FMD is endemic in the Middle East; in Africa, excluding South Africa, Botswana, Namibia, and Zimbabwe and possibly Tunisia and Morocco; and in South America, excluding Chile, southern Argentina, Uruguay, Guyana, Surinam, and French Guiana.

A virus causes FMD. The virus is quickly inactivated outside the pH range of 6.0 to 9.0 and by desiccation and temperatures > 56 degrees C, although residual virus may survive a considerable time when associated with animal protein (the virus in infected milk will survive pasteurization). The FMD virus is resistant to lipid solvents such as ether and chloroform. Because of the sensitivity of the virus to acid and alkaline pH, sodium hydroxide, sodium carbonate, and citric or acetic acid are effective disinfectants.

Transmission of FMD is generally by contact between susceptible and infected animals. Infected animals have a large amount of aerosol virus in their exhaled air, which can infect other animals via the respiratory or oral routes. All excretions and secretions from the infected animal contain virus, and virus may be present in milk and semen for up to 4 days before clinical signs appear. Aerosol FMD can spread a considerable distance as a plume, depending on weather conditions, particularly when relative humidity is > 60% and when the topography of the surface over which it is dispersing does not cause turbulence. FMD has been transmitted to calves via infected milk, and milk tankers carrying infected milk have been implicated in the spread of disease between farms. The FMD virus can survive in dry fecal material for 14 days in summer, in slurry up to 6 months in winter, in urine for 39 days and on the soil between 3 (summer) and 28 days (winter).

Ruminants that have recovered from infection and vaccinated ruminants that have contact with live FMD virus can remain infected and carry the virus in the pharyngeal region for up to 2.5 years in cattle, 9 months in sheep, and probably lifelong in the African Buffalo.

The incubation period for FMD is 2 to 14 days, depending on the infecting dose, susceptibility of the host, and strain of virus. The clinical signs are more severe in dairy cows and intensively reared pigs than in sheep and goats, and FMD has frequently been ignored or misdiagnosed in small ruminants. After the incubation period, a fever of up to 106 degrees F develops, the animal is anorectic and salivates and stamps it feet as vesicles develop on the tongue, dental pad, gums, lips, and on the coronary band and interdigital cleft of the feet. Vesicles may also appear on the teats and udder, particularly of lactating cows and sows, and on areas of skin subject to pressure and trauma, such as the legs of pigs. Young calves, lambs, kids, and piglets may die before showing any vesicles because of virus-induced damage to the developing cells of the myocardium. Milk drops dramatically in milking animals, and all animals show a loss in condition and growth rate that may persist after recovery. Sheep and goats may develop only a few vesicles on the coronary band and in the mouth. Vesicles in the mouth, even when severe, usually heal within 7 days, although recovery of the tongue papillae takes longer. Lesions on the mammary gland and feet frequently develop secondary infections, resulting in mastitis, underrunning of the sole and chronic lameness. In pigs, the complete horn of the toe may be lost. Cattle and deer may also lose one or both horns of the foot.

The occurrence of FMD in countries previously free of the disease can have a major effect on local and international trading arrangements. Many countries free of FMD have a policy of slaughter of all affected and in-contact susceptible animals and strict restrictions of movement of animals and vehicles around infected premises. After slaughter, the carcasses are either burned or buried on or close to the premises, and the buildings are thoroughly washed and disinfected with mild acid or alkali and by fumigation.

There are other diseases which exist in the U.S. that show similar signs as FMD, such as Vesicular Stomatitis Virus, and Bluetongue Virus. It is important to have your veterinarian examine animals showing clinical signs described above. They can make the determination to bring in state veterinarians to investigate the situation further. FMD has been eradicated in the U.S. for quite some time, and we do not want to see it brought back. Thousands of animals were slaughtered, and its impact could be devastating to our livestock industry.