A virus that is highly infectious and causes fever and blister-like sores

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The Independent Online

Can humans catch foot-and-mouth from infected animals? What are the effects?

Can humans catch foot-and-mouth from infected animals? What are the effects?

Only rarely, by handling them. The effect is temporary, and mild. You cannot usually catch it from eating infected meat. You can, however, catch it if the virus reaches your mouth - so infected milk can pass it on.

What causes foot-and-mouth disease?

A virus, transmitted in air, fluids that leak from diseased blisters, faeces and urine. It can also be carried by dust, vehicles and clothes of people coming into contact with animals.

"The virus is highly infectious and expelled in breath," said Tim Miles, the veterinary manager of the Meat and Livestock Commission. "Where pigs are packed together plumes can form above them, spreading the virus up to 60 kilometres [37.5 miles] downwind." Pigs are potent excretors of the virus.

How dangerous is it?

It is not generally lethal to adult animals - the mortality rate is about 1 in 20 animals, though higher in the young. However, it causes fever and painful fluid-filled blisters on the tongue and mouth (making the animal salivate), and blisters on the feet, teats and udder. Milk yields drop significantly, and animals become lame.

What animals does it affect?

All cloven-hoofed animals - including cattle, sheep, pigs, goats, camels, alpacas and deer. Horses are not susceptible.

How long is the incubation period? How long are animals infectious?

For disease control, the incubation period is taken to be 14 days before blisters appear - so infected animals' movements and contacts over that period must be tracked down, and any animals they may have infected must be isolated.

Virus transmission can commence up to 10 days before the appearance of blisters. The primary method of transmission within herds and flocks is by direct contact, or via exhaled air and excreted fluids. Eradicating foot-and-mouth disease is thus a huge administrative headache, and can cost millions.

How common is it?

"FMD", as it is called in the livestock industry, is widespread, especially in the major livestock-producing countries of the world. It is well established in the Commonwealth of Independent States (of the former Soviet Union), Russia, Turkey and the Middle East, Asia, Africa and some areas of South America.

Most of western Europe is free, but recent outbreaks have occurred in Italy (1993) and Greece (1994). It was last recorded in Australia in 1872.

How long does it linger?

FMD virus may remain infective in the environment for several weeks. The post-treatment of carcasses normally renders it inactivate within three days, but it has been detected in milk and semen for up to 56 days after infection. Some recovered animals remain long-term carriers.

How do you get rid of it?

The abattoir where it was discovered will be completely sterilised, and the livestock probably slaughtered. Herds containing infected animals will be slaughtered and burnt.

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