The Clinical Picture in Slow Virus Diseases: A Review

Abstract

The degenerative slow virus diseases are classified by whether the causative virus is conventional or unconventional. The conventional viruses are those whose elementary body consists of either RNA or DNA and is contained within a protein coat. These viruses cause slow infection because of an abnormality in the ability of the virus to replicate itself normally, as is the case in subacute sclerosing panencephalitis, or because of an abnormality in the host's immune response, as in progressive multifocal leukoencephalopathy. The conventional viruses have not yet been shown to be transmissible. The unconventional viruses are infectious agents which have properties not usually shown by conventional viruses. They induce slowly evolving diseases which share common neuropathic changes . These viruses cause the subacute spongiform virus encephalopathies. In humans they are responsible for kuru, the familial and sporadic forms of Creutzfeldt-Jakob disease and familial Alzheimer's disease. Similar transmissible diseases have been found to occur naturally in animals, and there is some feeling that in certain individuals, notably farmers, the virus causing Creutzfeldt-Jakob disease may be transmitted from sheep and goats (2).