Kvet Forum
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FMD is endemic throughout many parts of the world, but much of Europe, North America, Australia and New Zealand is free of the disease. Disease incursions are eliminated by stringent herd and flock slaughter programmes and livestock movement bans.
Aetiology
FMD is an extremely contagious disease most commonly spread by movement of infected cattle, sheep, goats and pigs, but indirect spread via farm staff and vehicles is important in many outbreaks.
Clinical Presentation
The incubation period is 2–10 days. Initially, one or two cattle present with pyrexia (>40.0°C), depression, anorexia, a marked drop in milk yield and salivation. Other cattle in the group at pasture may not yet show clinical signs, but the increase in disease morbidity within 24 hours in housed cattle is very dramatic.
Vesicles on the tongue, dental pad and hard palate quickly rupture, leaving shallow ulceration with shreds of mucosa at the periphery. The submucosa is markedly hyperaemic. There are no ocular or nasal discharges.
Vesicles may be present on the teats and at the coronary band. They may become secondarily infected and cause lameness. Cattle under intensive management conditions with appropriate supervision would be detected at this stage, and in countries attempting eradication of FMD, compulsory slaughter of all cloven-hooved animals on the farm would ensue.
Where cattle are not slaughtered, the mouth ulcers start to heal by day 10 after infection. Foot lesions often become secondarily infected and animals may be reluctant to rise. During the acute phase of disease there is marked weight loss and milk yield reduction.
Differential Diagnosis
- Group of cattle: Bluetongue; Rinderpest.
- Individual cattle: Malignant catarrhal fever; Bluetongue; Ingestion/contact with acaustic substance.
Diagnosis
Overlying mucosal flaps >2 square cm from a ruptured vesicle are dispatched in appropriate transport media to a designated laboratory for confirmatory diagnosis.
Management
In countries attempting eradication of the disease, cattle with suspected FMD are slaughtered immediately. In other countries, where there is no compulsory slaughter policy, antibiotic therapy may control secondary bacterial infection of ulcers.
Biosecurity measures are essential during FMD outbreaks in order to prevent spread of disease. Vaccination against the strain of FMD virus implicated in an outbreak is effective, but it incurs trade restrictions to many countries.