Descriptive spatial analysis of the epidemic of bovine spongiform encephalopathy in Great Britain to June 1997

This was a spatial analysis of the epidemic of bovine spongiform encephalop athy (BSE) in Great Britain, based on agricultural census data collected be tween 1986 and 1996 and BSE case data collected up to lune 1997. Kernel smo othing techniques were used to plot the distribution of BSE-positive cattle holdings per inn holdings per square kilometre and the distribution of con firmed BSE cases per inn head of cattle per square kilometre. In the early stages of the epidemic reported BSE cases were scattered widely throughout Great Britain, with no clearly identifiable Focus. By June 1997, a statisti cally significant cluster of BSE-positive holdings was identifiable in the eastern part of the South west region of England. During the epidemic the h ighest densities of confirmed BSE cases per ton cattle per square kilometre occurred in the greater part of the South west region of England and withi n Dyfed in the south west of Wales. In Wales, a small number of holdings ex perienced large numbers of confirmed BSE cases. In the South west region of England a large number of holdings experienced small numbers of confirmed cases. By lune 1997. the distribution of BSE-positive holdings across Great Britain was largely determined by factors that influenced the amount of re cycled infectious material they were exposed to.