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Monday, 11 May 2015

Foot and Mouth Disease
·         The disease is endemic throughout the world however much of Europe, N America, Australia and New Zealand are disease free.
·         In 2001, a severe outbreak occurred in the UK costing around £3billion. It was caused by the Pan Asia strain, first isolate in India in 1990. In 2007, the virus escaped from a vaccine facility in England and spread locally. Movement restrictions had a severe impact on the farming industry.
·         Cattle are at the greatest risk for this disease. Sheep, goats and pigs can also become infected.
·         
Spread: the virus is extremely contagious. It is most commonly spread by movement of infected cattle, sheep, goats and pigs; however, indirect spread via farm staff and vehicles is considered to be an important means of transmission, as in 2001. Wind-borne spread of the disease is believed to be the reason that cattle on the Isle of White were infected by pigs in Brittany.

·         Clinical presentation: the virus has an incubation period of 2 – 10 days. Initially, a few cattle present with the following symptoms… fever (>40*C), depression, loss of appetite, drop in milk yield and salivation. When housed with others, after around 24 – 48 hours, the others start to show clinical signs.
Vesicles (fluid-filled blisters) on the tongue, dental pad and hard palate quickly rupture, leaving shallow ulceration with shreds of mucosa on the top layer. The underlying tissue is reddened and painful. These vesicles may also be present on the teats and coronary band. The latter can become secondarily infected, causing lameness. There is no ocular or nasal discharge.
Upon discovery at this stage, cattle would be euthanized. FMD does not kill cattle but the time taken to recover after infection is several weeks, at which point the condition of the cattle will have markedly deteriorated; production and weight will have plummeted, along with moving restrictions being applied to that farm.
In sheep, FMD may present as sudden onset of lameness; however, CODD and footrot should be presumed firstly.

·         Differential diagnosis
… for cattle in groups: bluetongue or caustic substances.
…for individual cattle: mucosal disease, malignant catarrhal fever, bluetongue or ingestion/contact with caustic substance. (caustic: chemically burning/degrading)

·         Diagnosis: where disease is suspected the farm must: inform the Police and Divisional Manager of Animal Health, not leave the premises and stop all movement of people, vehicles and animals onto and off the premises.

·         Treatment: in the UK, FMD animals are euthanized immediately. In countries with no slaughter policy, antibiotics are used to control secondary bacterial infections of ulcers.


·         Prevention/Control: biosecurity control methods, strict movement restrictions, culling and strategic vaccination is often implanted nation-wide in order to prevent a repeat of 2001’s devastating outbreak effects.


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