Foot and Mouth

FASCIOLIASIS - FOOT AND MOUTH DISEASE

Foot and mouth disease is an extremely infectious viral disease of cloven hoofed animals and occasionally human. The disease is widespread from Africa to South America, from Middle East to Asia. Foot and mouth disease virus consists of seven serotypes (A, O, C, SAT 1, SAT 2, SAT 3 and ASIA I) and within each serotype there are further sub-types. The virus is extremely infectious and susceptible animals may be infected by ingestion of inhalation of the virus by nearby infected animals, virus contaminated environment or in food which contains uncooked animal tissues. The virus can be transferred from place to place on vehicles, clothing, etc. It can even be wind-borne for a long distance in cool-humid conditions.

Because of the highly infectious nature of the disease, strict control needs to be carried out. In non-endemic areas, e.g. Europe, the disease is controlled by a slaughter policy. In endemic areas, vaccination may be the most effective way to protect animals from the disease. Animals at risk should be vaccinated at least twice a year with vaccines against local virus serotypes and subtypes. In the event of an outbreak, strict hygienic measures should be used to minimise the spread of the disease. Feed and bedding of infected animals should be destroyed. Premises where the disease has occurred should be thoroughly disinfected and access to these should be restricted.

Because of the serious consequences of the disease, veterinary authorities should always be informed when a clinical case is suspected.

Clinical signs:

Fever is the first clinical sign. Affected animals generally have depression and anorexia. A sudden milk drop can be observed on lactating animals. A day or so later, small vesicles develop in the feet and in the mouth, or on teats. The vesicles are initially small but are rapidly enlarged with a raised, blanched surfaces. About a day later, the vesicles rupture and release straw coloured fluid leaving raw painful ulcers. The lesions cause lameness, excess salivation and reluctance to eat, but heal within about ten days. However, secondary bacterial infection in feet lesions may cause complications and deformities such as shedding of the hooves. Although the disease is extremely infectious, there are only 5% of the clinical cases die which are more likely to be young animals. In endemic areas, infected indigenous cattle may have a mild course of the disease and recover in a few days. Susceptible animals, however, may be seriously affected causing significant losses in milk and meat production and infertility.

Treatment:

In endemic areas, local antiseptic treatment of the lesions combined with antibiotics are administered to minimise the risk of secondary infections. In most of the non-endemic areas, usually no treatment is used and the disease is controlled by slaughter policy.

Control measures:

Vaccination is the most commonly used method in the control of CBPP. The most effective vaccine in use is the one based on live mycoplasma organisms. However, it causes difficulties in practice because the strains that are mild enough to be used safely are not good at stimulating immunity, while those good one can usually cause severe reactions. These vaccines can not confer life-long immunity, and hence need to be repeated every year. Effective control of CBPP needs to combine vaccination with other control measures. For instance, when moving cattle into a new area, all the cattle should be monitored strictly and those positive ones should be removed. In non-endemic areas, if it is affordable, the CBPP cattle should be slaughtered to stop the spread of the disease.

WWW Sites of Relevance

World Organisation for Animal Health