Dr Andrew Tucker – Charles Street Veterinary Consultancy
Foot-and-mouth disease is a viral disease (aphthovirus) which in pigs is acute and very contagious. It is characterised by fever, the formation of vesicles on the coronary band (between leg and claw) as well as on the snout, lips and tongue. Although mortality due to foot-and-mouth is quite, low the number of pigs affected in the herd will be high (due to it been very contagious).There are seven different foot-and-mouth virus serotypes: European (Types A,O,C), South African (S.A.T. 1,2,3) and Asian (Type 1). These serotypes are then further divided into about 65 subtypes. Knowing the type and subtype goes a long way in helping find out where an outbreak might have come from.
Infection takes place predominantly by inhalation or ingestion. The incubation period is two to seven days and the virus is shed even before the appearance of lesions.
How do you know if it’s on your farm?
Normally the first sign noticed on farm is a sudden onset of severe lameness. An accompanying fever may be noticed as pigs are lethargic and do not want to eat. Vesicles which rupture to form ulcers are normally seen on the coronary bands as well as the tongue, lips, snout and teats. None of these signs are specific for foot-and-mouth only, but should be reported and investigated straight away due to the implications if it is foot-and-mouth.
So please contact your vet immediately if you notice any of these signs. Diagnosis will have to be confirmed via blood tests.
How do you treat or prevent it?
Biosecurity is a much spoken about topic in our industry and in situations like a foot-and-mouth outbreak the farms with poor biosecurity are at huge risk and therefore also pose a huge risk to the whole industry.
The virus is spread by direct and indirect contact with affected animals, carcasses or animal products. Interestingly this virus can remain alive in a product like Parma ham for three to five months.
Passive human carriage occurs and can be prevented by change of outer clothing and showering. Transmission via the aerosol route is possible, which highlights why lawn mowers work better than sheep to control the grass around the unit. Although fences cannot stop the virus entering the unit, they go a long way in lowering the risk.
Proper biosecurity will reduce the risk of getting this disease on your farm to a minimum. See compartmentalisation or SAPPO Quality Assurance documents www.sapork.com
Any positive cases are dealt with by the state veterinary department. The reason for this is that South Africa is ‘free’ of this disease, except for a controlled area around Kruger National Park and the present Northern KwaZulu-Natal outbreak.
Many countries are negative and hence outbreaks have implications on meat/animal exports. For these reasons this is a “government controlled” disease and any suspected cases have to be reported to them.
Outbreaks will be dealt with either by a slaughter out programme within a designated quarantine area or via vaccination in this area. This decision lies with the state veterinary department.
Pig Diseases – D.J.Taylor; Diseases of Swine – Straw, Zimmerman, D’Allaire, Taylor