APHIS Factsheet

Veterinary Services July 2013

High-Consequence 

Foreign Animal 

Diseases and Pests 

In carrying out our safeguarding mission, the U.S. 

Department of Agriculture’s (USDA) Animal and Plant 

Health Inspection Service (APHIS) works to ensure the 

continued health and welfare of our Nation’s livestock 

and poultry populations. One important aspect of this 

work is emergency preparedness—making sure we are 

ready to respond effectively when faced with a foreign 

animal disease outbreak or pest infestation. As part 

of these efforts, APHIS’ animal health officials identify 

“high-consequence” foreign animal diseases and pests. 

These are serious diseases and pests that do not 

currently exist in the United States. If introduced here, 

they pose a severe threat to U.S. animal health and, in 

some cases, the economy and human health as well. 

The list divides diseases and pests into tiers according 

to risk level, as described below.

Tier 1

Tier 1 diseases are those of national concern. They 

pose the most significant threat to animal agriculture in 

the United States, as they have the highest risks and 

consequences. This category includes:

•	 African swine fever*

•	 classical swine fever*

•	 foot-and-mouth disease*

•	 avian influenza (any strain that is highly 

pathogenic or has zoonotic significance)*

•	 virulent Newcastle disease*

Tier 2

Tier 2 diseases are transmitted primarily by pests. How 

quickly these diseases spread and APHIS’ ability to 

control or eradicate an outbreak depends largely on 

whether these pests are present in the environment 

and whether they can transmit the disease between 

animals. This category includes:

•	 heartwater

•	 New World screwworm

•	 Rift Valley fever*

•	 Venezuelan equine encephalitis*

Tier 3

Tier 3 diseases and pests pose less risk and fewer 

consequences than those in Tiers 1 and 2, but still 

rise to the level of inclusion because of their potential 

negative impact on animal or human health. This 

category includes:

•	 African horse sickness

•	 contagious bovine pleuropneumonia and 

contagious caprine pleuropneumonia

•	 glanders and melioidiosis

•	 henipaviruses (Hendra and Nipah)*

•	 rinderpest* and peste des petits ruminants*

•	 tropical bont tick

What the List Means

These high-consequence foreign animal diseases and 

pests are of primary importance to APHIS’ emergency 

preparedness officials, guiding many of our program 

priorities. For example, the list will help inform decisions 

on how we procure countermeasures to address a 

disease outbreak and, potentially, funding for research 

and response activities. The diseases marked with an 

asterisk are those APHIS has identified as biological 

threats that need to be considered in program priorities 

and countermeasure stockpile requirements.

How We Developed the List 

APHIS developed this list after carefully considering all 

foreign animal diseases and pests that could negatively 

affect livestock or poultry. We also took into account 

disease agents that are identified in the agricultural 

select agent program, as well as those that can severely 

threaten public health or animal health (zoonotic 

diseases) or the safety of animal products. We did 

not include diseases and pests that are endemic, or 

common, in the United States or any disease APHIS 
already manages through one of our animal health 

programs (e.g., brucellosis, bovine tuberculosis, 

scrapie, etc.).

When developing the list, another overall issue we 

considered was a disease’s potential for introduction 

into the United States. The eight criteria below also 

helped guide our decisions on whether or not to 

designate an animal disease or pest as one of high, 

negative consequence. 

1) high epidemic/epizootic potential, or the 

ability to rapidly spread and infect a large 

number of animals

2) high economic impact

3) large impact on trade, both domestic and 

international

4) high animal morbidity and mortality, or 

the capability to cause disease and death 

respectively

5) high potential to infect multiple species

6) inability to detect the disease rapidly

7) ability to vaccinate for the disease 

8) high zoonotic (can be transmitted from animals 

to people) potential 

APHIS animal health officials will review and update this 

list periodically. In doing so, we will seek broad input 

from stakeholders to inform our decisions.

Learn More

If you have any questions about the list of high-consequence 

animal diseases and pests, please call APHIS Veterinary 

Services at (301) 851-3595. To learn more about animal 

health emergency management, go to www.aphis.usda.

gov/animal_health/emergency_management.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture

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