The procedure to determine if an animal is infected with foot-and-mouth disease depends on, first, whether or not the animal is actually infected and, second, the stage of infection in a diseased animal.
Animals are isolated if they show symptoms of the disease: high temperature, lameness, lesions on the lips, tongue and feet.
Then there is a clinical examination of the animal on the premises, explained Dr Patrick J. O'Reilly, head of virology at the Department of Agriculture's Central Veterinary Research Laboratory at Abbotstown, Co Dublin.
The type of sample taken depends on the stage at which the animal is likely to have been infected.
An animal infected during the previous two to 14 days would show acute clinical signs, said Dr O'Reilly. Vesicles, blisters containing fluid, are visible on the animal's tongue, feet, mouth area and udder. These contain a high concentration of the virus.
This is very painful for the animal. It is sedated, and part of the blister is removed and sent for analysis.
If the animal was infected two or three weeks previously, the disease may have healed: no clinical signs would be showing.
In this case, blood samples would be taken which, once analysed, would reveal the antibodies produced by the animal to fight the disease.
For animals suspected of having the disease but which are not yet showing clinical signs, samples may be taken from their blood or milk which will be analysed for traces of the virus.
All samples are sent for analysis to the European and World Reference Laboratory for Foot and Mouth Disease, near London, which is the only authorised laboratory for the disease in Britain or Ireland.
The Department of Agriculture arranges to have samples dispatched to the laboratory. They usually arrive within "a matter of hours".
But testing time varies. A high workload in the laboratory could make the time longer. A positive result can be determined within a couple of hours.
However, if the first tests are not positive, there is a possibly lengthy procedure to prove a sample is negative. Dr O'Reilly said this could take a week to 10 days, depending on how much of the virus is in the animal's tissue.
