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By Elizabeth Stein, Margareti Medeiros, Laura Edison, Corrie Brown, Mário Celso Sperotto Brum, and Glaucia Kommers |
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By Elizabeth Stein, Margareti Medeiros, Laura Edison, Corrie Brown, Mário Celso Sperotto Brum, and Glaucia Kommers |
Foot and Mouth Disease
| Foot-and-mouth disease was first described in the sixteenth century in Italy. Then in the nineteenth century, it was observed in various other countries in Europe, Asia, Africa and the Americas. With the development of intensive agriculture at the beginning of the twentieth century, many countries felt a great need to control the disease and regulatory programs were devised. Currently, FMD is endemic in many regions of Asia, South America and Africa. In the last decade, outbreaks of the disease have occurred in several countries, including Greece, Taiwan, Argentina, Brazil, Uruguay, Japan and very recently, the United Kingdom, France, the Netherlands and the Republic of Ireland. Direct losses have been severe due to the killing of affected and in-contact animals although indirect losses have been even greater through the imposition of trade embargoes. |
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Etiology
The agent of foot-and-mouth disease is a virus in the family Picornaviridae, genus Aphthovirus.
Clinical signs
In general, clinical signs are most severe in cattle and swine. Sheep and goats often develop subclinical infection. Wild animals can have severe disease or be affected subclinically. Infected animals usually recover. FMD is not a killing disease.
Gross lesions
Pathogenesis
The incubation period, that is, the time from infection to the first sign of clinical disease, is 2-8 days.
Epidemiology
FMD is a highly contagious disease that infects all cloven hoofed animals. It spreads rapidly through susceptible populations.
Diagnosing the disease:
Because of the regulatory implications of the presence of FMD and its clinical resemblance to many other diseases, laboratory confirmation is essential. In most countries, the appearance of any vesicular disease entity must be reported to the authorities for adequate investigation. Government veterinarians are responsible for inspecting the clinically affected animals, collecting samples and sending these samples to federal laboratories for diagnosis.
Microscopic lesions
It is not possible to diagnose FMD based solely on the histologic appearance of the disease, as all vesicular diseases have similar histopathologic characteristics.
Differential diagnoses
All diseases causing oral or pedal erosions, slobbering, nasal discharge or teat lesions should be considered in the differential diagnosis of FMD.
Control
Control of FMD is based on three different sets of criteria:
FMD has the greatest economic impact of any animal disease.
