Foot and Mouth Disease

Foot and Mouth Disease (FMD) is seldom fatal, typically only causing mortality in younger animals. However, the virus can damage the host so profoundly that an affected animal may be unable to completely recover.

Mortality in younger animals is most often the result of acute myocarditis.

Infected animals typically show clinical signs 2-14 days after exposure, generally taking 3-5 days to develop, during which time the animal will become feverish and depressed.

However, the most recognized symptoms are lesions which will develop around the oral cavity, lips and tongue, as well as on the feet, between the hooves, and on the mammary glands in females.

Oral lesions are typically accompanied by excessive salivation best described as viscous and foamy. Given that these lesions can become quite painful the affected animal may experience a loss of appetite, eventually leading to anorexia. The decrease in food intake can result in decreased growth and decreased milk production. Furthermore, malnourished animals are also immunosuppressed which can predispose an affected animal to secondary infections. Secondary infections are quite common considering the number of open lesions exposed to pathogens in the environment. Such infections can significantly prolong recovery.

Foot lesions can become painful enough to impede locomotion. Animals will become reluctant to move and will thus spend less time grazing, further contributing to the decreased food intake.

Mammary lesions not only act as a source of vertical transmission, but if such lesions are painful, the dam may be less willing to feed her young. Pregnant animals may also become infected. In such cases abortion may result.

Although a recovering animal will likely regain any lost weight, milk production rates remain lower than normal. Combined with the rise in abortion rates and fatalities among younger animals, the damage caused by this disease is quite significant. Due to the rapid rate of transmission and the extent to which this disease can impact the economy, any suspected cases must be dealt with as quickly as possible.