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March 16, 2001

Foot & Mouth Disease:
Could it happen here?

By Lana Robinson
Field Editor

Foot & Mouth Disease (FMD) outbreaks around the world in the last 13 months, and most recently in Great Britain and Europe, along with episodes of BSE (bovine spongiform encephalopathy), have brought animal health issues to the forefront of Texas livestock producers' concerns.

"Naturally, BSE is of concern because of human health implications, but we feel like with our production practices, its occurrence in this country is very unlikely. FMD, however, is highly infectious and the potential for its arrival here is high, perhaps an airline flight away," said Jon Johnson, a Texas Farm Bureau Commodity and Regulatory Activity associate director. "Needless to say, FMD could be devastating to the livestock and wildlife industries of Texas and the U.S. This is a real serious threat."

The disease is currently affecting four of the world's seven continents: Asia, Africa, South America and Europe, leaving only North America, Australia and Antarctica free of the disease.

Foot-and-mouth disease (FMD) is a severe, highly communicable viral disease of cattle and swine. It also affects sheep, goats, deer, and other clovenhooved ruminants. According to USDA-APHIS Veterinary Services, this country has been free of FMD since 1929, when the last of nine U.S. outbreaks was eradicated.

The disease is characterized by fever and blisterlike lesions followed by erosions on the tongue and lips, in the mouth, on the teats, and between the hooves. Many affected animals recover, but the disease leaves them debilitated. It causes severe losses in the production of meat and milk.

The disease, which spreads widely and rapidly, is caused by a virus. The virus can persist in contaminated fodder and the environment for up to one month, depending on the temperature and pH conditions. There are at least seven separate types and many subtypes of the FMD virus. Immunity to one type does not protect an animal against other types.

"Vaccines for prevention of FMD are not fool-proof, so they are primarily used only to contain FMD in a specific area. Because vaccinated animals will test positive, they cannot be shipped internationally and protocols require the animals to be destroyed as soon as the disease is eradicated," said Johnson.

Cattle, pigs, sheep, goats and deer are highly susceptible, and can exhibit clinical disease signs after an incubation period of only three to eight days. To stop the spread of infection, affected or exposed animals must be slaughtered, then burned or buried. Premises and equipment must be disinfected to prevent disease spread.

FMD virus easily spread

According to the Texas Animal Health Commission, the state's livestock health regulatory agency, worldwide, nearly two-thirds of the FMD outbreaks are attributed to the introduction and feeding of contaminated meat, meat products or garbage to animals. About a quarter of infection is spread by airborne transmission, and about 10 percent is comprised of infected livestock importations or contaminated objects and people.

"Foot and mouth virus poses special challenges, requiring proper disinfection and biosecurity protocols. People who have worked around or been near infected animals can inadvertently carry and spread the virus
via their equipment, cars, clothing, shoes, or even for a short time in their lungs or pharynx (throat)," said Dr. Linda Logan, Texas' state veterinarian and TAHC head.

She pointed out that studies indicate the virus can drift up to 40 miles on the wind, another hurdle to confining an FMD outbreak to a defined geographic area.

"I am particularly concerned when cases of FMD occur close to a highly populated area—or near a major international airport," said Dr. Max Coats, who heads up the TAHC's animal health programs and field operations. "Because of the virus' ability to ride the wind, it's possible that ranching or farming equipment being exported by affected countries could be contaminated. It may sound far-fetched, but with a disease of this impact, we're always concerned about potential scenarios. Within 24 hours, an animal, animal product, person or piece of equipment can be transported nearly anywhere in the world. There's always a chance that a virus, pest or dangerous bacteria will be hitching the ride, too."

Dr. Coats added that there is an additional risk that contaminated items could be smuggled or inadvertently brought into the country by the millions of visitors and returning U.S. citizens who travel internationally.

"Around 4.5 million British residents, for example, came to the U.S. on direct flights in l999," he noted.

FMD can mimic other diseases

FMD can be confused with several similar, but less harmful, diseases, such as vesicular stomatitis, bluetongue, bovine viral diarrhea, and foot rot in cattle, vesicular exanthema of swine, and swine vesicular disease. Whenever mouth or feet blisters or other typical signs are observed and reported, laboratory tests must be completed to determine whether the disease causing them is FMD.

While the disease is widespread around the world, North America, Central America, Australia, New Zealand, Chile, and some countries in Europe are considered free of FMD. Various types of FMD virus have been identified in Africa, South America, Asia, and part of Europe.

FMD is one of the most difficult animal infections to control. Because the disease occurs in many parts of the world, there is always a chance of its accidental introduction into the United States.

Animals and animal byproducts from areas known to be infected are prohibited entry into this country.

FMD economically devastating

Livestock animals in this country are highly susceptible to FMD viruses. If an outbreak occurred in the United States, this disease could spread rapidly to all sections of the country by routine livestock movements unless it was detected early and eradicated immediately. If FMD were to spread unchecked, the economic impact could reach billions of dollars in the first year. Deer and wildlife populations could become infected rapidly and could be a source for reinfection of livestock. Logan said FMD is probably the most economically damaging livestock disease.

In addition to the loss of thousands of animals, estimated losses to British farmers from the week-long ban on the transport and marketing of livestock susceptible to the disease were pegged at $73 million.

"Consider the damage to our economy, if we were to have the disease introduced into the U.S. and exports of live animals and meat were prohibited. Last year, the U.S. shipped out more than $4.2 billion worth of these commodities. Texas ranked third among all states, shipping out more than $736 million in animals and meat products," she said.

Logan cited South Korea as an example of how quickly it can hit. Free of FMD since l934, South Korea was struck by the virus in late March 2000 and lost $400 million worth of pork exports to Japan and its other trading partners because of it.

Safeguards under review

A specialist in tick-borne and foreign animal diseases, Logan said, "A global economy brings with it global risks, and we must be prepared for the inevitable threats posed by international trade and travel."

The TAHC veterinarian also serves on a national team reviewing how best to safeguard U.S. livestock from foreign diseases and pests. USDA-APHIS Veterinary Services tapped the National Association of State Departments of Agriculture (NASDA) to conduct the review. NASDA's review panel and committee chairs are comprised of individuals, like Logan, who represent industry, academia and the states whose expertise and knowledge is deep. The review will look at ways to improve, where needed, the overall safeguarding system covering four main areas:

1) Exclusion Activities—those things designed to prevent the introduction of invasive species, pests and diseases from entering the country;

2) International Information—collection and analysis of data is needed for timely decision making on risk analysis, create regulations, identify threats and facilitate trade;

3) Domestic Surveillance and Detection—those activities that monitor for diseases/pests affecting the U.S. animal population. Detection includes activities to identify diseases/pests not known to occur in this country or in particular regions of the U.S. and other animal health events; and

4) Response—actions needed to prepare for and address adverse animal health events.

The value of animal industries in the U.S. is more than $100 billion, and the value of animal exports is more than $11 billion, making the safeguarding role a crucial one.

The state veterinarian urged livestock producers in Texas to step up their surveillance and to take precautions to protect herds from possible contamination.

"If you've traveled internationally, don't risk carrying disease home to your herd. Disinfect your boots before working with your livestock. Producers who feed waste food to swine should be particularly careful to ensure that all scraps are well cooked," she said.

She also suggested that producers limit vehicle traffic and visitors onto their premise, and keep new animals isolated for several days prior to adding them to the existing herd.

"If your livestock become lame or develop blisters or sores, call us at 1-800-550-8242. Our emergency response within the first 24 hours after the first signs of disease will affect our outcome over the next six months," Logan said.

The TAHC and U.S. Dept. of Agriculture's Veterinary Services in Texas operate the toll-free number 24 hours a day for emergency calls.