FOOT AND MOUTH DISEASE (FMV)

By Dr. Herbert N. Prince

FMV is a small naked RNA virus in the picornavirus family which includes its first and second cousins polio, ECHO, Coxsackie A and B, encephalomyocarditis virus and hepatitis A, all human pathogens. FMV is not. FMV, restricted to animals of cloven hoof (cows, goats, pigs), is the only virion of this group that is a mucocutaneous pathogen not infecting nervous, muscle, intestinal or hepatic tissue, as the above. It is not lethal to infected farm animals but is debilitating, highly contagious rendering an entire herd to commercial decline with weight loss and malaise. To be eradicated, the animals must be destroyed so that transmission to the ground is halted. The virus dies off slowly in the ground but cannot propagate there. The only other viruses in the ground are green plant viruses and viruses in worms which, in our current state of knowledge do not infect any other but their host. FMV is about 30 nanometers in diameter, is a 20-sided icosahedron and has about 6 genes.

FMV last appeared in the U.S. in 1929. Before the mid-19^th century the scale of chronic damage in all countries was immense because its cause and means of quarantine were not known. There have been six outbreaks of FMV in the U.S. in the 20^th century. The worst epidemic was in 1914 when over 300,000 livestock were killed in 22 states. It was during these years that great attention began to be paid to disinfectants, a role taken over by the USDA (later transferred to the EPA in the 60s and 70s.)

FMV is inactivated on the ground and in stalls, barns and walkways by acids and alkalis (acetic acid, lime) and to a lesser extent by hypochlorite, which itself is inactivated by soil organic matter. EPA-registered disinfectants can be used to inactivate whatever contamination may occur indoors on hard non-porous surfaces and among these may be phenolics, halogens, oxidizing agents and aldehydes. Such disinfectants CANNOT be used as control measures in the farmland environment.

The virus cannot be studied in the U.S. except under the most severe quarantine conditions as at Plum Island off the coast of Long Island.

Please pay attention to the reentry forms you fill out on the airplane as you return to the U.S. from abroad. There is a reason why you have been asked all these years if you have set foot upon a farm or are harboring plant and/or animal material. The disease is endemic throughout the world and has recently surfaced in South Africa, Korea, Japan, Turkey and Taiwan. It came close to the U.S. when it appeared in 1947 in Vera Cruz at which time Mexican and U.S. agricultural personnel began a successful 7-year program of vaccination and slaughter. The U.S. has imported no live cattle from Great Britain since 1989 and in the year 2000 only 5 live pigs. Let’s hear it for the USDA!

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