EPIDEMIOLOGY OF BOVINE SPONGIFORM ENCEPHALOPATHY IN NORTHERN-IRELAND 1988 TO 1995

The epidemiology of bovine spongiform encephalopathy (BSE) in Northern Ireland from 1988, when it was first confirmed, to the end of 1995 is described, All cases of BSE were subjected to a detailed epidemiologi cal investigation, complemented by data from the national animal healt h records on every bovine animal, Data are presented on 1680 cases, Ma ny of the epidemiological features of the disease were similar to thos e reported in Great Britain, but the incidence in Northern Ireland was approximate ly one-tenth that in Great Britain. The epidemic increase d to a peak of 56 cases per month in January 1994, and decreased to ni ne cases in December 1995. Statutory intervention banning the use of m eat and bone meal in ruminant feed in January 1989 has produced a mark ed and continuing reduction in the incidence, The majority of the case s were in Northern Ireland cattle, but 83 cases were imported from Gre at Britain and five from the Republic of Ireland. Many of the key epid emiological features have remained constant throughout the epidemic: t he greater incidence of BSE in dairy herds than in beef suckler herds, the low within-herd incidence, the variation in incidence with herd s ize, the breed distribution, the distribution of the reported clinical signs and the proportion of purchased cases, Although the source of t he BSE epidemic in Northern Ireland has not been established conclusiv ely, the evidence suggests that the importation of meat and bone meal and protein concentrates from Great Britain may have been responsible.