AIDS-related progressive multifocal leukoencephalopathy (PML): a retrospective study from Pretoria, South Africa.

In HIV-positive patients during the pre-HAART (highly active antiretroviral therapy) era, infection by the JC virus in the brain with PML was rapidly fatal, with a median survival of 3 - 6 months; up to 5% of HIV-positive patients eventually succumbed to PML. Of fatal central nervous system (CNS) diseases, PML occurs in up to 18% of patients. [2] In the USA and Europe, seroprevalence studies have shown that 60 - 80% of adults have antibodies against the JC virus; a minimum of 7 viral genotypes may be identified according to the sequence analysis of the major capsid protein (VP1). It has been shown that the major type of JC virus in the USA is JCV1, while type 4 is seen in Europe and the USA, type 2 in Asia, and types 3 and 6 appear to be prevalent in western Africa. [3]