Response 

Strategies

APHIS Foreign Animal 

Disease Framework

FAD PReP Manual 2-0

1
Document Overview

• Preparedness and response planning for foreign animal 

disease (FAD) incidents is crucial to protect animal health, 

public health, the environment, and to stabilize animal 

agriculture, the food supply, and the economy. 

• The FAD Framework: Response Strategies (FAD PReP Manual 

2-0) describes response goals, FAD response strategies and 

principles, and zone and premises designations.

2
Foreign and Emerging Animal Diseases

• An FAD is defined as a transboundary animal disease or 

pest not known to exist in the U.S. animal population. 

• An emerging animal disease may include any terrestrial 

animal, aquatic animal, or zoonotic disease not yet 

known or characterized, or any known or characterized 

terrestrial or aquatic animal disease in the United States 

or its territories, that changes or mutates in 

pathogenicity, communicability, or zoonotic potential to 

become a threat to animals or humans.

– APHIS VS developed a framework for responding to emerging animal 

diseases, “Veterinary Services Proposed Framework for Response to 

Emerging Animal Disease in the United States,” available at 

https://www.aphis.usda.gov/animal_health/downloads/vs_emerging_di

seases_framework.pdf 3
FAD Response Goals

• In the event of an FAD outbreak, three key 

response goals are to:

1) Detect, control, and contain the FAD in animals as 

quickly as possible;

2) Eradicate the FAD using strategies that seek to 

stabilize animal agriculture, the food supply, and the 

economy, and to protect public health and the 

environment.

3) Provide science- and risk-based approaches and 

systems to facilitate continuity of business for noninfected animals and non-contaminated animal 

products.

4
FAD Response Goals

• Achieving the FAD response goals will allow: 

– individual livestock facilities, States, Tribes, 

regions, and industries, to resume normal 

production as quickly as possible.

– the United States to regain disease-free status 

without the response effort causing more 

disruption and damage that the disease outbreak 

itself.

5
Epidemiological Principles of Response

Three key epidemiological principles form the 

foundation of any FAD response:

1. Prevent contact between the disease and 

susceptible animals.

2. Stop the production of the FAD agent in infected 

or exposed animals.

3. Increase the disease resistance of susceptible 

animals to the disease, or reduce the shedding 

of the FAD agent in infected or exposed animals.

6
Regulatory Intervention During an FAD Outbreak

• An FAD outbreak in the United States may result in 

emergency regulatory intervention by States, Tribal 

Nations, and/or Federal authorities. 

• The USDA and the affected States and Tribes will 

work together in a Unified Command, per the 

National Incident Management System, to detect, 

control, and contain the disease as expeditiously as 

possible. 

7
Regulatory Intervention During an FAD Outbreak

The scope of regulatory intervention and the selection of a 

response strategy or strategies in an FAD outbreak will depend on 

the following:

• Transmission characteristics of the FAD agent

– Rate of contagious disease agent transmission

– Potential for zoonotic transmission

– Number and types of susceptible animal species.

• Consequences of the FAD outbreak

– To national security, food security, public health, animal health, the 

environment, and the economy

– Regulatory impacts for owners, growers, stakeholders, and the general 

public. 

8
Regulatory Intervention During an FAD Outbreak

(continued)

• Acceptance

– Social and political acceptance of the response policy by different 

communities.

• Local, State, Tribal, U.S. regional, U.S. national, North American, and 

international.

• Scale of the outbreak

– Number of animals, species, and premises infected 

– The susceptible animal population density for infected or high-risk areas.

• Rate of outbreak spread

– Numbers and types of premises

– Numbers and types of animals

– Rate at which each Infected Premises (IP) leads to infection of one or more 

additional IP. 

• Veterinary countermeasures available

– Availability and efficacy of countermeasures, such as FAD vaccines.

9
Regulatory Intervention During an FAD Outbreak 

(continued)

• Resources available to implement response strategies

– Capabilities and resources available to:

• eradicate an FAD in domestic animals and 

• to control and eradicate and FAD in potential wildlife reservoirs.

• Domestic animal disease management capabilities

– Capability, feasibility, and resources available to: 

• eradicate an FAD in domestic animals as an emergency response 

control as an animal disease program 

• monitor as an endemic animal disease. 

• Wildlife management capabilities

– Capability, feasibility, and resources available to eradicate, control, or 

monitor an FAD in wildlife reservoirs. 

10
Examples of State-Federal-Tribal Emergency 

Interventions during an FAD Outbreak

Emergency eradication effort

Twelve months or less, 

regulatory intervention at time 

of outbreak by State-FederalTribal authorities.

Extended emergency 

eradication effort

Greater than twelve months, 

regulatory intervention at time 

of outbreak by State- FederalTribal authorities.

Individual State or Tribal 

Nation animal disease control 

program

Short-term or long-term, with 

State or Tribal Nation 

requirements.

Animal disease monitored 

with limited or no regulatory 

intervention

Short-term or long-term, with 

little or no regulatory 

intervention by State-FederalTribal authorities.

National animal disease 

control program

Long-term regulatory control 

program conducted by StateFederal-Tribal authorities.

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Transmission Characteristics of FAD Agents

• An animal disease is either:

– contagious, meaning it is transmitted through animal-animal 

contact or fomite-animal contact, or 

– not contagious, meaning it is transmitted by another means 

(for example, an arthropod vector). 

• Contagious diseases can be classified as: 

– Highly contagious.

• Require a rapid and coordinated response to control and eliminate the agent.

– Not highly contagious. 

• May require a response for reasons other than the rapid spread of the agent, 

including disruptions to interstate commerce, international trade, or zoonotic 

potential.

– Classification depends on how rapidly the disease agent can 

move from animal to animal and farm to farm. 

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Terrestrial FAD Threats

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FAD

Primary type 

of animal affected

Highly 

contagious

disease 

Vectorborne

disease

Zoonotic

disease

potential

Diseases with FAD PReP Response Plans (Red Books)

Highly pathogenic avian influenza (HPAI) Avian, others Yes No Yes

Foot-and-mouth disease (FMD) All cloven hoofed animals Yes No No

Classical swine fever (CSF Swine Yes No No

Newcastle disease (ND)

(virulent ND virus) 

Avian Yes No Yes 

Minor

Diseases with FAD PReP Disease Response Strategies

African swine fever Swine Yes Yes No

Japanese encephalitis Equine, swine No Yes Yes

Peste des petits ruminants Caprine, ovine Yes No No

Rift Valley fever Bovine, ovine, caprine No Yes Yes

Diseases with VS Response Materials 

Contagious equine metritis Equine No No No

Equine piroplasmosis Equine No Yes No

Schmallenberg virus Bovine, caprine, ovine No Yes No

Vesicular stomatitis virus Equine, bovine, swine, ovine, 

caprine

No Yes Yes

Rare
Terrestrial FAD Threats (continued)

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FAD

Primary type 

of animal affected

Highly 

contagious

disease 

Vectorborne

disease

Zoonotic

disease

potential

Other FAD Threats (Alphabetical Order)

African horse sickness (AHS) Equine No Yes No

Akabane Bovine, ovine, caprine No Yes No

Bovine babesiosis Bovine No Yes No

Contagious bovine pleuropneumonia Bovine Yes No No

Contagious caprine pleuropneumonia Caprine Yes No No

Dourine Equine No No No

Glanders Equine Yes No Yes

Heartwater (Ehrlichia ruminantium) Bovine, ovine, caprine, other 

ruminants

No Yes No

Lumpy skin disease Bovine No Yes No

Nairobi sheep disease Ovine, caprine No Yes Yes

Minor

Nipah, Hendra

(Henipavirus)

Swine, equine respectively Yes

(Nipah)

No Yes

Rabbit hemorrhagic disease Wild and domestic rabbits (sp. 

Oryctolagus cuniculus)

Yes No No

Sheep pox, goat pox Ovine, caprine Yes No No

Surra (Trypanosoma evansi) Equine, bovine, others No Yes No

Swine vesicular disease Swine Yes No No

Theileriosis (East Coast fever) Bovine No Yes No

Venezuelan equine encephalitis Equine, avian No Yes Yes
FAD Pest Threats

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Foreign pest

common name

Foreign pest

scientific name

Primary type of 

animal affected

Disease transmitted;

condition caused

Zoonotic disease

potential

Foreign Animal Pest Threats with FAD PReP Disease Response Strategies

Screwworm—New 

World

Cochliomyia hominivorax Warm-blooded animals Myiasis Myiasis

VS Control Program Exists

Cattle fever tick Rhipicephalus annulatus

(formerly Boophilus annulatus)

Bovine, ovine, caprine, other 

species

Bovine babesiosis No

Southern cattle tick Rhipicephalus microplus

(formerly Boophilus microplus)

Bovine, ovine, caprine, other 

species 

Bovine babesiosis No

Other Foreign Animal Pest Threats (Alphabetical Order by Pest Scientific Name)

Bont tick Amblyomma hebraeum Bovine, reptiles, other 

species

Heartwater African tick-bite fever

Tick typhus

Tropical bont tick Amblyomma variegatum Bovine, reptiles, other 

species

Heartwater

Bovine 

dermatophilosis

Nairobi sheep disease 

African tick-bite fever

Tick typhus

Crimean-Congo hemorrhagic fever 

(CCHF)

Yellow fever

Screwworm— Old 

World

Chrysomya bezziana Warm-blooded animals Myiasis Myiasis

Louse fly Hippobosca longipennis Canine, livestock, other 

species

Bite only Bite only

European castor 

bean tick

Ixodes ricinus Bovine, ovine, caprine, other 

species

Bovine babesiosis CCHF

Lyme disease

Bovine babesiosis (splenectomized

population)

Licking fly Musca vitripennis Bovine Bovine filariosis No

Sheep scab, sheep 

mange

Psoroptes ovis Bovine, ovine, other species Mange No

Brown ear tick Rhipicephalus appendiculatus Bovine, ovine, caprine, other 

species

East Coast fever 

Nairobi sheep disease

Tick typhus

Note: Myiasis = fly larvae feeding on the host living tissue; mange = hair loss, itching, and inflammation from mite infestation; African tick-bite fever = Rickettsia africae (human disease); 

tick typhus = Rickettsia conorii (human disease).
Example Response Strategies

• The response strategy used for the control and eradication of an 

FAD in domestic livestock or poultry depends on

– the disease agent,

– zoonotic potential,

– ability to control the agent,

– economic impact, and

– availability of emergency vaccines.

• There are five strategies for controlling and 

eradicating a highly contagious FAD in domestic 

livestock or poultry.

– These strategies are not mutually exclusive.

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The Five Response Strategies

1. Stamping-Out

– Depopulation of clinically affected and in-contact susceptible animals.

2. Stamping-Out Modified with Emergency Vaccination to Kill 

– Depopulation of clinically affected and in-contact susceptible animals.

– Vaccination of at-risk animals, with subsequent depopulation and disposal 

of vaccinated animals. 

– Depopulation and disposal can be delayed until logistically feasible.

3. Stamping-Out Modified with Emergency Vaccination to 

Slaughter 

– Depopulation of clinically affected and in-contact susceptible animals and 

vaccination of at-risk animals.

– Slaughter and processing of vaccinated animals, if animals are eligible for 

slaughter under: 

• USDA Food Safety and Inspection Service (FSIS) authority and rules

• State and Tribal authority and rules. 

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The Five Response Strategies (continued)

4. Stamping-Out Modified with Emergency Vaccination to Live

– Depopulation of clinically affected and in-contact susceptible animals 

and vaccination of at-risk animals. 

• No subsequent depopulation of vaccinated animals. 

• Vaccinated animals intended for breeding, slaughter, or other 

purposes live out their useful lives.

5. Emergency Vaccination to Live without Stamping-Out 

– Vaccination used without depopulation of infected animals or 

subsequent depopulation or slaughter of vaccinated animals. 

6. Manage Outbreak Without Widespread Stamping-Out or 

Vaccination

– In some cases, as when the disease agent is already

 widespread prior to detection or when it involves a 

 large number of animals, and when no vaccine in 

 readily available.

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FAD Investigations

• The objectives of FAD and emerging disease investigations are to

– provide a veterinary medical assessment, 

– provide presumptive and definitive diagnostic testing results, and 

– ensure that the appropriate veterinary medical countermeasures, 

regulatory actions, and communications are recommended and 

implemented. 

• Investigations provide confirmative diagnostic testing results as 

rapidly as possible. 

– Once an FAD agent is detected, incident 

management will be tailored to the specific 

disease agent and circumstances of the outbreak. 

• The APHIS policies and procedures for FAD 

investigations are defined in the: 

– FAD Investigation Manual (FAD PReP Manual 4-0) 

– Veterinary Services Guidance Document 12001.

19
FAD Investigations

FAD Investigations from 1997 to 2014

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Designating Zones, Areas, and Premises

Zones

• Infected Zone 

• Buffer Zone 

• Control Area

• Surveillance Zone

• Free Area

• Containment Vaccination Zone

• Protection Vaccination Zone 

Premises

• Infected Premises

• Contact Premises

• Suspect Premises

• At-Risk Premises

• Monitored Premises

• Free Premises

• Vaccinated Premises

Establishment of zones and premises is essential for FAD response 

efforts. In general, a response involves 7 types of zones/areas and 7 

types of premises.

21
Example Zones, Areas, and Premises

Note: Figures are not to scale. The Vaccination Zone can be either a Protection Vaccination Zone or Containment Vaccination Zone.

22
Recognition of Disease-Free Status

• The World Organization for Animal Health (OIE) recognizes official 

disease statuses for member countries for 

– foot-and-mouth disease (FMD),

– rinderpest, 1

– contagious bovine pleuropneumonia (CBPP),

– bovine spongiform encephalopathy (BSE),2

– African horse sickness (AHS),

– classical swine fever (CSF), and

– peste de petits ruminants (PPR).

• Through an agreement between the World Trade Organization, 

the OIE is responsible for recognizing disease-free areas, pestfree areas, and/or risk status for trade purposes.

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1 Rinderpest is no longer listed due to its worldwide eradication, officially declared in May 2011 by the 

OIE.

2 OIE recognizes freedom of all diseases listed here except for BSE, which it recognizes as “negligible” or 

“controlled” risk status
Recognition of Disease-Free Status

• OIE categories for official country recognition for FMD 

virus are:

– FMD-free country where vaccination is not practiced

– FMD-free country where vaccination is practiced

– FMD-free zone where vaccination is not practiced

– FMD-free zone where vaccination is practiced

– FMD-free compartment

– FMD-infected country 

or zone.

WAHID, 2014

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Recognition of Disease-Free Status

• Any member that wishes to be included in the list of 

designated disease-status countries or to change its 

statues sends a request to the OIE Scientific and 

Technical Department.

– The request should include specific documentation and 

relevant questionnaires for the disease. 

• The Director General submits the request to the 

Scientific Commission for evaluation.

• For diseases other than FMD, CBPP, BSE, AHS, CSF, and 

PPR, Member countries can self-declare their entire 

country, zone, or compartment disease-free.

– They must provide relevant epidemiological evidence that 

requirements for disease status have been met in 

accordance with OIE standards.

25
Executing a Response Strategy

• Some of the critical activities and tools that are 

employed to execute response strategies during 

an FAD outbreak, including:

– Epidemiological investigation and tracing

– Biosecurity

– Surveillance

– Diagnostics

– Quarantine and movement control

– Continuity of business

– Cleaning and disinfection

– Disposal

– Public awareness campaigns. 

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Find Us Online

• For more information, please visit the APHIS FAD 

PReP website at

https://www.aphis.usda.gov/fadprep. 

• Questions? Comments? 

FAD.PReP.Comments@aphis.usda.gov

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