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The Horse |
Foot & Mouth Disease |
            
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It is a highly infectious viral disease in which fever is followed by the development of vesicles (blisters) chiefly in the mouth or on the feet. Cloven hooved animals such as cattle, sheep, pigs and goats are susceptible and some wild animal such as hedgehogs, coypu, rats, deer and zoo animals including elephants. Horses cannot contract the disease. There has only been one recorded case of FMD in a human being in Great Britain in 1966. The general effects of the disease in that case were similar to influenza with some blisters. It is a mild short lived, self-limiting disease. There is however a human condition called Hand, Foot and Mouth disease, which is unrelated. There are 7 main types of virus, which produce similar symptoms and which can only be differentiated in the laboratory ; O, A, C, SAT.1, SAT.2, SAT.3, and Asia 1. Within each type there are many sub-types, e.g. O1 and A22. The average incubation period is 3-8 days but it can be shorter or may extend to 14 days or longer. It has been confirmed that the virus responsible for the present outbreak is the highly virulent pan-Asiatic O type. When animals recover from infection by one type of virus they have little or no protection against attacks by any one of the others. Foot-and-mouth disease (FMD) is a highly infectious disease that can spread by direct or indirect contact with infected animals. Infected animals begin by excreting the virus a few days before signs of the disease develop. Pigs in particular produce large numbers of virus particles. Airborne spread of the disease takes place readily. The prevailing meteorological conditions and local topography determine the distance that the disease can travel and this may be considerable. For example, circumstantial evidence strongly suggests that the outbreak on the Isle of Wight in 1981 resulted from the airborne spread of the of the virus from Brittany in northern France. The disease is also spread mechanically by the movement of animals, persons, vehicles and other things, which have been contaminated by the virus. Meat from the carcase of animals infected with FMD at the time of slaughter can transmit the virus. In the past outbreaks of the disease have been linked with the importation of infected meat and meat products. How are horses involved in Foot and Mouth Disease?Though horses are not susceptible to infection by foot and mouth they may be involved in spreading infection. Material from an infected animal (dung, hair etc.) could be carried on hooves, bodies and tack of horses and by the rider. It could be carried from areas containing infected animals to previously "clean" areas. SymptomsThe incubation period is 2-21 days (average 3-8) although virus is shed before clinical signs develop. The rate of infection (morbity) can reach 100%, however mortality can range from 5% (adults) to 75% (suckling pigs and sheep). Recovered cattle may be carriers for 18 to 24 months; sheep for 1 to 2 months. Pigs are not carriers. Clinical signs in cattle are salivation, depression, anorexia and lameness caused by the presence or painful vesicles (blisters) in the skin of the lips, tongue, gums, nostrils, coronary bands, interdigital spaces and teats. Fever and decreased milk production usually precede the appearance of vesicles. The vesicles rupture, leaving large denuded areas which may become secondarily infected. In pigs, sheep and goats the clinical signs are similar but milder. Lameness is the predominant sign.
TreatmentThe virus can be destroyed by heat, low humidity, or certain disinfectants, but it may remain active for a varying time in a suitable medium such as the frozen or chilled carcase of an infected animal and on contaminated objects. There is no cure. It usually runs its course in 2 or 3 weeks after which the great majority of animals recover naturally. The justification of the slaughter policy is that widespread disease throughout the country would be economically disastrous due to the effects already noted above
PrognosisThe disease is rarely fatal, except in the case of very young animals, which may die without showing any symptoms. All affected animals lose condition and secondary bacterial infections may prolong convalescence. The most serious effects of the disease however are seen in dairy cattle. Loss of milk yield, abortion, sterility, chronic mastitis, and chronic lameness are commonplace. Countries with recent outbreaks of Foot & Mouth DiseaseThe disease is endemic in parts of Asia, Africa, the Middle East and South America, with sporadic outbreaks in disease-free areas. Countries affected by Foot and Mouth disease in the past twelve months include Butan, Brazil, Columbia, Egypt, Georgia, Japan, Kazakhstan, Korea, Kuwait, Malawi, Malaysia, Mongolia, Namibia, Russia, South Africa, Taipei, Tajikstan, Uruguay and Zambia. The last major outbreak of the disease in the EU was in Greece last year. Countries free of Foot & Mouth : North and Central America (north of Panama), Australia, New Zealand, Great Britain and Scandinavia. The European Union (EU) countries had been generally free of FMD until the recent outbreaks. FMD was last reported in 1929 in the U.S.A., 1952 in Canada, and 1954 in Mexico.
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