Health Hazard Evaluation Report 2011-0105-3173 Page 1

Evaluation of Zoonotic Disease and 

Exposures in Persons Working with Marine 

Mammals

Report No. 2011-0105-3173

April 2013

John Gibbins, DVM, MPH

R. Todd Niemeier, MS, CIH

Marie A. de Perio, MD

Charles Mueller, MS

U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health
Page 2 Health Hazard Evaluation Report 2011-0105-3173

Contents

Highlights...............................................i

Abbreviations ..................................... iv

Introduction......................................... 1

Methods ............................................... 2

Results .................................................. 4

Discussion .......................................... 11

Conclusions........................................ 15

Recommendations............................. 16

Appendix A ........................................ 19

Appendix B......................................... 22

Appendix C......................................... 24

References.......................................... 26

Acknowledgements........................... 31

The employer is required to post a copy of this report for 30 days at or near the 

workplace(s) of affected employees. The employer must take steps to ensure 

that the posted report is not altered, defaced, or covered by other material.

The cover photo is a close-up image of sorbent tubes, which are used by the HHE 

Program to measure airborne exposures. This photo is an artistic representation that may 

not be related to this Health Hazard Evaluation.
Health Hazard Evaluation Report 2011-0105-3173 Page i

We evaluated the exposure of 

marine mammal employees and 

volunteers to zoonotic diseases 

by giving them a questionnaire; 

collecting blood samples 

for serology; and collecting 

environmental samples. Even 

though we found little evidence 

of past infection in these people, 

they may still get zoonotic 

infections. We recommended 

improved engineering controls 

in the facility, improved personal 

protective equipment use, and 

enhanced training for employees 

and volunteers. 

Highlights of this Evaluation

The Health Hazard Evaluation Program received a request from a marine mammal rescue and 

rehabilitation center in California. Managers were concerned about the potential exposure of 

employees and volunteers to zoonotic diseases. Zoonotic diseases can be transmitted from 

animals to humans.

What We Did

● We evaluated the main facility and a triage facility in June 2011.

● We surveyed employees and volunteers, which included a questionnaire and serologic 

tests for evidence of past infection with three bacteria that cause zoonotic disease.

● We observed work practices and personal 

protective equipment use at both facilities.

● We took ventilation measurements in the 

headquarters laboratory and harbor seal building.

● We collected air, surface, and bulk dust 

samples for C. burnetti, one of the bacteria 

that cause zoonotic disease, at both facilities.

What We Found

● We observed some work practices that may lead 

to a higher risk of exposure to zoonotic diseases.

● Our evaluation of the blood samples of the 

213 participants found little evidence of past 

infection of employees and volunteers with the 

organisms that cause leptospirosis, brucellosis, 

or Q fever.

● All but one of the 130 environmental samples 

collected were negative for C. burnetii.

● Some employees and volunteers were not wearing the correct personal protective equipment.

● The biological safety cabinet in the headquarters laboratory did not have enough airflow.

● When the ventilation system in the harbor seal area was turned on, air flowed from the 

harbor seal intensive care unit to other areas of the building. This could lead to a higher 

risk of exposure to zoonotic agents.

 What the Employer Can Do

● Provide initial training for all volunteers and employees on hand washing, proper 

personal protective equipment use, and their risks of infection. Provide refresher 

training at least twice per year.

● Post more signs about hand washing at all facilities.
Page ii Health Hazard Evaluation Report 2011-0105-3173

 What the Employer Can Do (continued)

● Restrict the number of people at necropsies to limit potential exposure to zoonotic agents.

● Update the respiratory protection program to include facility employees and volunteers 

who work in the necropsy area.

● Develop a policy to ensure guest researchers who participate in necropsies are enrolled 

in their organization’s respiratory protection program.

● Require use of N95 respirators in addition to standard personal protective equipment 

during necropsy procedures that generate aerosols or when the likelihood of exposure 

to zoonotic agents is high.

● Remove carpet from the triage building and replace it with a nonporous surface.

● Do not house harbor seal pups in the harbor seal intensive care unit if they are 

suspected of having Q fever. House harbor seal pups suspected of having Q fever 

outside, ideally isolated from other harbor seal pups.

● Make sure that the biological safety cabinets in the headquarters laboratory are certified 

yearly and meet minimum flow requirements.

What Employees Can Do

● Wash your hands after exposure to animals or animal areas, even if you were 

wearing gloves.

● Use personal protective equipment that matches job duties.

● Do not wear personal protective equipment in areas in the triage building where people 

eat or drink.

● Do not eat or drink in the chart room or other areas where people wear personal 

protective equipment.

● Report any signs and symptoms of a possible zoonotic infection to your supervisor 

and seek medical care. Tell your healthcare provider about your duties and exposure to 

marine mammals.
Health Hazard Evaluation Report 2011-0105-3173 Page iii

Mention of any company or product does not constitute endorsement by NIOSH. In 

addition, citations to websites external to NIOSH do not constitute NIOSH endorsement 

of the sponsoring organizations or their programs or products. Furthermore, NIOSH is not 

responsible for the content of these websites. All web addresses referenced in this document 

were accessible as of the publication date of this report.
Page iv Health Hazard Evaluation Report 2011-0105-3173

Abbreviations

BSC Biological safety cabinet

BSL Biosafety level 

CDC Centers for Disease Control and Prevention

CFR Code of Federal Regulations

DNA Deoxyribonucleic acid

ELISA Enzyme-linked immunosorbent assay

fpm Feet per minute

ft2 Square feet

HHE Health hazard evaluation

ICU Intensive care unit

IFA Indirect fluorescent antibody

IgG Immunoglobulin G

IgM Immunoglobulin M

MAT Microagglutination test

NAICS North American Industry Classification System

NASPHV National Association of State Public Health Veterinarians 

NIOSH National Institute for Occupational Safety and Health

OSHA Occupational Safety and Health Administration

PCR Polymerase chain reaction

PPE Personal protective equipment

Spp. Species
Health Hazard Evaluation Report 2011-0105-3173 Page 1

Introduction 

The Health Hazard Evaluation (HHE) Program received a request from managers at a marine 

mammal rescue and rehabilitation center in California. The request concerned the potential 

for exposure of employees and volunteers to the bacterial pathogens responsible for the 

zoonotic diseases, Q fever (Coxiella burnetii), brucellosis (Brucella spp.), and leptospirosis 

(Leptospira spp.). These bacterial pathogens, most commonly associated with ruminants such 

as cattle, sheep, and goats, are also known to infect marine mammals, but the prevalence of 

infection in marine mammals and people who work with them is not known. 

In June 2011, National Institute for Occupational Safety and Health (NIOSH) investigators 

visited the center. During the visit, we met with employer, employee, and volunteer 

representatives to discuss the HHE request. We provided informational fact sheets and 

website links about Q fever, brucellosis, and leptospirosis. We observed workplace conditions 

and work processes and practices. We also spoke with employees and volunteers about their 

job duties. We focused our evaluation on work activities with potential exposures to animals 

or animal pathogens. We collected questionnaire and serologic data for participants and took 

environmental samples. In addition to our evaluation at the headquarters facility, part of our 

team traveled to a satellite triage center to enroll participants in the evaluation and collect 

environmental samples. 

Marine Mammal Rescue and Rehabilitation Center 

At the time of the evaluation, the center was a nonprofit veterinary rehabilitation hospital 

and educational center focused on the rescue, treatment, and rehabilitation of sick or injured 

marine mammals. As many as 200 animals at a time were cared for at its multiple facilities, 

which treated 1,000 animals each year. The center most commonly housed California sea 

lions, harbor seals, and elephant seals, although dolphins, porpoises, otters, and other species 

were sometimes cared for as well. Although clinically diagnosed cases of Q fever and 

brucellosis were reportedly rare at the center, mammals, especially sea lions, were routinely 

diagnosed with leptospirosis, on the basis of clinical judgment or laboratory diagnosis. 

Additional information about the epidemiology and clinical characteristics of these bacterial 

agents in marine mammals and humans is available in Appendices A and B.

The center’s facilities included the headquarters facility and three triage facilities along the 

California coast. These triage facilities assessed the health status of rescued animals and 

temporarily held animals for release or transport to the headquarters for further treatment.

The headquarters facility had approximately 35 paid employees and 200 regular volunteers. 

Employees’ job tasks included office work; necropsies; animal handling; capturing sick or 

wounded animals from the beach, water, and docks; releasing animals back into the wild; 

clinical laboratory work; and facilities maintenance. In addition, employees oversaw the 

work of volunteers. Volunteers did numerous jobs including office work; staffing the gift 

shop; educational outreach; preparing animal food; administering medication; handling 
Page 2 Health Hazard Evaluation Report 2011-0105-3173

animals; cleaning pens; capturing sick or wounded animals from the beach, water, and docks; 

and releasing animals back into the wild. 

Volunteers at the headquarters facility typically worked one shift a week; shifts usually ran 

from 7 a.m. to 3 p.m. (day shift) and 6 p.m. to 11 p.m. (night shift). Shift length and number 

of volunteers per shift varied on the basis of the number of animals at the facility. Several 

hundred additional volunteers over a 600-mile range, from Mendocino County, California, 

through San Luis Obispo County, California, were responsible for animal rescue, triage, 

transportation, release, and education.

Methods

The purpose of our evaluation was to (1) assess the occupational risk of workers and 

volunteers to Coxiella burnetii (C. burnetii), Brucella spp., and Leptospira spp.; (2) assess 

the center’s engineering, administrative, and personal protective equipment (PPE) controls; 

and (3) make recommendations to improve related occupational health practices.

We conducted a serologic survey of center employees and volunteers, observed work 

practices and PPE use at the headquarters facility and one triage facility, took ventilation 

measurements in the laboratory and harbor seal area, and collected environmental samples in 

several areas around the headquarters facility and a triage facility. 

Serologic Survey

Using a cross-sectional study design, we invited all employees and volunteers 18 years 

old and older working at the headquarters facility and triage facility on the dates of our 

evaluation to participate in our serologic survey, which consisted of a questionnaire and 

serum sample. Other volunteers who were not working the week of our visit were also invited 

to participate. We counted those who volunteered at the headquarters facility and triage 

facilities or also participated in beach rescue as headquarters volunteers. The questionnaire 

included personal characteristics; relevant medical history; work duties at the facility and 

at other job sites, in the case of volunteers and part-time employees; work history; and risk 

factors for Q fever, brucellosis, and leptospirosis.

After giving informed consent, participants provided a serum sample for us to determine the 

prevalence of immunologic evidence of past infection with C. burnetii, Brucella spp., and 

Leptospira spp. All serum samples were analyzed at the laboratories within the Centers for 

Disease Control and Prevention (CDC) Rickettsial Zoonoses Branch and Bacterial Special 

Pathogens Branch in Atlanta, Georgia. Details about serologic laboratory methods are 

available in Appendix C.

To determine seroprevalence, the following case definitions were used:

● Brucella seropositivity was defined as a Brucella total antibody titer ≥ 1:160 by the 

Brucella MAT. 
Health Hazard Evaluation Report 2011-0105-3173 Page 3

● Leptospirosis seropositivity was defined as a Leptospira agglutination titer ≥ 1:100 by 

the Leptospira MAT. 

● Q fever seropositivity was defined as a phase I or phase II immunoglobulin G (IgG) 

titer ≥ 1:32 by IFA for IgG antibodies. 

Participants below these cutoff levels either had not been infected with the organism in 

the past, or their titer was too low to determine if they were previously infected; titers can 

wane over time in some individuals. Phase I IgG antibody levels for C. burnetii ≥ 1:800 

were considered suggestive of chronic Q fever infection. Participants were notified of their 

individual serological results by letter in September 2011. 

SAS Version 9.2 software (SAS Institute Inc., Cary, North Carolina) was used for statistical 

analysis. We calculated prevalence ratios and used 2X2 analyses with Fisher’s exact test 

to evaluate possible relationships between C. burnetii seropositivity and participants’ 

characteristics or exposures. Prevalence ratios greater than 1 indicate that the participants 

with the characteristic or exposure had a prevalence of seropositivity greater than that for 

the participants without the characteristic or exposure. Results with P values ≤ 0.05 were 

considered statistically significant. 

Observation of Work Practices

To understand potential exposures to zoonotic agents, we observed work practices at the 

headquarters facility and one of the triage facilities. We observed employees and volunteers 

during daily cleaning and feeding in animal pens, necropsies, maintenance activities, 

laboratory activities, and animal handling and transportation. We noted PPE use among 

employees and volunteers during these work activities.

Ventilation Assessment

We evaluated the airflow in two biological safety cabinets (BSCs) in the laboratory at the 

headquarters facility. We used a TSI VelociCalc® Plus air velocity meter, model 8386A (TSI, 

Inc., Shoreview, Minnesota) to measure air velocity at the face of each BSC. We collected 

equally spaced air velocity measurements at approximately 12-inch intervals across the face 

of the BSC in the microbiology laboratory and at approximately 18-inch intervals across 

the face of BSC in the clinical laboratory. In addition, we used smoke tubes to visualize 

the direction of airflow in the harbor seal intensive care unit (ICU) (Gastec Corporation, 

Kanagawa, Japan).

Environmental Sampling

We collected 37 air samples including 23 personal breathing zone and 14 area samples, 69 

surface samples (25 vacuum samples for porous surfaces and 44 sponge wipes for nonporous 

surfaces), and 10 bulk dust samples to determine the presence of C. burnetii in several areas 
Page 4 Health Hazard Evaluation Report 2011-0105-3173

Table 1. Frequency of work practices reported by employees and volunteers who also reported 

caring for marine mammals

Number (%) of participants, n = 211–213*

Work practice Always Most of the time Some of the time Never

Wash hands before eating 194 (91) 17 (8) 2 (1) 0 (0)

Change clothes before eating 63 (30) 37 (17) 53 (25) 59 (28)

Shower before eating 7 (3) 10 (5) 38 (18) 158 (74)

Change clothes before leaving work 61 (29) 17 (8) 55 (26) 80 (38)

Shower before leaving work 2 (1) 5 (2) 16 (8) 190 (89)

PPE use:

Gloves 154 (73) 47 (22) 10 (5) 0 (0)

Rubber boots 146 (69) 41 (19) 23 (11) 3 (1)

Raincoat/waterproof suit 88 (41) 58 (27) 52 (24) 15 (7)

*Sample sizes vary because of missing values.

within the headquarters facility and triage facility. Details of environmental sampling and 

analysis methods are available in Appendix C. 

Results 

Serologic Survey

The 222 participants who completed our questionnaire included 35 paid employees, 184 

volunteers, and 3 participants who reported working both as a paid employee and a volunteer. 

Among the 222 participants, 198 (89%) worked at the headquarters facility, 24 (11%) worked 

at the triage facility, and 213 (96%) reported ever caring for or handling marine mammals. 

The median age of participants was 45 years (range: 18–77 years). Of the 222 survey 

participants, 164 (74%) were female. Survey participants had worked or volunteered at the 

headquarters facility or triage facility for a median of 2.4 years (range: 2 days–35 years), a 

median of 40 weeks per year (range: 1–52 weeks per year), and a median of 8 hours a week 

(range: 2–70 hours per week). In addition, 213 (96%) reported caring for marine mammals at 

the center. Eleven participants reported being veterinarians.

The work and PPE practices of the 213 survey participants who reported caring for marine 

mammals are shown in Table 1. Of these 213 participants, 194 (91%) reported always 

washing their hands before eating at work, while 61 (29%) reported always changing their 

clothes before leaving work. Regarding PPE use, none of these 213 participants reported 

never wearing gloves, 3 (1%) reported never wearing rubber boots, and 15 (7%) reported 

never wearing a raincoat or waterproof suit while working at the center. Only 154 (73%) 

reported always wearing gloves, and 88 (41%) reported always wearing raincoats/waterproof 

suits. However, our discussions with employees and volunteers as well as observations of 
Health Hazard Evaluation Report 2011-0105-3173 Page 5

work tasks revealed that some participants did additional tasks at the facility that did not 

involve direct animal care or require PPE use, such as giving tours, participating in meetings 

and rounds, and office work. 

Of the 77 participants who reported having contact with dead marine mammal tissues, fluids, 

and blood during necropsies, 46 (60%) reported never wearing goggles, 42 (55%) reported 

never wearing masks, and 68 (88%) reported never wearing respirators during their work. 

Of the 222 participants who completed our questionnaire, 213 (96%) consented and provided 

a serum sample. All 213 participants providing a serum sample were considered negative for 

brucellosis infection using the Brucella total antibody titer of ≥ 1:160. Thirty-eight (18%) 

participants had total antibody titers between 1:20 and 1:80, which might indicate past 

exposure with Brucella spp., and 175 (82%) had negative Brucella titers. None of the 221 

participants reported ever being diagnosed with brucellosis.

Two (1%) participants had titers that were considered positive for past leptospirosis 

infection. None of the 221 participants reported ever being diagnosed with leptospirosis. 

The two seropositive participants were part-time volunteers who had been at the center for 

at most 2 months. Both were female, worked in the topside area, and reported exposures to 

other potential sources of leptospirosis including working with animals before working at 

this center and participating in outdoor water recreational activities such as water sports, 

swimming, and paddling, excluding swimming pool use. Of the participants, 50% also 

reported working with animals before working at this center, and 92% reported participating 

in outdoor water recreational activities. 

Nine (4%) participants demonstrated antibody titers to C. burnetii that indicated past 

infection with Q fever. None had titers suggestive of chronic Q fever infection. The median 

age of the nine seropositive participants was 40 years (range: 27–60 years); eight were 

female. Three were paid employees, and six were volunteers. Eight reported ever caring for 

or handling marine mammals at the center. Only one participant, a veterinarian, reported ever 

being diagnosed with Q fever, and this occurred in 2004 prior to working at the center.

Characteristics associated with C. burnetii seropositivity are shown in Table 2. 

Characteristics and exposures that were significantly associated with positive serology 

for C. burnetii were being a veterinarian (prevalence ratio: 11.6, P < 0.01); self-reported 

exposure to feral swine blood or fluids in past year (prevalence ratio: 11.9, P = 0.01); and 

consumption of raw (unpasteurized) dairy products, such as raw milk or cheese, within the 

last year (prevalence ratio: 4.4, P = 0.03). 
Page 6 Health Hazard Evaluation Report 2011-0105-3173

Table 2. Frequency and prevalence of C. burnetii seropositivity in participants

Characteristic or exposure Participants with 

characteristic 

or exposure 

Seropositive (%)

Participants without 

characteristic 

or exposure 

Seropositive (%)

Prevalence 

ratio

P value*

Female 8/157 (5) 1/56 (2) 2.9 0.45

Veterinarian 4/11 (36) 5/159 (3) 11.6 < 0.01

Cared for or handled 

pinnipeds (seals, fur seals, 

sea lions)

8/204 (4) 1/9 (11) 0.4 0.33

Cared for or handled 

cetaceans (whales, 

dolphins, porpoises

4/78 (5) 4/133 (3) 1.7 0.47

Cared for or handled sea 

otters

3/58 (5) 6/154 (4) 1.3 0.71

Contact with live marine 

mammals, tissues, or blood

9/200 (5) 0/13 (0) Undefined > 0.99

Contact with dead marine 

mammals, tissues, fluids 

and blood

7/162 (4) 2/51 (4) 1.1 > 0.99

Contact with pregnant/

newborn/birth products 

from marine mammal

7/132 (5) 2/81 (2) 2.1 0.49

Clean or repair equipment 

or enclosures

7/197 (4) 2/16 (13) 0.3 0.14

Ever lived within 5 miles of 

sheep, goat, cattle

5/84 (6) 4/129 (3) 1.9 0.32

Exposed to feral swine 

blood or fluids in past 

year

2/5 (40) 7/208 (3) 11.9 0.01

Consumed raw dairy in 

past year

5/47 (11) 4/166 (2) 4.4 0.03

*P values (Fisher’s exact test) < 0.05 shown in bold text.

Observation of Work Practices and Personal Protective 

Equipment Use 

Pen Cleaning and Animal Feeding

At the time of our evaluation, the headquarters facility had a topside area that contained 18 

outdoor pens to house elephant seals and sea lions. In this area, volunteers usually worked 

in groups of two or three. All of the animal pens were cleaned weekly or when animals were 

permanently moved from the pens. A 10% household bleach solution was poured onto the 

concrete and scrubbed with a push broom (Figure 1). After scrubbing, the area was rinsed 

with water via a hose. Walkways within the pen areas were disinfected daily. Individuals 
Health Hazard Evaluation Report 2011-0105-3173 Page 7

working in this area wore chest-high waterproof overalls, rubber boots, and reusable rubber 

or disposable powder-free natural latex gloves for all activities. 

We observed volunteers taking their breaks, eating, 

and drinking in the chart room. We also observed 

individuals entering the chart room while still 

wearing overalls and boots. Some volunteers at 

the headquarters facility told us that they did not 

always wash their hands after handling animals 

because they wore gloves during animal handling 

procedures.

A separate area of the headquarters facility housed 

harbor seals. This area consisted of outdoor and 

indoor caged areas. The outdoor area had 10 small 

cages without pools to house individual harbor 

seals and four larger pens with concrete pads 

and pools to house groups of harbor seals. Three 

additional pens with pools were adjacent to the 

topside area for animals ready for release (Figure 

2). The harbor seal area was also served by a 

separate building that housed a chart room, fish 

kitchen, x-ray room, surgery suite, and harbor seal 

ICU. The harbor seal ICU had 11 indoor cages to 

house abandoned harbor 

seal pups until they were 

well enough to be moved 

outside. Volunteers in this 

area usually worked in 

groups of up to five. The 

same cleaning and feeding 

methods used in the topside 

area were used in this area. 

We observed the same use 

of PPE in this area as in 

topside. Boot wash stations 

that contained a 10% 

household bleach solution 

were located throughout 

both areas.

Figure 1. Volunteer cleaning an animal pen 

at the headquarters facility wearing PPE. 

Figure 2. Volunteers feeding harbor seal pups at the headquarters 

facility.
Page 8 Health Hazard Evaluation Report 2011-0105-3173

Triage Facility 

The triage facility had eight outdoor pens and four indoor pens in a garage area attached 

to a one-story office building. The triage facility was staffed by one employee and several 

volunteers. The office building had a common area, kitchen, bathroom, three offices, and a 

separate kitchen for animal medication and food processing. The office area was carpeted 

throughout, except in the garage and animal kitchen. Only one animal was present at the triage 

facility during our evaluation, and it was housed in an outdoor pen. PPE worn by volunteers 

and employees at the triage facility depended on the work activities. On the day of our 

evaluation, employees and volunteers wore leather work gloves or disposable powder-free 

natural latex gloves while handling the sea lion or its cage and rubber boots while performing 

wet work. According to employees and volunteers, they wore chest-high waterproof overalls 

when needed. They reported that they sometimes wore the overalls in the office area after 

handling the animals or cleaning cages. 

Animal Transportation

At the time of our evaluation, when animals were rescued from the beach, they were 

corralled into crates using wooden planks. The crates were placed into either the bed of a 

pickup truck or the back of a cargo van, and the animals were then transported to the main 

facility or a triage facility (Figure 3). The cargo vans had passenger compartments that 

were separated from the cargo area by a metal plate with an access door. The air was shared 

between the two areas of the van. We observed a van delivering a sea lion pup housed in a 

crate and noted extensive fecal contamination in the back of the van after the animal was 

removed. According to volunteers, the vans were usually cleaned with water if they were 

heavily soiled. We did not observe this cleaning activity. The inside of the crate was also 

heavily soiled with fecal matter. 

After the sea lion was 

removed from the crate, 

the crate was washed with 

water and disinfected with 

a 10% household bleach 

solution. The volunteers 

removing the crate from 

the van wore powder-free 

natural latex or leather 

work gloves when handling 

and washing the crate. 

Rehabilitated animals 

housed at the facility were 

often released in groups. 

Animals were placed in 

crates, loaded into the back Figure 3. Animals to be released are loaded into a cargo van at the 

headquarters facility. 
Health Hazard Evaluation Report 2011-0105-3173 Page 9

of pickup trucks and vans, and driven approximately 2 hours to a secluded beach for release. 

Some personnel wore powder-free natural latex gloves or work gloves when handling the 

animal cages during the release; others wore no gloves. Personnel wore no other PPE during 

the release.

Filter Room Maintenance

The salt water system that provided pool water for the marine mammals at the facility 

was a 100% recirculating system. The filtration room was in a completely enclosed 

decommissioned underground missile silo. Water was circulated from the pools to drum 

filters, sand filters, ozone treatment, and foam fractionators. After filtration, the water 

was sent to storage tanks, where it was kept until it was needed to refresh the pools. The 

drum filters were opened and sprayed once per week with a water lance. Sand filters and 

foam fractionators were cleaned one or two times per year with a hose or water lance. 

Though we did not see these activities, according to maintenance staff, nitrile gloves were 

typically worn during cleaning activities. Though maintenance staff did not wear respiratory 

protection during cleaning activities in the filtration room, some maintenance staff were 

included in the respiratory protection program. The written respiratory protection program 

included medical evaluations and fit testing with half-mask air purifying respirators 

equipped with particulate and vapor cartridges for wear during other work tasks such as 

painting or dust generating activities. 

Necropsy Procedures

Necropsies were performed at the headquarters 

facility in a room approximately 12 feet wide 

by 20 feet long (Figure 4). A single exhaust 

fan located approximately 20 feet above the 

necropsy table was operational but rarely 

used. One wall of the room consisted of a 

large garage door that opened to the outside. 

Necropsies were usually performed with this 

garage door open. The necropsy room also 

had an adjacent changing room. A foot bath 

containing a 0.26% calcium hypochlorite 

solution was located between the changing 

room and the necropsy area. We observed 

employees wearing short-sleeved scrubs, 

aprons, rubber boots, and a single layer of 

powder-free latex gloves during all necropsy 

procedures described below. NIOSH-approved 

N95 filtering facepiece respirators were 

available but not used by employees during 

necropsy procedures. According to employees, 

N95 filtering facepiece respirators were 

Figure 4. Veterinary staff conducting a necropsy 

on two marine mammals at the headquarters 

facility. 
Page 10 Health Hazard Evaluation Report 2011-0105-3173

used if a suspected zoonotic disease hazard was identified by the necropsy team during the 

procedure. Employees who conducted necropsy procedures had not been fit tested and were 

not included in the respiratory protection program. 

During one of the necropsies we observed, guest researchers from a local university collected 

a sea lion brain. A bone saw was used to open the skull, which generated visible tissue and 

bone-related aerosols. The team wore surgical masks, short-sleeved scrubs, aprons, rubber 

boots, and powder-free latex gloves. Headquarters employees observed this procedure in the 

necropsy room while wearing similar PPE. Neither the university team nor the headquarters 

employees wore respiratory protection during this procedure. Water sprayed from a hose was 

used to wash away blood during the necropsy. This practice could generate aerosols in the 

work area. 

After the necropsies, carcasses were loaded into drums for offsite disposal. The drums were 

placed on the floor next to the necropsy table, and carcasses were pushed from the table into 

the drums, creating a spray of blood. After gross blood contamination was washed down the 

drains with water, the necropsy room was scrubbed with a 10% household bleach solution 

and dishwashing detergent.

Laboratory

The headquarters facility had a clinical and microbiology laboratory in adjacent rooms that 

was staffed by four employees and four volunteers. The laboratory had clinical diagnostic 

and research capabilities. Several pieces of equipment processed clinical (blood, urine, fecal) 

specimens. The laboratory was served by two BSCs. The clinical laboratory had a Class II 

B2 cabinet that was exhausted to the outside and was used for formalin fixing and bagging 

tissue samples. The microbiology laboratory had a Class II A2 cabinet used for plating 

culture samples. This cabinet recirculated air back into the room after passing through a highefficiency particulate air filter. The microbiology laboratory also had a cabinet that was used 

to store formalin-fixed tissue samples. This cabinet was fitted with mechanical ventilation 

and was exhausted to the outside. Other laboratory processes including hematology, 

blood smears, and blood chemistry were processed outside the BSCs. In the microbiology 

laboratory, culture plates were opened and counted on an open bench top (not in the BSC). 

Further manipulation of the culture plates and any other aerosol generating activities were 

done in the BSC. During laboratory procedures, we observed employees wearing powderfree natural latex gloves and, in some cases, lab coats. 

Ventilation Assessment

Table 3 summarizes the air velocity measurements and results of smoke tube testing on the 

BSCs. The average face velocity was 113 feet per minute (fpm) for the clinical laboratory 

BSC and 92 fpm for the microbiology laboratory BSC. Both BSCs demonstrated effective 

capture of smoke at the hood face. The testing and certification tag on the BSC in the clinical 

laboratory indicated that recertification had been due in November 2009. The testing and 

certification tag on the BSC in the microbiology laboratory indicated that the BSC was up to 
Health Hazard Evaluation Report 2011-0105-3173 Page 11

Table 3. Evaluation of the biological safety cabinets at the 

headquarters laboratory*

Location Area of face (ft2) Air velocity (fpm)

Range Mean

Clinical laboratory 

BSC

1.9 85–146 113

Microbiology 

laboratory BSC

2.3 36–144 92

*Air velocity and smoke tube measurements were taken at the 

face of the BSCs.

date, and that recertification was due in June 2012. 

The fixed tissue storage cabinet had two relief vents at the bottom of the cabinet doors to 

provide airflow through the cabinet and prevent buildup of formaldehyde vapors. Smoke tube 

testing revealed that minimal airflow was entering the cabinet. Tissue samples stored inside 

were blocking the relief vents. 

The harbor seal area was served by a multi-zone, variable air volume air handling unit that 

recirculated return air from all areas in the building and mixed it with outdoor air. (The 

percent outdoor air unknown). The ventilation system was used approximately 10 days per 

year when additional heating or cooling was required. Typically, the building was naturally 

ventilated by open windows and doors. When the ventilation system was running, air flowed 

from the harbor seal ICU to the adjacent hallway leading to other areas within the building. 

When the ventilation system was turned off, air movement between the harbor seal ICU and 

the adjacent hallway was neutral.

Environmental Sampling

All 37 general area and personal breathing zone air samples were negative for C. burnetii. 

We collected 69 surface wipe samples and 10 bulk dust samples; one collected on a light 

fixture in the headquarters topside fish kitchen was positive for C. burnetii. All other surface 

samples and bulk dust samples were negative for C. burnetii. 

Discussion

Our serologic evaluation revealed little evidence of past infection of employees and 

volunteers with leptospirosis, brucellosis, or Q fever. The two participants with titers that met 

the case definition for evidence of past infection with leptospirosis had worked at the center 

for at most 2 months, and had other exposures associated with leptospirosis infection, which 

makes infection from sources outside the facility more likely. 

Brucellosis titer interpretation and evidence of past infection is complicated because a titer of 

≥ 1:160, compatible clinical symptoms, and probable exposure are typically used to diagnosis 
Page 12 Health Hazard Evaluation Report 2011-0105-3173

a clinical case of brucellosis. 

C. burnetti seroprevalence was found to be 4% among those we tested, and this is 

comparable to the 3% seroprevalence estimated for the general U.S. adult population 

[Anderson et al. 2009]. In our analysis, we found that characteristics significantly associated 

with prior exposure to C. burnetii included ingestion of raw, unpasteurized dairy products in 

the past year, contact with feral swine blood and/or fluids in the past year, and a veterinary 

occupation. None of these risk factors necessarily implicate marine mammals or marine 

mammal rescue work, as they may be unrelated to marine mammals. Raw milk from infected 

cows contains organisms and may serve as a transmission route to humans [Heymann 2004], 

and a veterinary occupation is a well-recognized risk factor for C. burnetii seropositivity. 

Studies of U.S. veterinarians estimate a 22% seroprevalence for C. burnetii [Whitney et al. 

2009a]. Little is known about the virulence of marine mammal C. burnetii strains in humans. 

However, case reports have associated human infections with a variety of other bacterial, 

viral, and parasitic zoonotic agents in people with occupational exposure to marine mammals 

in field and laboratory settings [Hunt et al. 2008]. 

Our environmental sampling results suggest a very low environmental load of C. burnetii 

at both facilities at the time of our evaluation. C. burnetii in its spore like form is highly 

resistant to desiccation, and can survive for extended periods in the environment [van 

Woerden et al. 2004]. We sampled in infrequently cleaned areas and collected dust from 

vacuum cleaner bags to maximize our chances of detecting C. burnetii, yet we detected C. 

burnetii in only one sample. Either Q fever infections are uncommon in the marine mammal 

population served by the facilities or cleaning methods are effectively controlling C. burnetti

contamination. However, in a recent study, C. burnetii seropositivity was detected in 34% of 

215 Pacific harbor seals sampled in the Pacific Northwest [Kersh et al. 2012]. For C. burnetii, 

infection is most commonly associated with dry and dusty environments, as these conditions 

are more amenable to the bacterium becoming airborne and increasing the likelihood that 

the bacterium is spread to areas away from the source of contamination (i.e. the marine 

mammal). The marine environment, specifically the one in this evaluation, is neither dry 

nor dusty, and it is regularly cleaned. This may limit the potential for the bacterium to be 

transmitted to humans and surfaces.

Though the serologic survey revealed little evidence of past infection with the three zoonotic 

agents, we did observe work practices that could increase risk for exposure and infection 

with zoonotic agents. The NASPHV has guidelines for standard precautions for zoonotic 

disease prevention in veterinary personnel [NASPHV 2010]. The guidelines include infection 

control measures, PPE for specific types of tasks (including animal handling and necropsy), 

and other information. These guidelines are appropriate for the center’s veterinary personnel, 

other employees, and volunteers with potential exposure to zoonotic agents. 

In the pen areas at the headquarters facility and triage facility, volunteers and employees 

wore appropriate PPE, demonstrated good cleaning techniques of pens, and used foot baths 

frequently when walking around the pen areas. However, some volunteers at the headquarters 

facility reported not washing their hands after handing animals because they had been 
Health Hazard Evaluation Report 2011-0105-3173 Page 13

wearing gloves. These anecdotal reports were supported by our survey results, which 

revealed that 9% of participants who reported caring for marine mammals reported that they 

did not always wash their hands before eating. NASPHV states that the use of gloves is not 

a substitute for hand washing because gloves can have undetected tears. Additionally, hands 

can become contaminated when removing gloves. 

At the triage facility, we observed that volunteers and employees wore street shoes while 

working with animals and cleaning cages and pens. Though employees and volunteers used 

foot baths to decontaminate their street shoes, shoes with porous materials (such as gym 

shoes or leather boots) are difficult to fully decontaminate. Rubber boots were also reportedly 

available at the triage facility and were used if significant wet work was anticipated. 

At both facilities, we either observed or were told by volunteers that PPE was worn in chart 

rooms or other areas where individuals ate or drank. Additionally, the triage facility was 

carpeted in most indoor areas. Because carpeting is a porous surface, it is difficult to properly 

clean and sanitize. 

Our survey results showed that 95% of 211 participants caring for marine mammals reported 

wearing gloves at least most of the time during their work at the facility, which suggests 

good compliance with this practice. We observed that employees and volunteers mostly used 

powder-free natural rubber latex gloves at both facilities. Though latex gloves do provide an 

effective barrier against infectious agents, other glove materials including nitrile or vinyl are 

acceptable alternatives that can be used to minimize the potential for latex allergy [NASPHV 

2010]. NIOSH provides guidance on the potential hazards and recommendations on the use 

of natural latex gloves [NIOSH 1998].

The potential for exposure to infectious agents could be present when transporting animals 

from the beach via an enclosed van because the health status of these animals has not been 

fully evaluated. Using a pickup truck whenever possible may better protect staff from 

exposures to airborne infectious agents such as C. burnetti and Brucella spp. 

Our survey results showed that 77 participants reported ever having contact with dead marine 

mammal tissues, fluids, and blood during necropsies. These 77 participants included 49 

volunteers, 26 paid employees, and two participants who reported both. A majority of these 

participants reported they never wore gloves, masks, or respirators during their work. During 

the necropsies we observed at the main facility, we did not see volunteer participation. Also, 

managers told us that volunteers typically did not participate in necropsies at the facility, as 

they were performed by paid staff or guest researchers. It is possible that more volunteers 

reported being present at necropsies than expected because they may have participated in 

necropsies or tissue collection on the beach or at locations other than the main facility. In the 

necropsy area of the main facility, we observed that PPE for droplet exposure (such as a face 

shield, or goggles and face mask) was not worn by employees during necropsies, cleanup 

after the necropsies, or transfer of animal carcasses into drums. In addition, we observed the 

use of a bone saw to facilitate brain collection, which generated visible aerosols from tissue 
Page 14 Health Hazard Evaluation Report 2011-0105-3173

and bone; however, respiratory protection was not worn by those in the room. Employees 

reported that respiratory protection was only worn if a possible inhalation exposure hazard 

was recognized during a necropsy and that this occurred very rarely. At the time of our 

evaluation, employees working in the necropsy area were not included the respiratory 

protection program. NASPHV and CDC provide recommendations for the type of PPE that 

should be worn during animal necropsies if there is a high likelihood of exposure to zoonotic 

agents [NASPHV 2010; CDC 2012a].

In the laboratory, risk of exposures to biological agents appeared to be generally low. The lab 

functioned as a BSL 2 laboratory though CDC categorizes both C. burnetii and Brucella spp.

as Group 3 risk agents that might be present in a veterinary diagnostic laboratory. The facility’s 

director of veterinary science reported that no cases of Q fever or brucellosis infections had been 

diagnosed among animals housed at the facility. If these agents are encountered in laboratory 

specimens, CDC recommends manipulating them using BSL 3 work practices and equipment 

because these agents can cause serious infections as a result of inhalation exposure [CDC 

2012a]. Leptospira spp. is classified as a Group 2 agent and is recommended to be handled 

under less rigorous BSL 2 work practices and equipment [CDC 2012a]. 

The “Biosafety in Microbiological and Biomedical Laboratories, 5th edition” document 

provides information on the use of BSCs in the laboratory environment [DHHS 2009]. For 

Class II A2 and B2 BSCs, this document recommends that average air velocity across the 

face of a BSC be at least 100 fpm. The average air velocity that we measured at the BSC 

in the clinical laboratory (113 fpm) met this recommendation. However, the BSC in the 

microbiology laboratory had an average face velocity slightly below this recommendation 

(92 fpm), and in one location the velocity was only 36 fpm. The clinical laboratory BSC 

had not been certified since 2009, placing it out of the certification period recommended by 

this document and by the contractor that serviced the BSC at the facility. Relief vents on the 

formalin fixed tissue cabinet were blocked and could prevent proper exhaust of formaldehyde 

vapors, leading to increased exposures among laboratory staff. 

The ventilation system in the harbor seal area was rarely used. However, when it was turned 

on, it directed air from the harbor seal pup area to other areas of the building where the air 

was recirculated, which could potentially spread zoonotic agents. Even with this ventilation 

system turned off, natural ventilation could spread infectious agents throughout the building. 

Housing animals in outdoor pens whenever possible is the best option.

C. burnetii is very resistant to heat, drying, and most common disinfectants. Scott and 

Williams [2006] found that aqueous solutions containing C. burnetii in concentrations of 

108 organisms were not completely inactivated by 0.5% hypochlorite, 5% Lysol®, 5% 

formalin, or 2% Roccal® after 24 hours at 24 degrees Celsius. However, C. burnetii was 

completely inactivated within 30 minutes by either 70% ethanol, 5% chloroform, or 5% 

Enviro-ChemTM. Both Leptospira spp. and Brucella spp. are more susceptible to common 

disinfectants. Liquid antimicrobial products that can inactivate Leptospira spp. include a 1% 

bleach solution, iodine-based disinfectants, accelerated hydrogen peroxide, and quaternary 

ammonium compounds [Sykes et al. 2010]. For Brucella spp., pH amended bleach (mixture 
Health Hazard Evaluation Report 2011-0105-3173 Page 15

of 1 part household bleach [5.25% to 6.0%] to 1 part white vinegar to 8 parts water) is 

recommended [NRT 2011]. Further guidance on the use of pH amended bleach for Brucella 

spp. can be found in the National Response Team Quick Reference Guide for Brucella spp. at 

http://www.nrt.org/Production/NRT/NRTWeb.nsf/AllAttachmentsByTitle/A-1009WMDQRG

BrucellaSpecies/$File/120502_Brucella_QRG_Final.pdf?OpenElement. We understood that 

the facility used a 10% bleach solution made from calcium hypochlorite. This concentration 

will inactivate both Leptospira spp. and Brucella spp. but it is unclear if it will inactivate 

C. burnetii. Consideration should be given to the use of other recommended disinfectants if 

veterinary staff strongly suspects that a marine mammal may be infected with Q fever. This 

may be especially important in areas where there may be greater exposure to C. burnetii

containing blood and body fluids, such as surgical, necropsy, and laboratory settings, and 

when handling placental tissues or neonatal pups. 

Our evaluation was subject to some limitations. First, most of our participants were based 

at the headquarters facility. We were not able to include all employees and volunteers at the 

other satellite facilities and the stranding network. Therefore, our serologic survey results 

may not be generalizable to all employees and volunteers exposed to marine mammals. 

Second, serologic testing for Q fever and leptospirosis indicates if one has been infected at 

some point in the past, but these tests are unable to determine when infection occurred. It 

is also possible that antibody titers may wane over time, leading to false negative serologic 

results for remote infections. Third, because of limitations in laboratory capabilities, our 

environmental sampling was restricted to C. burnetii, and we were unable to determine 

environmental contamination with Brucella spp. and Leptospira spp. Finally, contact with 

infected birth products is thought to be a mode of transmission of C. burnetii, and harbor 

seals in this region of California typically give birth from February to April. Because our 

evaluation took place in late June, we may have been less likely to detect environmental 

contamination with C. burnetii because of the low numbers of harbor seals at the facility. 

Conclusions 

Our evaluation found little evidence of past infection on the basis of antibody titers for 

employees and volunteers exposed to marine mammals, suggesting a low occupational 

exposure to Q fever, leptospirosis, and brucellosis among this population. In addition, our 

environmental sampling suggests a very low environmental load of C. burnetti at both 

facilities at the time of our evaluation. However, prior studies have shown that marine 

mammals can have clinical illness or antibodies against the organisms that cause Q fever, 

brucellosis, leptospirosis, and other zoonotic infections, which may be transmitted to 

employees and volunteers caring for them. The fact that some participants had Brucella

titers indicating possible past infection and the finding of positive Q fever titers among 

some participants indicate that infection could have occurred while working with marine 

mammals at this or other facilities. Because leptospirosis is seen in animals routinely treated 

at this facility, precautions as discussed in our recommendations are important to protect 

worker health. Inappropriate work practices, insufficient PPE use, and engineering control 

deficiencies suggest that employees and volunteers were at risk for acquiring zoonotic 

infections.
Page 16 Health Hazard Evaluation Report 2011-0105-3173

Recommendations 

On the basis of our findings, we recommend the actions listed below. We encourage 

marine mammal rescue and rehabilitation facility to use a labor-management health and 

safety committee or working group to discuss our recommendations and develop an action 

plan. Those involved in the work can best set priorities and assess the feasibility of our 

recommendations for the specific situation at marine mammal rescue and rehabilitation facility. 

Our recommendations are based on an approach known as the hierarchy of controls. This 

approach groups actions by their likely effectiveness in reducing or removing hazards. In 

most cases, the preferred approach is to eliminate hazardous materials or processes and install 

engineering controls to reduce exposure or shield employees. Until such controls are in 

place, or if they are not effective or feasible, administrative measures and personal protective 

equipment may be needed. 

Engineering Controls

Engineering controls reduce employees’ exposures by removing the hazard from the process 

or by placing a barrier between the hazard and the employee. Engineering controls protect 

employees effectively without placing primary responsibility of implementation on the 

employee. 

1. Recertify the BSC in the clinical laboratory. CDC recommends annual recertification 

[CDC 2012a].

2. Recertify the microbiology laboratory BSC to ensure minimum airflow of 100 fpm 

across the face of the cabinet [DHHS 2009; CDC 2012a]. 

3. Rearrange items in the formalin laboratory storage cabinet to ensure that airflow 

through the relief vents is not blocked by items stored in the cabinet. Use visual smoke 

or another test, such as using a small piece of facial tissue (“tissue test”), to determine 

if air is moving into the cabinet. Evaluate this storage cabinet as part of the annual 

ventilation recertification process. 

4. Do not house harbor seal pups in the harbor seal ICU if Q fever infection is suspected. 

Develop a long-term solution that provides housing for these animals in an area that 

does not share ventilation with the harbor seal building. In the interim, do not use the 

ventilation system in the harbor seal area building when housing animals suspected 

of having Q fever within the harbor seal ICU. Air from this area is distributed to other 

areas of the harbor seal building. Also, keep the door between the harbor seal ICU and 

adjacent hallway closed when animals are housed in this area.
Health Hazard Evaluation Report 2011-0105-3173 Page 17

Administrative Controls

The term administrative controls refers to employer-dictated work practices and policies 

to reduce or prevent hazardous exposures. Their effectiveness depends on employer 

commitment and employee acceptance. Regular monitoring and reinforcement are necessary 

to ensure that policies and procedures are followed consistently.

1. Provide initial and semiannual refresher training on hand washing for all volunteers 

and employees. Include guidance about the importance of hand washing after the 

removal of gloves because contamination can occur even with glove use. Post 

additional signage about hand washing at all facilities.

2. Prohibit eating and drinking in the chart room and other areas where PPE is worn. 

3. Develop a written policy and educate employees and volunteers to remove PPE before 

entering the triage facility (other than the fish kitchen and garage area) as this could 

spread contamination from animals throughout the building. Other triage facilities 

should follow this same recommendation. 

4. Restrict the number of people involved in necropsies to the minimum number 

necessary to complete the procedure to limit potential exposure to zoonotic agents.

5. Remove the carpeting in the triage facility and replace it with nonporous flooring 

material that can be more easily cleaned.

6. Develop additional training for new and current employees and volunteers about 

the signs and symptoms of common zoonotic infections and steps they can take to 

minimize their risk of infection. Employees and volunteers with conditions such as 

pregnancy, valvular heart disease, or immunodeficiency that put them at risk for severe 

infection from certain zoonotic agents such as Q fever should share this information 

with their supervisor. 

7. Instruct employees and volunteers who develop signs and symptoms compatible with 

a zoonotic infection to inform their supervisor and seek medical care. They should tell 

their healthcare provider about their duties and exposure to marine mammals. 

8. Update the respiratory protection program following the OSHA Respiratory Protection 

Standard regulations [29 CFR 1910.134] to include employees and volunteers working 

in the necropsy area. Additionally, develop a policy for ensuring guest researchers are 

enrolled in their organization’s respiratory protection program and use appropriate 

PPE during aerosol-generating procedures (such as bone sawing during necropsy).

Personal Protective Equipment

Personal protective equipment is the least effective means for controlling hazardous 

exposures. Proper use of personal protective equipment requires a comprehensive program 

and a high level of employee involvement and commitment. The right personal protective 

equipment must be chosen for each hazard. Supporting programs such as training, changeout schedules, and medical assessment may be needed. Personal protective equipment 
Page 18 Health Hazard Evaluation Report 2011-0105-3173

should not be the sole method for controlling hazardous exposures. Rather, personal 

protective equipment should be used until effective engineering and administrative controls 

are in place.

1. Follow NAPSHV and CDC recommendations for PPE use during necropsy procedures 

[NASPHV 2010; CDC 2012a]. These include routinely wearing facial protection (face 

shield, or goggles and a surgical mask), fluid resistant (surgical) jumpsuit or shirt 

and pants that cover from neck to feet and arms, waterproof apron, and waterproof 

sleeves. Wear double gloves during necropsy. Wear N95 filtering facepiece (or higher) 

respirators during aerosol-generating procedures (such as during the use of bone saws 

or high pressure water hoses). For necropsies in which a risk assessment indicates 

a high likelihood for zoonotic agents in the cadaver and the necropsy cannot be 

conducted in a BSC, an N95 filtering facepiece (or higher) respirator should also be 

worn [CDC 2012a]. Offer alternatives, such as nitrile or vinyl, to powder-free natural 

rubber latex to reduce the risk of latex allergies. 

2. Wear rubber boots rather than street shoes when working around animal pens at the 

triage facility. 

3. Instruct maintenance staff to wear N95 filtering facepiece (or higher) respiratory 

protection during filtration room cleaning tasks.

4. Require laboratory staff to wear lab coats during all procedures in the laboratory. 

These coats should only be worn in the lab and laundered on-site or by a management 

provided laundry service.
Health Hazard Evaluation Report 2011-0105-3173 Page 19

Appendix A: Background Information on Zoonotic 

Infections

Q Fever 

Q fever is a zoonotic disease caused by the globally distributed bacterium Coxiella burnetii. 

There are two forms of disease, acute and chronic. Infected people develop clinical 

symptoms approximately half of the time. The most commonly recognized forms of acute 

disease are a nonspecific flulike illness, pneumonia, and hepatitis. Most people with acute 

Q fever infection recover completely, but a protracted fatigue syndrome has been reported 

in a minority of patients with acute infections. Chronic Q fever is rare and most commonly 

presents as endocarditis in those with pre-existing valvular heart disease. Pregnant women, 

immunosuppressed persons, and patients with pre-existing heart valve defects are at highest 

risk for chronic Q fever. 

Humans are typically exposed to the C. burnetii organism through contact with birth products 

(amniotic fluid and placenta), urine, or feces of infected animals. Ruminants (e.g., goats, 

sheep, and cattle) are considered the primary C. burnetii reservoir, but other species such as 

feral swine have been associated with human infections. C. burnetii is a highly infectious 

bacterium and exposure to only a few organisms can lead to infection. The organism can 

withstand a variety of environmental conditions. Transmission typically occurs via inhalation 

of contaminated aerosols or dust, but C. burnetii can rarely be transmitted by tick bites 

or ingestion of unpasteurized dairy products. Aerosols may be generated from infected 

animals, placental tissues and fluids, waste products, and contaminated straw or bedding [van 

Woerden et al. 2004].

Human exposure to marine mammals may be a potential risk factor for Q fever infection, 

but rates of infection among people working with marine mammals have not been 

previously investigated. C. burnetii infection in a marine mammal was first confirmed in 

the placental tissue of a rescued Pacific harbor seal in California [Lapointe et al. 1999]. 

Subsequent investigations have found evidence of C. burnetii infection in the Steller sea 

lion [Kersh et al. 2010], as well as in the Pacific harbor seal, harbor porpoise, and Northern 

fur seal [Lapointe et al. 1999; Duncan et al. 2012; Kersh et al. 2012]. A recent study did 

find C. burnetii seropositivity was detected in 34% of 215 Pacific harbor seals sampled in 

the Pacific Northwest [Kersh et al. 2012]. The significance of these new findings and the 

relationship to human Q fever infection is poorly understood. Recently, a patient with Q 

fever endocarditis was reported in Greenland with harbor or hooded seals implicated as a 

possible source of infection [Koch et al. 2010]. 

Brucellosis

Human brucellosis occurs worldwide and is most often associated with close contact with 

cattle, sheep, goats, and other hoofed mammals. The disease is caused by infection with 

bacterial species from the genus Brucella. The most commonly reported species infecting 

humans (and their typical reservoirs) include B. melitensis (sheep and goats), B. abortus 
Page 20 Health Hazard Evaluation Report 2011-0105-3173

(cattle), B. suis (swine), and B. canis (dogs). Humans are generally infected in one of 

three ways: eating or drinking something that is contaminated with Brucella spp. (e.g., 

unpasteurized milk or cheese), breathing in the organism (inhalation), or having the bacteria 

enter the body through skin wounds [CDC 2012b]. Inhalation of Brucella organisms is 

not a common route of infection, but it can be a significant hazard for people in certain 

occupations, such as those working in laboratories where the organism is cultured or in 

abattoirs [Trout et al. 1995].

Human brucellosis is rarely fatal, but symptoms can be severe. Acute symptoms may include 

nonspecific flulike illness, arthritis and, rarely, neurological disorders and endocarditis. 

Brucellosis can become a chronic condition in some patients, with symptoms such as 

depression, arthritis, or chronic fatigue syndrome. 

Brucella spp. infects a variety of marine mammals, including species of dolphin, porpoise, 

whale, seal, otter, and walrus [Ewalt et al. 1994; Ross et al. 1994]. To date, molecular 

analyses have linked marine mammal Brucella spp. to three naturally acquired, severe 

human illnesses [Sohn et al. 2003; McDonald et al. 2006] and one laboratory acquired illness 

[Brew et al. 1999]. Prevalence of Brucella spp. infections from marine mammal reservoirs is 

thought to be much higher than reports indicate, especially among those working with marine 

mammals [Hunt et al. 2008] and those in the fishing industry [Van Bressem et al. 2009] due 

to frequent misdiagnoses and underreporting. 

Leptospirosis

Leptospirosis is a potentially fatal bacterial disease caused by Leptospira spp. It may present 

as an acute, nonspecific flulike illness (e.g., fever, headache, muscle pain, diarrhea) or as a 

more severe chronic illness with symptoms such as liver or kidney failure, meningitis, or 

pulmonary hemorrhage. 

Leptospira spp. are spread through the urine of many wild and domestic animals (e.g., 

cattle, swine, rodents, dogs, sheep, and raccoons). Infection may result from direct 

contact with animal urine or from exposure to contaminated soil or water. Leptospirosis 

is also a recreational hazard (e.g., swimming, wading, paddling), an occupational hazard 

(e.g., slaughterhouse workers, veterinarians, farmers, sewer workers), and is associated 

with flooding. 

The most common exposure routes for development of leptospirosis include (1) drinking 

or contact with water (such as by swimming, rafting or kayaking) or soil that has been 

contaminated by urine or body fluids of infected animals or (2) exposure to the urine or 

body fluids of infected animals. The bacteria can enter the body through skin or mucous 

membranes (eyes, nose, or mouth), especially if the skin is broken from a cut or scratch 

[CDC 2012c]. 
Health Hazard Evaluation Report 2011-0105-3173 Page 21

Known marine mammal reservoirs of Leptospira spp. include fur seals [Smith et al. 1977], 

elephant seals [Colegrove et al. 2005], and harbor seals [Stamper et al. 1998]. Repeated 

outbreaks of leptospirosis have occurred in California sea lion populations from southern 

California to British Columbia. The outbreaks have killed large numbers of sea lions [LloydSmith et al. 2007]. These animals typically died after being stranded in regions with dense 

populations of other known Leptospira hosts (i.e., rodents, domestic animals, and other 

marine mammals), suggesting the potential for interspecies transmission, from marine 

mammals to humans directly or, possibly, through an intermediate species. Leptospira

excreted by sea lions has also been detected in sand [Cameron et al. 2008].
Page 22 Health Hazard Evaluation Report 2011-0105-3173

Appendix B: Informational Fact Sheets and 

Website Link Distributed to Employees and 

Volunteers

These informational fact sheets and websites were provided to facility employees and 

volunteers during the evaluation.

Facts about brucellosis: http://www.cdc.gov/brucellosis/

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

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







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

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

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

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

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















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









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 

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Health Hazard Evaluation Report 2011-0105-3173 Page 23

National Center for Emerging and Zoonotic Infectious Diseases

Division of High-Consequence Pathogens and Pathology

How do people get Leptospirosis?

There are two common ways to develop leptospirosis:

• Drinking or contact with water (such as by swimming, rafting 

or kayaking) or soil that has been contaminated by urine or 

body fluids of infected animals

• Exposure to the urine or body fluids of infected animals

What are the symptoms of leptospirosis?

Symptoms of leptospirosis can develop anywhere from 2 days 

to 4 weeks after being exposed to the bacteria. 

Common symptoms of leptospirosis include:

• Fever

• Chills

• Headache

• Muscle Aches

• Vomiting

• Diarrhea

• Abdominal Pain

• Jaundice (yellowing of the skin and eyes)

• Skin Rash

• Red Eyes

Which animals can spread leptospirosis to people?

Many animals can spread leptospirosis, including pets (such as 

dogs), farm animals, or wildlife. 

The animals that commonly develop or spread leptospirosis 

include:

• Rodents

• Raccoons

• Opossums

• Cattle

• Swine

• Dogs

• Horses

• Buffaloes

• Sheep

• Goats

CS219539-A

Leptospirosis

Leptospirosis is an infectious disease caused by bacteria. It can lead to 

potentially fatal infections of the kidney, liver, brain, lung or heart.

Am I at risk? 

There is always a risk of infection for people who have contact 

with infected animals or soil/water where the bacteria are present. 

People who work outdoors or with animals may be at increased 

risk for infection, such as:

• Farmers

• Mine Workers

• Sewer Workers

• Slaughterhouse Workers

• Veterinarians/Animal Caretakers

• Fishermen and people who work with fish

• Dairy Farmers

• Military Personnel

Those involved in outdoor 

freshwater activities may 

also face an increased risk. 

Activities may include:

• Swimming

• Rafting

• Kayaking

How is Leptospirosis treated?

If you have symptoms of leptospirosis, contact a doctor who 

can test for the disease. 

If an infection is confirmed, it will likely be treated with 

antibiotics (medicine that can cure the disease). Treatment is 

most effective when started as soon as possible.

How can Leptospirosis be prevented? 

There are several steps you can take to help prevent getting 

leptospirosis. These include:

• See a veterinarian to get vaccines for your pets that can 

protect against this disease

• Avoid contact with animal urine or body fluids, especially 

if there are any cuts or abrasion of the skin

• Do not swim in, walk in, or swallow water that may 

contain animal urine 

• Wear protective clothing or footwear near soil or water 

that may be contaminated with animal urine

For More Information Contact CDC Info:

1-800-CDC-INFO (1-800-262-4636)/TTY 1-888-232-6348 

or visit our website at www.cdc.gov/leptospirosis
Page 24 Health Hazard Evaluation Report 2011-0105-3173

Appendix C: Methods

Serologic Samples

NIOSH phlebotomists collected 10 milliliters of whole blood from each participant into 

a serum separation tube. The tubes were centrifuged and transported on ice by overnight 

courier to CDC in Atlanta, Georgia. For Q fever testing, the specimens were screened by an 

ELISA for IgG antibodies against phase II C. burnetii. If positive, or equivocal, they were 

tested by IFA assay to confirm the ELISA results and to determine IgG and IgM titers against 

phase I and phase II C. burnetii antigens. Coxiella testing was conducted the laboratory 

within CDC’s Rickettsial Zoonoses Branch. For brucellosis testing, sera were tested by 

the Brucella MAT, as previously described [Brown et al. 1981] with minor modifications 

including use of U-bottom plates, incubation at 28oC, and discontinued use of safranin. The 

Leptospira MAT [Dikken and Kmety 1978; Levett 2001] was used for leptospirosis testing 

of 20 serovars. Brucellosis and leptospirosis testing was conducted by the laboratory within 

CDC’s Bacterial Special Pathogens Branch.

Surface Samples

Solar-cult® cellulose sponges, premoistened with neutralizing buffer (Solar Biologics, 

Ogdensburg, New York) were used to collect samples on smooth, nonporous surfaces. 

Multiple surfaces in each area were wiped with a sponge to maximize potential recovery of 

C. burnetii from the environment. In a few cases, two sponge samples were combined into 

a composite sample because of the large size of the area. A new pair of disposable nitrile 

gloves was used for collection of each sample to prevent cross contamination of samples. 

Field blanks were collected at a rate of 10% of actual samples collected.

Vacuum samples were collected on 37-millimeter diameter, 0.3-micrometer pore size 

polytetrafluoroethylene filters with small nozzle attachments connected to battery-powered 

sampling pumps at 2 liters per minute. Porous surfaces, such as carpeted mats, were vacuumed 

over an area measured in cm2 using three sets of S-curve wipes over the surface. A new pair of 

disposable nitrile gloves was used for collection of each sample to prevent cross contamination 

of samples. Field blanks were collected at a rate of 10% of actual samples collected.

Bulk Samples

Approximately 10 to 50 grams of dirt or debris was collected and placed into sterile conical 

vials. A new pair of disposable nitrile gloves was used for collection of each sample to 

prevent cross contamination of samples. Field blanks were collected at a rate of 10% of 

actual samples collected. 

Air Samples

Personal breathing zone and area air samples were collected on 37-millimeter diameter, 

0.3-micrometer pore size polytetrafluoroethylene filters. The filter cassettes were connected 

to battery-powered SKC AirChek 2000 sampling pumps (SKC Incorporated, Eighty Four, 
Health Hazard Evaluation Report 2011-0105-3173 Page 25

Pennsylvania) and operated at 3 liters per minute. All pumps were precalibrated and 

postcalibrated with the sampling media connected. The collection and extraction efficiencies 

of this filter for another bacterial agent have been previously described by Burton et al. 

[2005, 2006]. Field blanks were collected at a rate of 10% of actual samples collected.

Sample Storage, Shipment, and Analysis

After collection, all samples were placed in plastic storage bags and stored and shipped 

at room temperature. Samples were shipped to the CDC Rickettsial Zoonoses Branch in 

Atlanta, Georgia, and analyzed for DNA extraction and quantitative PCR to determine 

if C. burnetii DNA was present. Methodology for this PCR assay has been previously 

described [Fitzpatrick et al. 2010]. The limit of detection for the PCR assay is 500 

organisms per 5 grams bulk environmental/sponge/37-mm filter sample. All DNA samples 

were analyzed by quantitative PCR targeting two C. burnetii genes. The IS1111 assay 

targets a variable number multi-copy gene segment and is therefore very sensitive. The 

com1 assay targets a single copy gene. For most strains of C. burnetii, the com1 assay is 

less sensitive than IS1111. However, some C. burnetii strains found in marine mammals 

have an altered IS1111 gene that is poorly amplified by this assay. Therefore, a stronger 

signal from the com1 PCR compared to the IS1111 PCR would be indicative of a marine 

mammal derived strain.
Page 26 Health Hazard Evaluation Report 2011-0105-3173

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Keywords: NAICS 813312 (Environment, Conservation and Wildlife Organizations), 

marine mammal, seal, sea lion, leptospirosis, brucellosis, Q fever, rehabilitation, rescue, 

Coxiella burnetii, Leptospira spp., Brucella spp., zoonotic infection, zoonoses.
Health Hazard Evaluation Report 2011-0105-3173 Page 31

The Health Hazard Evaluation Program investigates possible health hazards in the 

workplace under the authority of Section 20(a)(6) of the Occupational Safety and 

Health Act of 1970, 29 U.S.C. 669(a)(6). The Health Hazard Evaluation Program also 

provides, upon request, technical assistance to federal, state, and local agencies to control 

occupational health hazards and to prevent occupational illness and disease. Regulations 

guiding the Program can be found in Title 42, Code of Federal Regulations, Part 85; 

Requests for Health Hazard Evaluations (42 CFR 85).

Acknowledgments 

Analytical Support: Gilbert Kersh, Joshua Self, Kelly Fitzpatrick, and Robyn Stoddard, 

NCEZID

Desktop Publishers: Greg Hartle and Mary Winfree 

Editor: Ellen Galloway 

Health Communicator: Stefanie Brown 

Industrial Hygiene Field Assistance: Joshua Self, NCEZID

Logistics: Donald Booher and Karl Feldmann

Medical Field Assistance: Barbara MacKenzie and Debbie Sammons; Ruchika Saini, 

formally with the University of Kentucky College of Medicine; Adam Bjork, CGH

Medical Protocol Development: Alicia Anderson, NCEZID; Adam Bjork, CGH

Availability of Report

Copies of this report have been sent to the employer, employees, and union at the 

facility. The state and local health department and the Occupational Safety and Health 

Administration Regional Office have also received a copy. This report is not copyrighted 

and may be freely reproduced. 

This report is available at http://www.cdc.gov/niosh/hhe/reports/pdfs/2011-0105-3173.pdf

Recommended citation for this report:

NIOSH [2013]. Health hazard evaluation report: evaluation of zoonotic 

disease and exposures in persons working with marine mammals. By 

Gibbins J, Niemeier RT, de Perio MA, Mueller C. Cincinnati, OH: U.S. 

Department of Health and Human Services, Centers for Disease Control 

and Prevention, National Institute for Occupational Safety and Health, 

NIOSH HETA No. 2011-0105-3173.
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