Spongiform encephalopathy in a greater kudu (Tragelaphus strepsiceros) introduced into an affected group

Bovine spongiform encephalopathy

Bovine spongiform encephalopathy is an infectious disease of cattle that is transmitted through the consumption of meat-and-bone meal from infected cattle. The etiologic agent is an aberrant isoform of the native cellular prion protein that is a normal component of neurologic tissue. There currently are no approved tests that can detect BSE in live cattle.

Bovine spongiform encephalopathy infectivity in greater kudu (Tragelaphus strepsiceros)

Of all the species exposed naturally to the bovine spongiform encephalopathy (BSE) agent, the greater kudu (Tragelaphus strepsiceros), a nondomesticated bovine from Africa, appears to be the most susceptible to the disease. We present the results of mouse bioassay studies to show that, contrary to findings in cattle with BSE in which the tissue distribution of infectivity is the most limited recorded for any of the transmissible spongiform encephalopathies (TSE), infectivity in greater kudu with BSE is distributed in as wide a range of tissues as occurs in any TSE. BSE agent was also detected in skin, conjunctiva, and salivary gland, tissues in which infectivity has not previously been reported in any naturally occurring TSE. The distribution of infectivity in greater kudu with BSE suggests possible routes for transmission of the disease and highlights the need for further research into the distribution of TSE infectious agents in other host species.

What went wrong in BSE? From prion disease to public disaster

The recent report of 10 cases of a new variant of Creutzfeldt-Jakob disease (CJD) which could be related to bovine spongiform encephalopathy (BSE) has precipitated alarm throughout Europe. The beef trade in the UK has collapsed and the European beef market has been seriously damaged. What went wrong? Much of the difficulty of handling the BSE epidemic arose from the 4-5 year incubation period which made it difficult to ascertain whether measures taken to contain the epidemic had been effective. Public consternation and scientific equivocation arose because these prion diseases are unlike any other group of infectious diseases. Rather than being caused by a conventional micro-organism, the primary pathogenic event consists of the transformation of a normal protein (the prion protein) into an abnormal form, which can transmit disease. Prion disease is endemic in humans and sheep where it is associated with polymorphisms or mutations within the prion protein gene. Although the disease in these cases arises spontaneously, it produces an infectious prion protein. Under certain circumstances, abnormal prion protein contaminates other animals or humans resulting in epidemics of acquired prion disease. This review describes the events of the BSE epidemic and considers the difficulties in assessing the current risk to human health.

[Transmissible animal spongiform encephalopathies. Epidemiologic aspects]

This article presents an update of data about the transmissible spongiform encephalopathies which affect some animal species, particularly bovine spongiform encephalopathy in Great britain and in other countries where this disease is sporadic. The genetic susceptibility of scrapie in sheep and the natural transmission of these spongiform encephalopathies are discussed. The control measures for public health and animal health are presented.