Molecular epidemiology of the human immunodeficiency virus type 7 in Santiago, Chile

Background: Most of the studies of HIV-1 infection in South America have be en limited to Brazil and little is known about the viral variants that ar c ausing disease elsewhere in the continent. Aim: To determine the characteri stics of the viral variants present in Chile as well as patterns of viral t ransmission. Material and methods: Viral sequences were obtained form 21 HI V-1 infected people from Santiago, Chile who were infected either via sexua l contact or intravenous drug use. Cloned sequences obtained from both the third variable and conserved regions of the envelope as well as the viral p rotease were evaluated. Results: We found only clade B subtype viruses in S antiago. An evaluation of the envelope gene revealed no evidence that the s equences were monophyletic by risk group. A number of the protease sequence s were predicted to encode amino acid substitutions commonly found during s election for protease inhibitor resistance. Conclusions: The HIV-1 strains studied in Chile, belong to the subtype B. There is no molecular evidence o f separate introductions of the virus into the different risk groups. A num ber of substitutions in the protease gene that may confer resistance to pro tease inhibitors were found in patients with no previous exposure to this c lass of drugs.