Foot-and-Mouth Disease Attack on the Midwest U. S.

Purpose To develop and evaluate a plausible scenario for an attack on the Midwest United States using Foot-and-Mouth disease virus. The scenario is designed to facilitate discussions on broad agricultural preparedness and response issues To develop and evaluate a plausible scenario

Foot-and-Mouth Disease Foot-and-mouth disease (FMD) is an extremely contagious, viral disease of domestic cloven-hoofed and many wild animals, characterized by fever, vesicular lesions and, subsequent erosions of the epithelium of the mouth, tongue, nares, muzzle, feet, and teats. Definition: If have one infected or exposed animal in a herd, can expect all animals in herd to develop disease within few days. Extremely contagious – the most contagious disease we know –moves like wildfire through herd. Viral – caused by a virus Cloven hoof – two toed domestic animals – cattle, sheep, goats, pigs. Wildlife – affects two-toed animals bison, deer, antelope. Some other wild animals such as elephants could be affected by some of the strains in Asia.

Availability of FMD Virus FMD Virus is easily obtained in many countries of the world Distribution and Recent Activity Present Recent Activity Free 1999 2000 2001 (Rev. 3 - 27 01)

FMD Virus Stability pH Sensitive: <6.5 or >11.0 UV Sensitive: (sun light) Survives in moist, organic-rich materials It is important to understand virus stability to understand what happens to contamination on the farm and beyond. Virus very sensitive to pH – either low pH or high –below 6.5 or higher than 11. Disinfectants that have a low pH such as ordinary vinegar or acetic acid can inactivate virus. Alkaline solutions also good. Approved list is available. Sunlight can inactivate virus quickly. If have bedding or feed that has been contaminated and circumstances are cool and moist such as inside a barn in winter, virus can last a long time even weeks or months. Depends on weather and conditions.

FMD Transmission Aerosols Direct contact Meat products Fomites 1. Aerosols. Transmission for the most part is by aerosols. Infection is in lungs, when animals exhale it is sent airborne in large amounts, especially with pigs. Estimated that for each liter of air that a pig exhales, there is enough virus to infect 10,000 pigs. Farm with a lot of pigs – form a cloud of virus – cloud can move with the wind. When have low temperature, high humidity and lack of sunlight virus can move from farm to farm. Direct contact of animal-to-animal. Meat Products. Virus is in all organs of body. Does not survive in meat because change in pH is in muscle, but it will survive in bone marrow and internal organs. Risky – sausage where organs are included with meat. If sausage is contaminated and leftovers are fed to pigs, pigs can get FMD. Fomites. Inanimate objects such as barn, cars, boots which can carry virus farm to farm. Biosecurity/animal health precautions needed.

FMD - Epidemiology Morbidity: >95% Mortality: Adults <1% Neonates >50% Carrier state: in cattle (6-24 months) Morbidity Close to 100% of animals on a farm will be affected. Mortality Less than 1% of animals will die, but they will be less productive than they were. Doubtful that dairy cows will produce milk. Economic losses for producers are tremendous. In young animals between 50 to 100% will die. Calves 50%; lambs 60-70%; piglets 100%. Carrier State If recover, carry virus in throat for up to two years. Even if vaccinated, could carry virus. Vaccination prevents clinical manifestation, but still could carry. If, for example, we would vaccinate, would have to mark cattle so they are not in national herd, otherwise have potential to circulate virus.

FMD- Cattle Tongue Lesions Tongue in cattle most dramatic for lesions. Bumps form first, then blisters. Blisters fuse together – oval and white. When this whole blister breaks –a sheet of epithelium falls off, and leaves raw bleeding tongue that is extremely painful, and animal cannot eat. To help animal, water/feed are placed under its head.

FMD – Swine Feet & Snout Lesions Pigs are “factory” of the virus. Exhale a lot of virus. Pigs have visible lesions. Foot lesions so painful that pigs walk on knuckles and squeal. Blisters on snout.

APHIS Response Goal: To detect, control and eradicate the disease agent as quickly as possible to return the United States to free status The scope of the disaster will vary by the speed of the response Multiple foci Real time exponential growth

Risk Factors for Spread of FMD Animal density Animal concentration points Livestock movements Livestock markets Sale Barns Fairs and shows People movements Wildlife Climate

Population at Risk

Model Assumptions Limited to one location 11 days from exposure to detection For 60 day period Limited livestock movement No climatic factors No wildlife spread No people spread

Introduction of FMD Single foreign operative introduces FMD virus into a single cattle herd in the United States Midwest

Day 1 Total = 13 Farms Affected

Quarantined States

National Activities Movement controls (temporary) animals in transit continue to destination, no further movements allowed Intensive surveillance National and international communications

Zones of Control Infected zone Surveillance zone Quarantined area around the infected or presumed infected premises, (10km – 6mi as starting point) May be alter based on weather, terrain, wildlife, livestock concentrations, etc Surveillance zone Restricted area around the infected zone May initially include the entire affected state and those in close proximity to infected zone Will be modified pending tracing and surveillance results

Infected Zone Activities Intensive epidemiological investigations of farmed animals and wildlife Perimeter movement controls of roads Animals or animal products stopped Conveyances and people decontaminated Depopulation and decontamination of infected farms

Surveillance Zone Activities Case finding Livestock concentration points Sick calls Awareness campaign Tracing contacts with infected animals and premises We presume 8 contacts per farm per week Livestock, vehicles, people and materials Vaccination of a buffer zone around infected farms if efficacious

Appraisal – Depopulation - Disposal Appraise affected animals and dispose of them as close to the affected premises as possible – within 12-24 hours of culling Estimated requirements are 5 workers per herd of 40 animals per day for depopulation and disposal Average herd size = 200 animals

Decontamination of Premises Thorough cleaning and disinfecting of facilities, products and equipment 3 people per farm per day for each 40 animals in herd

Day 5 All Total = 64 Affected Farms

Day 25 Total = 3091 Affected Farms

Day 60 Total = 5844 Affected Farms

Analysis Scenario suggested a single operative infecting a single farm but multiple farms would be more likely and could effectively spread FMD nationwide Computer model showed that with the single introduction there would be 5844 affected farms within 60 days

Analysis 200 animals on each farm $350 to appraise each farm $5.50 euthanasia for each animal $325 indemnity for each animal $15 to dispose of each animal $8,000 to clean and disinfect each farm $3,200 further surveillance cost from each affected premises

Analysis Appraise $ 2.04M Euthanasia $ 6.43M Indemnity $379.86M Disposal $ 17.53M Clean/Disinfect $ 46.75M Surveillance $ 18.71M Total for ONE incident $471.32M

Analysis Export Losses with our markets closed Live Animals Germplasm Animal Feed Human Food Animal Byproducts $Millions?? $Billions??