8. FOOT AND MOUTH DISEASE
Foot and mouth is a highly contagious and nasty viral disease. However, whilst it infects most animals in a herd, it actually kills only a small percentage.
It is caused by an aphthovirus which can survive in pickled meats for one to two months, and parma ham for three to five months. It is not always killed by pasteurisation and it may be in dried milk for years.
Foot and mouth’s tell-tale symptom is sudden lameness, the feet being very painful. A pig’s back may arch and the animal becomes unwilling to move. Blistering occurs on the nose, tongue, lips and feet, hence the name foot and mouth.
The high concentration of virus produced in the early stages of the disease, before symptoms show, coupled with the large number of pigs crowded together and forced ventilation in factory farms, gives rise to large viral plumes which can travel by air for long distances. The virus may then infect other pigs and cloven-hoofed species, such as cattle, sheep, goats and deer.
The virus is also spread by infected animals touching healthy animals, by manure on lorries, markets and farms, or carried on clothing. Milk may also be a source of infection.
Pigs do not remain carriers of the disease, and are free from the virus 28 days after infection. Many question, therefore, why the animals infected with foot and mouth are killed at all.