The insidious spread of a disease that incapacitates before it kills

More cases of BSE are being identified in the Republic, but only, say scientists, because our testing methods have improved. Sean MacConnell, Agriculture Correspondent, reports

BSE is a disease of adult cattle which is progressive and fatal, and was first identified in the Republic in 1989. One of a family of similar diseases, Bovine Spongiform Encephalopathy is caused by an abnormal formation of a normal brain protein. The infection of the central nervous system causes agitation in the animal and later, infected animals lose mobility which led to the common name "mad cow disease".

The first case of the disease was identified in Britain in 1986 and scientists concluded that it was probably triggered when infected sheep brain was incorporated in cattle feed some years before.

During the oil crisis of the 1970s, meat and bonemeal manufacturers had changed the system of rendering animal carcases to meat and bonemeal, to save energy costs. All that was necessary to spread the disease was the incorporation of the first diseased animal into the cattle feed chain, because less than two grammes of infected meat and bonemeal can cause the disease in cattle.

In 1989, there were 15 cases of BSE in the Republic, mainly in cattle imported from Britain and in herds along the Border, where cattle feed from Britain was used.

The Government's response to BSE was swift and it imposed the European ban on feeding meat and bonemeal to cattle and sheep, and the importing of animals from Britain. It also decided that it would fully compensate farmers whose herds had been hit by the disease and would remove all the animals from the land.

This was contrary to the advice of British veterinary experts, who had advised its government to remove only the infected animal and compensate for the loss of that animal. And earlier this month, the French food authority advised its government to stop destroying entire herds and instead cull just the affected animals.

The Department of Agriculture here says its slaughter-all policy is subject to ongoing review.

There was no upsurge in the number of BSE cases in the Republic until 1996, with fewer than 20 cases a year being recorded. However, there was a major marketing problem when, in March 1996, scientists confirmed that there was evidence of a possible link between variant CJD in humans and BSE.

It has been unkindly suggested that beef prices had fallen so low that it became more profitable in 1996 to report cases of BSE and claim compensation, rather than conceal them.

At any rate, the number of confirmed cases jumped from 16 in 1995 to 74 in 1996, and that annual total has continued to rise ever since (see graph). The most dramatic leap in confirmed cases came after 2000, when the EU instructed all member states to test for the disease in injured and sick animals which were not destined for the foodchain and had previously been ignored.

The EU regulation that all cattle over 30 months old destined for the food chain should also be tested meant that for the first time a truly accurate picture of the level of the disease in the Irish herd could be established.

In 2000, there were 149 confirmed cases of BSE; last year, the total jumped to 246 and half of these cases were found by active surveillance, when over 660,000 tests were carried out. Last week, the running total for the year reached 260. Scientists say that this increase in the number of cases being identified does not indicate increased exposure, but an increased ability to identify cases in the cattle population. From a consumer's point of view, the bottom line is that since 1989 all the material from animals going into the foodchain which could infect humans has been removed, preventing the risk of humans being infected with CJD.