Bovine spongiform encephalopathy (BSE)--a review
1998
Blanchfield, J.R.
Bovine spongiform encephalopathy (BSE) incidence. The number of new cases continues to fall as forecast (from the peak of 37487 in 1992 to 13825 in 1995, to 7406 in 1996 to 3980 in 1997) and is on track to bring the epidemic to an end. BSE/nvCJD. Findings since 1996 indicate that the agents of BSE and new-variant Creutzfeldt-Jakob disease (nvCJD) possess the same 'fingerprint'. This is consistent with the transmission of BSE infection to humans. Although it remains possible that both BSE and nvCJD may have been triggered by some currently unknown cause, it is difficult to conceive what that might be. nvCJD incidence. The UK Department of Health reported 24 cases of nvCJD up to the 6 April 1998. Assuming that nvCJD is the result of consumption of BSE infective materials before 1989, it is too soon to draw any conclusions about likely future incidence. Infectivity of bovine materials. In its report dated 9 December 1997, the EU Scientific Steering Committee has set out the most up-to-date information and assessment of the infectivities of various bovine materials. Beef, milk and bones. Assays in mice have not detected BSE infectivity in muscle meat (beef) or milk from confirmed cases. The more sensitive assay in calves is yet to be concluded, but to date results are negative. Thus, although low levels of infectivity cannot be excluded, the risk from beef or milk is currently considered to be extremely small. Calf experiments have detected infectivity in the dorsal root ganglia, the trigeminal ganglia and the bone marrow. The risk involved to people eating beef is extremely low, about one case of nvCJD in a billion years per person. However, this estimate has a wide range of uncertainty, and the UK government has responded by banning the sale of beef on the bone.
显示更多 [+] 显示较少 [-]