Human immunodeficiency virus and the nervous^system: some aspects of the molecular pathology

Abstract

Human immunodeficiency viruses (HIV-1, HIV-2), human T-cell lymphotrophic virus (HTLV-1, HTLV-2) which cause disease in human beings are retroviruses which belong to the group now referred to as lentiviruses, a sub-family of animal and human retroviruses capable of producing after usually prolonged incubation period, chronic diseases of the nervous system .'The incubation period between HIV infection and the development of antibodies may be up to 6 months and during this period, the patient can transmit the infection while sero-egative. The mean incubation period between HIV infection and the development of AIDS is about 10 years. Probably about 10 million people world- wide are infected and over a quarter of a million AIDS cases including over 50,000 from African countries have been reported to the WHO . The neurological complications of HIV infection are very frequent and with a wide spectrum (sec Table 1 according to a WHO consultation 1990)(1) and the timing of occurrence could vary from early to late in the course of the infection. HIV infects the central nervous system in 90% of patients dying of AIDS. The virus, and not intercurrent infection is the direct cause of the sub-acute encephalomyelites that produces the AIDS dementia complex found in terminally ill patients. The virus has also been found in the CNS of patients with myelopathy although the mechanism by which the myelophathy is caused is still unclear.