SCIENTISTS are still puzzled by the dramatic leap in the number of BSE cases on Irish farms in 1996 just when it appeared that the problem was almost resolved.
All the surveys have failed so far to come up with any real answers to the problem which has damaged Irish beef exporting capacity and cost the taxpayer millions of pounds.
The disease was first identified in Ireland in 1989, when there were 15 cases. Initially, most of the cases were found in imported animals or those fed on imported meat and bonemeal.
In 1990 there were 14 cases; 1991, 17 cases; 1992, 18 cases; 1993, 16 cases; 1994, 19 cases; and 16 cases in 1995.
The BSE crisis broke in March 1996; Irish incidence continued as normal but by July there were 16 cases. Then a flood of new cases of BSE began to emerge.
By the end of last year 74 cases had been recorded, more than four times the annual average. A discouraging factor was the emergence of the disease in animals born after 1990.
In 1990, the Department had banned the feeding to cattle of meat and bonemeal made from the bodies of cattle and sheep. The Government had moved one year earlier to ban the inclusion of what are known as Specified Risk Materials in food for humans.
The SRMs involve the organs of animals in which BSE is found.
Those studying the rising number of cases in the Republic, as they fell in Britain and Northern Ireland, concluded that contaminated meat and bonemeal were still being fed to cattle. Traces off meat and bonemeal were found in cattle feed.
Earlier this year the Department banned the feeding of meat and bonemeal from any source to cattle, and regulated the mills which compound animal feed so that food for cattle could not be processed at plants making feed for the pig and poultry industry, known as the white meat sector.
Pigs and poultry continue to be fed on meat and bonemeal made from animal carcasses, and cattle had been receiving meat and bonemeal made from chicken offal. Now this can be done only under licence.
If what the scientists believe is true, it could take another four to five years before the Republic can claim to have a BSE free herd because of the long incubation period of the disease - four to nine years on average.
But are there other factors influencing the increase in numbers here since the BSE crisis broke? There is growing evidence that some of the BSE cases presented to the Department of Agriculture had come from elsewhere, probably across the Border.
At least three farmers in the Republic are under investigation by the Department's anti fraud team, which had a crucial role in stamping out the use of angel dust.