A Review of the BSE Epidemic in British Cattle

Abstract

Bovine spongiform encephalopathy (BSE) was first diagnosed in British cattle in 1986. The infectious agents of transmissible spongiform encephalopathy (TSE) diseases are believed to be infectious proteins or prions. They can remain infectious despite exposures to disinfectants, autoclaving, radiation, and ultraviolet light. TSEs affect animals as well as humans and are characterized by progressively severe psychomotor dysfunction and long incubation periods. As of August 27, 1999, 175,404 cases of BSE have been confirmed in Great Britain with 1,787 additional confirmed cases in Northern Ireland (as of August 31, 1999). Mathematical and statistical analyses of the BSE epidemic data suggest that the incidence of BSE in Great Britain and Northern Ireland will continue its rapid decline. Evidence relating to maternal and horizontal transmission of BSE is discussed. Public concern remains focused on the probable link between BSE infection in cattle and a new variant of Creutzfeldt‐Jakob Disease (vCJD) in humans, another TSE. Given the long and variable incubation periods associated with TSEs, and a possible genetic component, the eventual magnitude of this human epidemic remains uncertain.

Developments in microbiological risk assessment for drinking water

“…Kimberlin and Wilesmith (1994) suggested that BSE infection is transmitted through infectious`packets'. Evidence for a threshold effect is also supported to some extent by epidemiological data which show no evidence of horizontal transmission of BSE in cattle (Donnelly et al 1999). Horizontal transmission would include infection through contaminated pastures.…”

Human Culture, Ecological Change, and Infectious Disease:

“…An unusu-ally large number of new infectious diseases seem to have been identified in the past quarter-century. This includes the spectacular emergence and spread of HIV/AIDS and the somewhat mysterious occurrence of "mad cow disease" and its human equivalent, variant Creutzfeldt-Jakob Disease (Donnelly et al 1999). Patterns of land-useforest clearance, irrigation, and intensive agriculture-have engendered various new infectious agents, including several hemorrhagic fever viruses in Latin America (Morse 1995).…”

Outbreaks and Investigations

“…In 1986, veterinary pathologists at the Central Veterinary Laboratory in Weybridge, United Kingdom, became suspicious that a new disease was killing cattle (Donnelly et al, 1999;Matravers et al, 2000). Their suspicions were aroused by the microscopic appearance of the brain from a cow that died after exhibiting progressive abnormalities of behavior and movement that resembled those of sheep affected with the disease scrapie.…”