Foot and Mouth Disease
Foot and mouth disease is endemic throughout many parts of the world but much of Europe, North America, Australia and New Zealand are free of disease.
A very severe outbreak of FMD occurred in the UK during 2001 costing in excess of £3 billion. The FMD 2001 outbreak in the UK was caused by the Pan Asia strain first isolated in India in 1990.
In 2007 FMD virus escaped from a vaccine facility at Pirbright, England causing disease on adjacent farms. Movement restrictions had a severe economic impact on the farming industry.
FMD is extremely contagious and most commonly spread by movement of infected cattle, sheep, goats, and pigs but indirect spread via farm staff and vehicles was considered important in many cases during 2001.
Wind-borne spread of the virus over 250 km was believed to be cause of infection when pigs in Brittany infected cattle on the Isle of Wight.
The incubation period is 2-10 days. Initially, one or two cattle present with fever (>40.0°C), depression, loss of appetite, marked drop in milk yield and salivation. When housed or closely confined, other cattle in the group show clinical signs over the next 24-48 hours and such spread is dramatic.
Initially one or two cattle become isolated and present with fever (over 40.0°C) and depression.
Ear ly signs of FMD include salivation.
Ther e is marked salivation associated with vesicles in the mouth with rapid spread of infection to other cattle in direct contact.
Ruptured vesicles (fluid-filled blisters) on the tongue revealing reddened and painful ulceration with shreds of mucosa at the periphery.
Vesicles (fluid-filled blisters) on the tongue, dental pad and hard palate quickly rupture leaving shallow ulceration with shreds of mucosa at the periphery. The underlying tissues are reddened and painful.
Ruptured vesicle on the tongue - several days' durat ion.
Vesicles may be present on the teats and at the coronary band. The latter can become secondarily infected, causing lameness.
Ruptured vesicles on the teat - FMD has been probably been present for more than 3-5 days.
Ruptured vesicle at the coronary band. This lesion would have caused severe lameness.
There are no ocular or nasal discharges. Cattle under intensive management conditions with appropriate supervision would be detected at this stage, and in many countries compulsory slaughter would ensue. During the acute phase of disease, there is marked weight loss and milk yield reduction. Foot lesions often become secondarily infected and animals are very lame and often may be reluctant to rise.
Where cattle are not slaughtered at an early stage, the ulcers start to heal by around day 10 after infection but recovery takes several more weeks, during which time the animal will have lost a great deal of condition. FMD does not kill cattle; it is the devastating effects on production and weight loss that is so important. Trade restrictions also greatly influence political decisions about control policy.
For disease in groups of cattle your veterinary surgeon will also consider:
- Caustic substances
- Mucosal disease
- Malignant catarrhal fever
- Ingestion/contact with caustic substance
Malignant catarrhal fever usually affects only one animal in the group. There are severe ocular signs and crusting of the muzzle.
Where disease is suspected, you must inform the Police and Divisional Veterinary Manager of Animal Health (formerly State Veterinary Service). Do not leave the premises and stop all movement of people, vehicles and animals onto and off the premises.
- Inform the Police and Divisional Veterinary Manager of Animal Health
- Do not leave the premises
- Stop all movement of people, vehicles and animals onto and off the premises.
Overlying mucosal flaps >2 square cm from a ruptured vesicle are despatched in appropriate transport media to a designated laboratory.
Severe, advanced lesions on the hard palate of a sheep.
Ulcers on the hard palate beginning to heal.
FMD may present as sudden and severe lameness in sheep.
Ear ly footrot lesions (this case) causing severe lameness must be differentiated from FMD.
Sloughing of the hoof capsule caused by contagious ovine digital dermatitis (CODD).
In the UK, cattle with suspected FMD have been slaughtered immediately. In other countries where there is no slaughter policy, antibiotic therapy may control secondary bacterial infection of ulcers but recovery takes several weeks to months.
Management Prevention Control measures
Control measures are determined nationally. Slaughter of all cloven-hooved animals on the farm with full compensation operated in the UK during the 2001 FMD epidemic. The 3 km contiguous cull proved very contentious especially in Scotland during this outbreak.
Slaughter of ewes and young lambs in 2001 as part of the contiguous cull. It is unlikely that such measures would be undertaken again.
The 2007 outbreak of FMD was traced to poor biosecurity measures at Pirbright. Slaughter of all cloven-hoofed animals on the affected farms with full compensation again operated but there was no contiguous cull. Ring vaccination was considered but not used, presumably due to the known origin of the source. Poor disease surveillance in the first instance and protracted draconian control measures implemented on a national basis, caused unnecessary hardship to many sectors of the livestock industry.
Bio-security measures which were being operated by farmers and allied industries during FMD outbreaks were quickly abandoned after the end of the epidemic.
It is not clear what control policy will operate should another outbreak of FMD occur in the UK.
Biosecurity measures operated by farmers and allied industries during FMD outbreaks were quickly abandoned after the end of the epidemic and there are no disease control precautions on most farms in 2011.
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