repellants, et cetera avoid going out at dusk 

or the times the mosquito’s biting. 

In addition, you know, back in February, we had a hearing. We 

had Dr. Frieden and Dr. Fauci come over from the National Institutes of Allergies and Infectious Disease. Dr. Fauci at that time 

was quite optimistic that by the end of the year we’d have a vaccine for clinical trials. I will be honest, I was skeptical that we’d 

be able to develop something as quickly as that. 

You know, a few weeks ago I had a chance to go visit Dr. Fauci 

and his team at the National Institutes of Health. They will be 

ready for clinical trials, phase I trials, starting in September, and 

a very important aspect of our getting ahead of Zika is that vaccine 

development, and the science behind vaccine development. So, you 

know, September is still after mosquito season but we are moving 

fairly rapidly to get ahead of this and address it. 

The bigger component here, though, and each of the witnesses 

touched on this, is two years ago we were talking about Ebola, 

we’re talking about Zika this summer, and the world is a much 

smaller place right now, and vectors, infectious disease viruses 

move much more quickly. It’s not as though we haven’t known 

about Zika for, you know, years. We’ve known about this since the 

1940s. And it’s not that the virus has mutated. The virus has 

moved. It’s now in a densely populated area and, you know, we are 

starting to see this pop up, and what we have to do is as a body 

is, provide adequate resources to the CDC, to the NIH to do the 

research but to understand that we are going to be battling these 

infectious diseases much more frequently, and we’ve got to support 

the science. 
70 

Dr. Ernst, I’ll probably toss it over to you. With regards to both 

Zika—you know, certainly as we get a vaccine developed, disseminating that vaccine and making sure it’s effective, but then also 

just more broadly as an epidemiologist and someone who studies 

this, you know, what we ought to be doing right now to prevent the 

next infectious disease and how we ought to be thinking about 

some of this. 

Dr. ERNST. So you’re talking more broadly, any infectious disease? 

Mr. BERA. More broadly, yes. 

Dr. ERNST. More broadly? I mean, I think some of the things that 

we can do is really understand where a lot of these infections are 

originating from. A lot of these are diseases of poverty. They’re diseases where you have countries and places that have no infrastructure to be able to respond and control the epidemic in their own 

boundaries, and when you have something that is going on in another place and you have, as you said, a very globalized world, it 

doesn’t take a lot for those viruses or bacteria to come over here. 

So I think shoring up resources in other places to ensure that 

there’s fewer pandemics in those areas as well is a critical step, 

and then also investing in research and understanding where those 

threats might be more likely to come from is also very important. 

Mr. BERA. Wonderful. And again, I think for the public and for 

my colleagues in Congress, it is very important that we don’t just 

fight the disease here, that we actually go to where these infections 

and these viruses are endemic and originating, and there’s a reason 

why we fund global health, there’s a reason why we, you know, 

fund the CDC to go do research and go to these endemic areas, and 

as we look at these fundings and we look at our budgets, it’s really 

important for us, because if we don’t get ahead of this in those endemic places where the virus is, they will certainly pop up here, 

and we’ve seen it time and time again with SARS, with, you know, 

various infectious diseases, and again, in a smaller world, we will 

see this more frequently. 

You know, I’m running out of time. As Ms. Bonamici said, I could 

spend, you know, 5 hours asking questions, but we also have to 

then adequately fund the science as well so we can come up with 

those therapies to both control the vectors but then also to get 

ahead of this, and with that, Mr. Chairman, I’ll yield back. 

Chairman SMITH. Thank you, Mr. Bera. 

The gentleman from Texas, Mr. Neugebauer, is recognized. 

Mr. NEUGEBAUER. Thank you, Mr. Chairman. 

The United States has been very lucky that many of the potential global health pandemics have not become epidemic in the 

United States. However, it’s a little puzzling to me because you 

know, some of these things like Ebola and Zika have been around 

for a very long time, but what happens is, something kind of elevates their attention and then there’s a call then for the Federal 

Government to come and spend billions of dollars to be in a reactive mode. 

So I guess my first question to the panel this morning is, rather 

than being in a crisis mode on some of these things, what would 

be a better plan? Because I think what I always find is when we 

have crises, we don’t spend money as efficiently as we do when we 
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spend money when we’re planning for it, so kind of go down the 

panel, and in a perfect world, how can we get on the front of some 

of these rather than being in a reactive mode? 

Dr. ERNST. So I would concur with that. I absolutely agree that 

the reactive mode that we seem to be in, in terms of pandemic response and planning, is not as efficient. I think we have made 

some strides towards trying to be more ahead of the curve. We had 

a lot of preparedness funding that has come through the health departments to try and set up some of these response plans in place, 

et cetera, but I think we can do more. I think that we need more 

investment in trying to understand where and when and forecast 

some of these risks and be able to quell them before they can even 

actually start taking off, and that means having really better surveillance systems globally as well as even improving our surveillance systems here domestically. 

Dr. NEAFSEY. All right. So I second, you know, the importance 

of surveillance, and I can speak to work being done by one of my 

colleagues at the Broad Institute, Pardi Savetti, who was well positioned to apply DNA-based studies of the Ebola outbreak because 

she was establishing a research base in West Africa and starting 

to characterize fevers of unknown origin. There are many agents 

of infectious disease that result in symptoms and that are 

undiagnosable because we don’t know what the agent is, and there 

are many of these, particularly in tropical parts of the world, any 

one of which could in principle emerge to cause an epidemic. 

So I would advocate the importance of surveillance, the importance of catching new epidemics early, and the utility of DNAbased studies for getting an early characterization of perhaps the 

agent behind emerging outbreaks. 

Dr. PRESLEY. I agree completely with what’s been said. I’m much 

more applied in how I study vectors. It’s more not at the genetic 

level, it’s more transmission dynamics, how they behave, the ecology of the vectors. That is where I believe funding also needs to 

be focused. You’re right, this ‘‘everybody panic and throw money at 

it’’ doesn’t fix it, and I said it before. The Zika virus is just the latest of an emerging arthropod-borne threat, public health threat, in 

the United States. We had chikungunya last year, Valley fever before that, and we’ll have more because there are viruses out there 

that we know or suspect are vector-borne but they’re not in areas 

where we’re really concerned right now. West Nile virus had never 

occurred in the real world until 1999. Zika virus wasn’t in South 

America until last year, 2015. So viruses are moving around, and 

that’s part of—whether it’s climate change or global travel, speed 

of travel, they’re moving around. 

My basic belief is that we need to start at the applied level and 

train pest control operators. We saw a kneejerk response to Ebola 

where nurses and clinicians did not have the proper personal protective equipment, the most basic of supplies they need. I can draw 

a similar situation with vector control operators in mosquito control 

districts throughout the country right now. They don’t have those 

basic supplies they need knowledge-wise and resource-wise to attack this issue. 

Mr. PARRY. I think you have to look at the common element, and 

the common element is the mosquito. Control the mosquito, you 
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control all the diseases that it has spread, is spreading, and will 

spread. 

When I say control, I mean giving yourselves the capacity, the 

tools, and the procedures to exercise that control. In some areas, 

some may wish to eliminate the mosquito. In other areas one may 

wish to have the ability to drive it down below a disease transmission threshold, which is not actually the same as elimination. 

But having that capacity, having that ability to do that to me is 

the absolute starting point of it. 

Mr. NEUGEBAUER. Thank you, Mr. Chairman. 

Chairman SMITH. Thank you, Mr. Neugebauer. 

And the gentleman from California, Mr. Takano, is recognized for 

his questions. 

Mr. TAKANO. Thank you, Mr. Chairman. 

Mr. Parry, what you propose makes rational sense, statistically 

drive down the numbers of the mosquito control, the vector. Mr. 

Lucas mentioned the sterile—the sterilization of the male insect. 

Your process, though, is not sterilization, it’s about a genetically 

modified mosquito, and there’s some concerns of some environmental groups about the safety of this, and there’s some rumors 

that this genetically modified mosquito actually transmits the 

virus. Can you just quickly clear that up? Because I have a lot of 

other questions I want to ask. 

Mr. PARRY. Yes. I mean, our mosquito is modified in two ways. 

It can’t reproduce, and it carries a color. It’s no more or less capable of doing anything else than normal mosquitoes. There is no difference. In terms of the environment, actually I think our mosquito 

is far safer and softer on the environment than any other intervention. It’s not a toxin. You’re just taking out one insect. You’re not 

affecting the rest of all the food chains. 

I think it is a shame in many ways that there has been a concern 

over the words ‘‘genetic modification’’ in society. That’s been there 

for several years now. And really, we need to be able to distinguish 

products by what they are, what they do, what the risk profile is, 

rather than assign a tag or a label. 

But ultimately, with our product, it’s like any other. It’s—we provide the evidence to the actual arbiter. At the end of the day you 

go through the regulatory process. The evidence is weighed up and 

you have an outcome that’s based on science and facts. 

Mr. TAKANO. So with respect to Zika in this particular case, it 

seems controlling the vector is really important to keep what transmits the virus from doing that, and so reducing the numbers of 

mosquitoes is really important but also coming up with better technologies on repellants. 

In my own district, the University of California Riverside, which 

is known as a great center of entomological research—I see a lot 

of nodding heads. Dr. Neafsey, are you familiar with Olfactor Laboratories, which is an attempt to monetize the research that was 

done in a laboratory by Dr. Anandasankar Ray, who is basically focused on trying to deal with the carbon dioxide receptors of the 

mosquito. You mentioned that some mosquitoes are able to distinguish between human and animals, but what’s common is that 

they’re kind of attracted to this carbon dioxide marker. Is that 

right? 
73 

Mr. NEAFSEY. So yes, that’s right. I think there are a number of 

cues that lead mosquitoes to their host for a blood meal. Carbon 

dioxide is one such cue. What is amazing is that many mosquitoes, 

particularly those ones that are most culpable in transmitting 

human diseases, are very human specific so they’re responding to 

carbon dioxide but they’re also responding to other unique signatures of human odor. I think developing repellants, developing 

strategies that capitalize on our rapidly growing knowledge about 

the molecular biology and the neurobiological basis of how mosquitoes perceive these cues is a fantastic research direction and I 

think you’ve cited a good example of how it’s actually translating 

into intervention measures of repellants. 

Mr. TAKANO. This is a great example of how basic scientific research in a laboratory has these very practical effects and is being 

furthered by private-sector-funded efforts to monetize that research. I understand that they’ve developed a patch, something 

called a Kite patch, which can just be worn on clothing which interferes with the mosquito’s ability to perceive these—what do you 

call them?—these markers or—— 

Mr. NEAFSEY. Cues. 

Mr. TAKANO. Cues. The cues. The cues, the chemical cues. What’s 

exciting about that is that it seems less—has less impact on the environment with the use of these pesticides. So this is a very promising line of research is what I perceive. 

Mr. NEAFSEY. Absolutely. I think we’re positioned now rather 

than to use sort of a random strategy for finding chemical 

repellants or other interventions, we can really use our knowledge 

to pursue these strategies with a rational basis, with a thorough 

understanding of the mosquito biology, and these have great potential. 

Mr. TAKANO. Well, I hope that we can work together on both 

sides of the aisle to promote a number of strategies to deal with 

this vector. 

Mr. Parry, you certainly propose, I think, a very rational strategy, and Dr. Neafsey, you’ve confirmed my excitement about what’s 

going on in my own district on this research, and to the extent that 

we can buttress what’s going out there—and Dr. Ernst, what you 

say about global poverty and making sure that we take care—that 

there can be no weak link. We can’t allow any country to have a 

dysfunctional public health system. It comes back on us. 

I yield back, Mr. Chairman. 

Chairman SMITH. Thank you, Mr. Takano. 

And the gentleman from Louisiana, Mr. Abraham, is recognized. 

Mr. ABRAHAM. I thank you, Mr. Chairman. I think we certainly 

have a great panel here, and with your minds and minds out there 

working on this, we can probably cure this issue. 

Going back to Congressman Neugebauer’s argument of being reactive instead of proactive, the Federal Government is unfortunately often reactive, in my opinion, and it’s like sending the Hindenburg to rescue the Titanic. We need to be better than that. We 

should be better than that at this stage of the game. 

Mr. Parry, the CDC, I think in February, elevated Zika to a level 

one activation, and you can help me, but I think I recall that the 

only other time was Ebola was active one, H1N1, and being in Lou-
74 

isiana, I remember post Katrina was a level one activation. So my 

question to you is, you’ve got evidently something that works here. 

You said you could get a 90 percent reduction in mosquito population in six months, which is, to me, a phenomenal feat. If CDC 

thinks this is so important, and I can assure you, it’s very important—I’ve treated microencephaly and microencephalitic children, 

and it’s a horrible, horrible thing for a child to undergo that, and 

their parents also—what is the FDA telling your company as to 

why it won’t give you an emergency declaration? I mean, you’ve 

been after this since 2011 according to your testimony. We know 

this is bad. We don’t want any child to be born with microcephaly 

or microencephaly. What’s the answer FDA is giving you to why 

can’t we do this now? 

Mr. PARRY. The answer we have received is, it’s complicated. 

Mr. ABRAHAM. Well, come on. We’ve got wonderful scientists here 

including yourself that tells us we need to act now. We should have 

acted a year ago. 

Mr. PARRY. I absolutely agree. We’re being treated as an investigational animal drug as the sort of product class, if you like, because the genetic modification is a DNA insertion, which means 

that from the FDA perspective, they would have to approve an animal drug in order to provide a public health benefit. 

Mr. ABRAHAM. But you’ve got objective data that says this works 

now. 

Mr. PARRY. Exactly, and I think that’s exactly the way we should 

go. We need to go down the emergency—— 

Mr. ABRAHAM. We’ve got to kill these mosquitoes. I mean, I understand, look, I think it’s critically important what we’ve talked 

about, better repellants like Mr. Takano said, certainly spraying individually, but until we kill the mosquito, we can kill all we want 

to in our house but they’re going to come back in. Mosquitoes are 

going to come from the islands, they’re going to come up from the 

South. We’ve got to quit putting Band-Aids on this. We’ve got to 

go to the root cause. The root cause, like you alluded to, is a mosquito, and somebody asked about pandemics worldwide, and again, 

yellow fever, dengue, malaria, all these are vector-borne, and we’ve 

got to kill the source. 

So, you know, I’m very frustrated as I am with many government 

agencies, unfortunately, but with the FDA in this instance, it’s out 

there, we know it’s here and we need to do something, but they’re 

putting up blockages to your company and other companies like 

yours. 

Mr. PARRY. I think we should encourage them to find the processes to make this happen. 

Mr. ABRAHAM. Is the cost of your technology any more costly 

than spraying, traditional spraying? 

Mr. PARRY. I think in terms of cost efficacy, ours will be streets 

better, to be honest. 

Mr. ABRAHAM. Okay. And to the panel, I’ve just a couple of 

science questions. Is this an intracellular or an extracellular virus? 

Does it live in the RBC, the WBC or is it in the plasma? Where 

does it live in the human? 

Mr. NEAFSEY. I think it replicates in cells, and I think work is 

underway on elaborating exactly which cell types are most favored 
75 

by the virus. I think there was this convincing work a few weeks 

ago with brain tissue organoids to establish its affinity for developing around the cells, but I would say that the preferences for the 

types of cells infected by the Zika virus are still being elaborated 

upon. 

Mr. ABRAHAM. And Dr. Ernst, you said that certainly the mosquito vectors like the Aedes aegypti and the albopictus transmit 

not only Zika but other diseases such as dengue, yellow fever. 

When a mosquito that’s infected with Zika and those other diseases 

bites somebody, are both viruses or more than one transmitted at 

the same time, or does Zika take precedent? Who wins that battle? 

Dr. ERNST. That’s a good question. I don’t think we know that 

yet. There’s certainly some evidence that mosquitoes can be co-infected with dengue and chikungunya but I’m not sure what the status of the research is right now on the interactions between dengue 

virus, for example, and Zika virus. I don’t think we know that yet. 

Mr. ABRAHAM. And one quick question. My time is out. After 

somebody’s infected with Zika, is there antibodies built up? Can we 

test for antibodies in that person? 

Dr. ERNST. Yes, we can test for antibodies for Zika but it’s very 

difficult to disentangle if the person has had a previous dengue infection. Then when you try and test for antibodies, it becomes 

equivocal. The results become very difficult to interpret. 

Mr. ABRAHAM. Well, Mr. Chairman, I have a thousand other 

questions also but my time is up so thank you very much for allowing me to go over. 

Chairman SMITH. Thank you, Mr. Abraham, and the gentleman 

from Colorado, Mr. Perlmutter, is recognized. 

Mr. PERLMUTTER. Thank you, Mr. Chair. This is a very fascinating hearing, and obviously—my question is going to be a little 

more parochial. I’m from Colorado. Looking at those maps that you 

presented to us, we’re not really in the region that can anticipate 

Zika, the Zika mosquito, the egyptus or whatever it is. 

So I’d like to start with you, Professor Presley, because you mentioned West Nile, which is something that we’ll get a couple cases 

of West Nile in Colorado pretty much every year. Can you just for 

a layman like myself kind of explain the difference between the 

mosquito that delivers West Nile versus the mosquito that delivers 

the Zika virus? And then, you know, how are we managing West 

Nile mosquito versus the Zika mosquito? 

Mr. PRESLEY. The West Nile vector is—and I’m not sure what 

part of Colorado you’re talking about. 

Mr. PERLMUTTER. Denver area. 

Mr. PRESLEY. On the high plains? 

Mr. PERLMUTTER. Yeah. 

Mr. PRESLEY. It’s culex tarsalis, and that mosquito breeds in 

pools and ponds, standing water, so we can survey for them. Their 

activity is primarily crepuscular, right after dark and right before 

sunrise. Contrast that to Aedes aegypti and Aedes albopictus that 

are vectors of Zika virus, and they like to—they’re container breeders. It’s fresher water typically in small containers in the axles 

of—— 
76 

Mr. PERLMUTTER. When you say small containers, tell me what 

you mean by small containers. I’m trying to think. You ship them 

in boxes or what? 

Mr. PRESLEY. A tuna can is more than—an empty tuna can is 

more than enough water. They will breed in the leaf axles of 

vermillion plants like in the house. You know, a comment was 

made about just outside. No, these mosquitoes will live in the 

house. They like to be in the house, hotel rooms. So just treating 

the outside doesn’t control them. So these differences in where they 

breed and where they like to bite and rest are significantly different. You know, they’re daytime biters, and it’s really right after 

sunrise—typically right after sunrise. Then they rest during the 

heat of the day and they bite right before sunset when it cools back 

down. That’s not a rule but that’s generally. 

Mr. PERLMUTTER. So in controlling them—and Mr. Parry, maybe 

I’ll direct these questions to you for a second and then to the whole 

panel. So—and I don’t know the Latin term but I’ll call them the 

West Mile mosquito and the Zika mosquito. In your use of more or 

less a sterile male to defeat the virulent female or, you know, cause 

the death of the species, do you guys do any work on the West Nile 

mosquito? 

Mr. PARRY. Not yet. So we’ve obviously developed aegypti. We 

can do anopheles, which is the malaria mosquito. We’ve actually 

done proof-of-concept work there. We’re actually developing Aedes 

albopictus, which was also mentioned earlier, so that is actually 

coming through the R&D system and is a candidate product. 

With the culex mosquitoes, the West Nile ones, we’ve looked at 

those. We think they’re very tractable actually. We can do them. 

The research team is very confident but we haven’t proven that 

yet. 

Mr. PERLMUTTER. In Colorado, I think Professor Presley, we have 

up at Colorado State University, you know, studying the Zika virus 

and mosquitoes. Do we—I guess my question is, the symptoms of 

West Nile can make you—you get really sick. More negligible obvious symptoms with the Zika virus but the potential damage to the 

fetus or to the baby is tremendous. So I guess my question is similar to Mr. Abraham’s, we ought to be allowing every possible defense whether it’s using an insecticide or sterility, and I would— 

on the insecticide part of this, do we have any breakthroughs? It 

sounds like Mr. Parry has a good approach on the sterility. Do we 

have any breakthroughs on the insecticide piece of this against the 

Zika virus and the Zika mosquito? 

Mr. PRESLEY. We do, Congressman. There are some very effective 

pesticides, but the whole insecticide resistance issue in these species is critical, and we don’t know where resistant populations are. 

In the State of Texas, we’re going to find out in Texas, but there 

needs to be, I think, a national effort where these mosquitoes are 

documented to occur to find out what insecticide resistance does 

exist in the population so we can knock them down immediately 

and then rely on long-term strategies to keep them numbers down. 

And I would just add in that West Nile virus when it first occurred and during the first few years of its occurrence in the 

United States was considered to be West Nile fever predominantly, 

which was relatively mild symptoms. Now it’s predominantly West 
77 

Nile neuroinvasive disease. The virus has changed over time. We 

don’t know what Zika is going to do because it’s only been in the 

new world in South America for a year. There’s a lot of challenges 

there. 

Mr. PERLMUTTER. Thank you, Mr. Chairman. 

Mr. PARRY. I had a point. 

Mr. PERLMUTTER. Oh, go ahead. 

Mr. PARRY. Sorry. I know that’s not done, but I’d just like to add 

a point. 

The issue of insecticide resistance is a very real one, but when 

you get to the Aedes aegypti, which is the Zika transmitter, the 

biggest issue is private property actually because this mosquito 

lives in and around the home. For chemicals to be effective, you’ve 

got to have a public health authority coming into your house, your 

child’s bedroom, your kitchen pretty much every week, and that 

doesn’t work with modern society. 

Mr. PERLMUTTER. Thank you. 

Chairman SMITH. Thank you, Mr. Perlmutter. 

And the gentleman from Alabama, Mr. Palmer, is recognized for 

his questions. 

Mr. PALMER. Thank you, Mr. Chairman. 

Dr. Presley, given that the symptoms of Zika virus in adults are 

associated with a host of other ailments, how likely is it that a general practitioner may not have seen a case of Zika and therefore 

be able to accurately diagnose it? 

Dr. PRESLEY. Excellent question, Congressman. You know, we 

say the facts that are out there or the information out there is that 

only 20 percent are symptomatic with infections. Flu-like illness of 

influenza-like illness is so common in talking to my physician 

friends, how many infections are we saying, it looks like a virus, 

go home, rest, plenty of fluids, you’ll be fine, and it never gets tested. So I think that these estimates of the number of infections in 

an area are way underestimated but there’s no way that you can 

nail that down. It’s like West Nile or flu, influenza. 

Mr. PALMER. Do physicians have the necessary diagnostic tools? 

I mean, is there something out there that they could use to make 

sure they make a more accurate diagnosis? 

Dr. PRESLEY. The current restrictions on human diagnostics, and 

my lab is one lab that does that but there’s certain criteria both 

clinical and epidemiological criteria like have you traveled or been 

exposed to somebody that did travel in a Zika infectious area, and 

then the local public health authority has to authorize that test 

being performed. Those tests, diagnostic assays, can only be done 

at CDC LRN laboratories, and we’ve done a couple over the past 

few weeks, but it’s a long administrative trail. 

Mr. PALMER. It sounds like we need a kit, some—— 

Dr. PRESLEY. Yes, sir. 

Mr. PALMER. —something like that. Let me move on. Thank you 

for your answer. 

Dr. Ernst, in your testimony you described the Zika map that 

you helped developed to try to predict where Zika might spread in 

the United States. Have we stopped short of calling it a forecast 

because there’s still too many unknowns? How would you improve 

your model to provide a better forecast for Zika or other vector- 
78 

borne diseases and what resources would a team need to provide 

a better forecast? 

Ds. ERNST. So I think there are several key components that 

would be helpful to improve for model results. One is being able to 

have better validation. So we were lucky enough to find a couple 

of data sets to validate our model outputs, but as has been mentioned multiple times, having actual robust surveillance programs 

that allow us to test our results against the actual data is one step. 

Another step is having more information on the specifics of the 

host vector interactions, so critical are things like the extrinsic incubation period. We don’t really know what that is. We don’t know 

its temperature dependency. We do have some work that’s going on 

in one of my collaborator’s labs to identify that. And some other 

issues are really understanding the social side. So there are absolutely different factors like poverty, vector-human interaction that 

need to be incorporated into models in order to really predict that 

risk. 

Mr. PALMER. I want to move to another question. Mr. Parry, we 

banned DDT, and by some estimates, there are 50 million people 

who have died from mosquito-borne diseases, and just in regard to 

the new science that we’re trying to posit, what are the odds and 

potential consequences of the offspring of Oxitec genetically modified mosquitoes developing resistance or tolerance to the self-limiting gene they acquire? 

Mr. PARRY. We haven’t seen it. We’ve gone through over 200 generations now of our mosquito. We’ve seen no resistance developing 

at all. There are certain biological issues and also the way in which 

the technology is being done, so we’re not expecting to see it, but 

any scientist will say you’ll never say never. 

I think the issue is, what does our product actually do. It stops 

the mosquito from breeding. So what happens if it doesn’t work? 

Well, then the mosquito can breed, so it becomes a normal mosquito. 

Mr. PALMER. Well—— 

Mr. PARRY. So effectively we would stop releasing. 

Mr. PALMER. Looking at the situation from another angle, is 

there any chance that the Oxitec technology might eradicate the 

Aedes aegypti breed of mosquitoes? 

Mr. PARRY. Mosquitoes only fly about 200 yards in their lifetime, 

so actually the effect when you’re releasing our mosquito is in the 

area in which you’re releasing it. So you actually have to be very 

deliberate about where you go, how you control it, and against all 

of the issues you’ve raised, we have the marker. We have something that no one’s ever had, which is the ability to track and trace 

exactly what we’re doing so we pick up that metric all the time. 

Mr. PALMER. Well, I’m out of time. My last question is, one of our 

colleagues on the Committee talked about CO2 as a marker apparently in the context of climate issues. Is it any of your recommendations that we breathe less? 

I yield back. 

Chairman SMITH. Thank you, Mr. Palmer. 

The gentleman from New York, Mr. Tonko, is recognized. 

Mr. TONKO. Thank you, Mr. Chair, and welcome to all of our experts for very valuable information. 
79 

Dr. Ernst, in your testimony, you discussed community-based 

surveillance activities including USDA’s efforts to encourage participation by community members. There’s no doubt that we need 

to invest more resources into surveillance. In particular, I’m encouraged by efforts to use crowdsourcing and citizen science methods within the Federal Government to advance and accelerated scientific research and literacy. One example of this is USDA’s 

Invasive Mosquito Project, the IMP, which was launched recently 

as an initiative that pairs high school teachers and students with 

mosquito control and public health professionals. This partnered 

citizen science classroom project helps high school teachers meet 

the next-generation science standards and students learn about 

mosquitoes, public health, and safety. The project is aimed at monitoring invasive container inhabiting mosquito species across the 

United States. According to the project’s description, by doing this 

monitoring, we can determine where the invasive mosquito species 

as well as the native species are distributed across the United 

States and define at-risk human and animal populations based on 

this distribution. 

With all of that said, can you speak more about why projects like 

these can help with surveillance efforts as well as providing enhanced public education? 

Ms. ERNST. Sure. So I think that these kinds of projects are great 

for a number of reasons. We’ve carried off some of these in Arizona 

specifically as well. We developed something called the Great Arizona Mosquito Hunt, and that engaged high school students to set 

out the ova position cups, which is a fairly sensitive measure of detecting whether or not there are mosquitoes present or not, and it 

allowed them to go through an educational module to teach them 

about the mosquitoes. 

So I think these kinds of efforts not only can be broadly disseminated to a large group of people but it’s also targeting young children as well as teachers who can pass that information on to their 

parents and really help be vigilant about mosquito control within 

their own household. 

I think that there is some things that need to be ensured for 

these kinds of projects including standardization of the methods to 

ensure that when you do get a negative that it is because there is 

not a mosquito around. That’s one of the things that’s difficult to 

determine. We found a lot of negatives in the high schools where 

we placed traps in part because, as the gentlemen have said previously, it doesn’t fly very far and school grounds are generally 

kept pretty clean. So really understanding some strategies to 

standardize this process to yield the best success are also important. 

Mr. TONKO. Thank you. And to you also Dr. Ernst, in reading 

testimony for today, I was struck by how we do not have a good 

idea of where the mosquito that transmits the Zika virus lives. You 

have done research into modeling the geographic areas with higher 

potential risk for local Zika transmission. Can you please describe 

that study and how forecasting studies like yours could help decide 

where to invest our resources? 

Ms. ERNST. Sure. So this was sort of a first cut, I think is what 

we basically have been stating, in trying to understand where the 
80 

Aedes aegypti might be present in the United States as well as the 

seasonality of the vector, and it really is based upon what we know 

about the dynamics of the mosquito and how it relates to climate 

and weather. So most of the stages of the mosquito are sensitive 

to temperature as well as precipitation for the aquatic stages of the 

mosquito so we can leverage information on sort of average—what 

we did was, we took average ten years. worth of data to look at if 

you had the weather that’s sort of typical in these cities, when 

would you see Aedes aegypti abundance, and then we compared 

that to an area where we know there’s fairly good conditions. We 

compared it to the numbers that we had in Miami. And so the map 

that we actually depict is relative abundance, so it’s relative to sort 

of the high season in one of the most climatically suitable places, 

and we look to see how different that might be for the other 49 cities that were mapped and modeled. 

I’m sorry. I can’t remember the second part of your question. 

Mr. TONKO. Well, it was just how we could best use that information to decide where to invest resources. 

Ms. ERNST. Right. So, you know, some of the other layers that 

we have incorporated are related to travel introduction. So obviously without any local transmission at this point, it would have 

to come from somebody who had traveled outside the country and 

brought back the virus. And then as well needing to understand 

poverty and other factors that might facilitate more vector-human 

interaction. 

Some of the things that you can use the data that we presented 

for are understanding when theoretically you’re going to have a 

higher peak of mosquito activity within your jurisdiction if you’re 

on the map as well as trying to look to see, has your jurisdiction 

actually had dengue or chikungunya in the past. That’s another 

piece that we mapped into that study. 

Mr. TONKO. Thank you very much. I sense, Mr. Chair, that 

there’s a degree of urgency to invest here and invest wisely and 

deeply into this program. 

If I might take the liberty, today is an opportunity for foster 

youth to shadow individual legislators, and if I might introduce 

right behind Congresswoman Clark, we have Steven Fallon, who is 

my shadow today as a foster youth, if you’ll recognize Steven, 

please. 

Chairman SMITH. Thank you, Mr. Tonko, and the gentleman 

from Michigan, Mr. Moolenaar, is recognized for his questions. 

Mr. MOOLENAAR. Thank you, Mr. Chairman. 

Dr. Ernst, in your testimony you identified some of the knowledge gap areas about the interaction between the Zika virus and 

the mosquito that spreads it. 

I was also curious, Dr. Neafsey, the work you’re doing to sequence and map the genome, is that going to help fill in some of 

the gaps in knowledge, and kind of where are we in that process, 

timelines, those kinds of things? 

Dr. NEAFSEY. Sure. So I think I can attest to the value that genome sequences can have as a resource for informing precisely the 

kinds of parameters that make the types of models Dr. Ernst described accurate. In the malaria field, we’ve been using this kind 

of data to inform models of malaria transmission and malaria dis-
81 

tribution. One example of the way these data can be used is a 

study that was published last year by investigators at Notre Dame, 

who did genetic profiling of Aedes mosquitoes from the Capitol Hill 

neighborhood, and used the genetic signature of these mosquito 

samples over the course of several years to determine that this was 

a year-round population, likely a year-round population, taking refuge in sewers and below ground during the cold winter months 

rather than a new population that was being refounded by genetically different sources with every successive warm season. So this 

is a small example of some of the resolution that DNA-based data 

can lend to some of the parameters that are useful for understanding the existing and maybe the prospective distribution of 

mosquitoes. 

Mr. MOOLENAAR. I was reading a little bit about you’re kind of 

communicating via Twitter and periodically getting together, like 

kind of work projects in place, and how do you monitor who’s doing 

what and—— 

Dr. NEAFSEY. So Twitter is a fantastic scientific resource. I don’t 

know if it’s recognized outside of the scientific community but news 

travels so quickly. It is unparalleled for organizing people who are 

like-minded and who want to get behind a common cause. 

So Twitter, I think, and a lament about the quality of the existing Aedes mosquito genome map was the genesis of this working 

group I alluded to. Since then we’ve had phone conversations, 

emails, but as yet no in-person meeting. As I mentioned, this is 

kind of a volunteer group, and we’ve been working catch as catch 

can to this point. 

Mr. MOOLENAAR. I know you don’t want to commit to a timetable 

of when, you know, the completion of the assembly of the DNA map 

but can you give us a rough ballpark? 

Dr. NEAFSEY. I can say that we have efforts, parallel efforts, underway using several different new technologies that we hope will 

yield a better genome map on the order of a month or two. These 

are unproven but we’re very optimistic given their performance 

with sequencing human genomes and assembling maps for human 

DNA. So I think we’re optimistic that we won’t have a perfect genome map by this fall but we will have a map that is significantly 

improved beyond the existing one. 

Mr. MOOLENAAR. Thank you very much. I yield back, Mr. Chairman. 

Chairman SMITH. Thank you, Mr. Moolenaar. 

And the gentlewoman from Massachusetts, Ms. Clark, is recognized. 

Ms. CLARK. Thank you, Mr. Chairman, and thanks to all the 

panelists, especially Dr. Ernst, thank you for making your decision 

to skip that milestone. We appreciate the information that you all 

are bringing to us today. 

I wanted to start with something very specific and sort of move 

to the more general. The impact of this virus on a fetus is one of 

the most frightening aspects of a rapidly changing landscape but 

do we know now exactly how the virus causes birth defects like 

microcephaly and do we have an understanding of how exposure at 

different times of pregnancy can impact the fetus, or is this a gap 

in our research? 
82 

Mr. NEAFSEY. I don’t think we have a virologist on the panel but 

I’m going to step slightly outside my comfort zone just to provide 

a basic answer and say that, you know, the general principles that 

determine what cells and what hosts a virus can infect often come 

down to the particular proteins or other attributes that are on the 

surface of those cells. The virus usually needs to recognize a doorway and be able to interact with it in a way that permits entry. 

So some of the work that’s been done to date has taken advantage of some of these fantastic new resources in a laboratory such 

as these brain organoids, very simple, very small, three-dimensional tissue replicas of what a developing brain might look like 

and the realization that that has led to is that there are, you know, 

particular cells at stages of brain development that are indeed susceptible to Zika infection. I think there’s much work to be done to 

understand, as I mentioned previously, the spectrum of cell types 

that could be susceptible to Zika infection and the precise proteins 

and sort of molecular interplay that’s responsible for Zika’s ability 

to infect the cell types and the range of organisms that it does infect on the host side as well as, let me say, the mosquito side. Its 

ability to proliferate within mosquitoes and be injected into people 

that are bitten subsequently is another aspect of the molecular biology that I think we need to determine. 

Ms. CLARK. Dr. Presley? 

Mr. PRESLEY. If I could add, ma’am, there is so little known right 

now about how the Zika virus interacts in the body because we all 

looked at each other and shook our heads. 

Ms. CLARK. Right. 

Mr. PRESLEY. You know, something to consider, and it’s another 

area that we’re going to have to find out about is, you know, you 

may not be able to find it in a person’s blood after they’ve recovered. A week or so after being viremic, you might not be able to 

find it in the blood, but they’re finding it in semen 60 days after 

recovery or no more symptoms. The virus is going somewhere, hiding somewhere. There’s a lot of viruses that do that, whether it’s 

deep organ or whatever. I think there’s a lot to learn. I think we 

can agree on that. 

Ms. CLARK. And I think that brings me to a more general point 

that may be even harder to answer, especially in under 2 minutes, 

but as we have a discussion about how we react as Congress and 

in funding and when we get into pandemic mode, do we not make 

the most efficient choices, but here we are with this very frightening virus that is only one potential just mosquito-borne virus 

that has changed very quickly, spread very quickly around the 

globe and now in the United States, and we have very little understanding, and as I listened to your answers with the need for 

diagnostics, looking at resistance, mosquito control, dealing with 

issues of social behavior, private property, how we balance those, 

also looking at vaccines, understanding the genome, on and on, 

how do we approach these? And I have some concerns about the 

way we have funded our response by taking it from funding from 

other important diseases, and what is the better way? 

One of the most terrifying conversations I ever had was at the 

Broad looking at antibiotic resistance and infections, so how can we 
83 

do a better job of funding basic science that allows you to do the 

applied science that can bring us some answers in 22 seconds? 

Mr. NEAFSEY. I can speak briefly. I think what’s important is to 

set up an infrastructure for collecting and pooling information. I 

think there are a lot of investigators collecting diverse forms of information, and I think there are opportunities to really rapidly advance our state of knowledge about Zika and other emerging 

epidemics on the horizon by organizing that information, creating 

communication channels, not just exclusively via Twitter but other 

media, and making sure that we are performing surveillance, that 

we’re collecting the kind of information we need to in the short 

term limit the advance of these diseases and in the longer term understand them so that we can develop longer-term control measures. 

Ms. CLARK. Thank you. I see I’m out of time. I yield back. 

Chairman SMITH. Thank you, Ms. Clark. 

The gentleman from California, Mr. Swalwell, is recognized. 

Mr. SWALWELL. Thank you, Chair. Thank you to our panelists. 

People at home are terrified about Zika, and for good reason. I’ve 

gone across the country with a group called Future Forum. It’s 18 

of the youngest members of our Democratic Caucus, and we’ve engaged with thousands of Millennials, young people who already are 

having financial difficulties, starting a family, and now I think 

Zika, from what we’ve heard, is an additional just health difficulty 

that has been posed as far as when it comes to travel and planning, 

for starting a family. 

So my first question in light of that, does anyone on the panel disagree with the science behind the President’s request for $1.9 

billion for addressing this crisis? 

Seeing that no one has answered, is anyone familiar with Ronald 

Klain’s opinion piece in the Washington Post this weekend, ‘‘Zika 

is coming but we’re far from ready’’? Has everyone read that piece? 

In that thoughtful piece, Mr. Klain points out that the funding approved in the House for the Ebola—taking money from the Ebola 

crisis to address the Zika crisis is like sending all the fire trucks 

from one city to help fight a blaze in another. It’s short-sighted and 

dangerous. He also suggests that we should look at—to plan for future crisis like this having a public health emergency management 

agency. Any thoughts from any of the panelists as far as having a 

separate agency similar to FEMA but focused on public health 

emergencies? Yes, Dr. Presley? 

Mr. PRESLEY. I think one of the situations—and I don’t know 

about California but Texas is a home-rule state, so everything— 

every emergency is handled at the local level until other support 

is needed, and this is mainly to your last comment. Making another federal agency to funnel down money and hope that a little 

bit finally gets to the bottom on the ground, I do not think works. 

I think that’s part of the problem now is we don’t have the on-the— 

the boots-on-the-ground support that’s needed. 

Mr. SWALWELL. Yes, Dr. Ernst? 

Ms. ERNST. I’d just like to echo that. I also think that, you know, 

maybe something within one of the existing agencies, for example, 

the Centers for Disease Control, which has been leading a lot of the 

response in Puerto Rico, for example, but I also think trying to fig-
84 

ure out a way where we can leverage other resources besides federal or state employees to respond would also be something that’s 

useful. You know, every time that there’s a crisis, there’s a lot of 

volunteers, physicians and nurses and public health professionals 

who want to help, and we don’t really have a good infrastructure 

in which they can be trained and deployed to help in these emergency situations. And so I think having some sort of infrastructure 

where people like myself and maybe some of the other panelists 

could use their expertise to help in the response would be really 

beneficial. 

Mr. SWALWELL. Great. Thank you. And my perspective is that 

people at home and across the country, they don’t care whether it’s 

a Republican solution or a Democratic solution that solves this; 

they just want to see government act in a crisis and get it solved. 

So thank you, Chairman. I yield back. 

Chairman SMITH. Thank you, Mr. Swalwell. 

And the gentlewoman from Maryland, Ms. Edwards, is recognized for her questions. 

Ms. EDWARDS. Thank you, Mr. Chairman, and thank you very 

much to the witnesses today. I really appreciate your testimony. 

Just a few weeks ago—I’m the Co-Chair of our Democratic Steering and Policy Committee—we held a hearing with Dr. Fauci, the 

Centers for Disease Control, the American Public Health Services, 

a mayor or so, about Zika, and one of the things that surprised me 

because I didn’t know very much in looking at the maps, both the 

maps that we have here today but also other maps showing where 

the spheres of outbreaks are going to occur, it’s pretty daunting, 

and especially if you look through the Gulf states, the South, and 

the Mid-Atlantic region. 

And so my question actually has to do with the spread because 

although I understand there’s a particular type of mosquito, I was 

surprised to know, and maybe I’m wrong about this, that whether 

the Aedes aegypti—is that how you pronounce it?—mosquito, once 

it transmits to a human host, then can another mosquito, the traditionally found Asian tiger mosquito in the East, then transmit infected blood to another human being, or is that something that we 

know? Because to me, that suggests that we have just, you know, 

much more potentially out-of-control circumstance. And I recognize 

there are a lot of things that we don’t know, and this is tied to how 

we need to think about things like insecticide resistance and 

whether we then have the capacity for the boots on the ground to 

have the resources that they need to be able to respond should 

there—which I presume there will be a much wider spread or outbreak. If anybody has any thoughts on that, I’d appreciate it. 

Mr. PRESLEY. On the transmission, if Aedes aegypti or Aedes 

albopictus—you mentioned the Asian tiger mosquito—it’s not the 

blood, the infected blood, that they’re moving. Dr. Ernst has talked 

about extrinsic incubation, and that’s once the mosquito picks up 

that virus, that virus has to move through the mosquito’s body into 

the salivary glands, where it can replicate, the traditional model. 

And so there’s a period of time, up to a week, more information’s 

needed. So it’s not like the mosquito can feed on the person and 

immediately go bite another person and be infected. 
85 

Ms. EDWARDS. But then—I mean, the question gets—that I have 

is, does it really matter what type of mosquito then? 

Mr. PARRY. Yes, it does. In this respect, Aedes aegypti, the way 

to think about it is, Aedes aegypti is public enemy number one responsible for far and away the greatest level of disease transmission, whether it’s dengue or chikungunya and now actually 

Zika. So Aedes albopictus is a species which actually in its behavior 

it’s quite aggressive. It’s a nasty biter, worse actually then aegypti. 

You notice it worse. The bite is worse. But actually it’s a very inefficient disease vector. So in an ideal world, one would tackle both, 

but if you’re looking at disease transmission and how to make an 

impact, tackle Aedes aegypti. 

Ms. EDWARDS. Got it. 

And then if you could talk again about the incubation period, because I think part of the testimony that we’ve heard both here and 

today is, we don’t know a lot about the incubation period, but 

there’s a potential especially if there’s a transmission through sexual contact that the incubation period could actually be much 

longer. So you might—one might, for example, in terms of public 

health advice, advise a woman who is of childbearing age that 

there could potentially be a year and a half during which you really 

should not engage in sexual contact. Is that true? 

Ms. ERNST. Well, I think we don’t really know exactly yet how 

long the virus can persist in semen. As Dr. Presley was saying, 

there has been some evidence up to 3 months after the infection 

was thought to occur. I would suggest that if possible—I know that 

the resources are really difficult—to follow up each individual man 

until he screens negative, but that’s one potential possibility. The 

other possibility is that we do have some research that’s ongoing 

that I have heard of that they are following cohorts of men who are 

return travelers to really identify what is sort of that average time 

frame in which they can harbor the virus in their semen. 

Ms. EDWARDS. I guess, you know, if there’s 3 months and then 

add to that a 9-month pregnancy, that is a long window of time, 

and so I think it begs the question of how it is that we’re advising 

people of childbearing age who’ve traveled to those regions what 

they need to think about. I leave it at that. 

Chairman SMITH. Thank you, Ms. Edwards. 

That concludes our hearing today. We thank you for your expert 

testimony. This has been one of the more interesting hearings that 

we’ve had. You all are experts in certain areas and all of those 

areas were of interest to members of the Committee today. So 

thank you all again. We may be back in touch, and I should also 

say that members have two weeks to submit questions to you all. 

You heard the comments today, how many questions went unanswered, so you may get some more questions in the next couple of 

weeks. 

Thank you all again, and we stand adjourned. 

[Whereupon, at 12:15 p.m., the Committee was adjourned.] 

(87) 

Appendix I 

ANSWERS TO POST-HEARING QUESTIONS
88 

ANSWERS TO POST-HEARING QUESTIONS

Responses by Dr. Kacey Ernst 
89 
90 
91 
92 
93 
94 
95 
96 
97 
98 
99 
100 

Responses by Dr. Daniel Neafsey 
101 
102 

Responses by Dr. Steven Presley 
103 
104 
105 

Responses by Mr. Hadyn Parry 
106 

Æ