HIV-1 subtype C dissemination in southern Brazil.
OBJECTIVE
To describe the molecular and epidemiological profile of HIV-1 in patients followed at the University Hospital of Rio Grande, Brazil.


METHODS
A cross-sectional study was conducted from September to December 2002. Plasma viral RNA of 85 patients was extracted and protease and reverse transcriptase genes were polymerase chain reaction-amplified and sequenced. Sequences were subtyped and examined to antiretroviral resistance mutations. Laboratory data and past history of antiretroviral treatment were also collected.


RESULTS
Most viruses were either subtype B (42%) or subtype C (45%). No risk behaviour, sexual orientation or laboratory parameter was associated with any specific subtype, but subtype C tended to be more frequently found in women (P = 0.06). The prevalence of subtype C has increased over the HIV/AIDS epidemic, accounting for almost 60% of cases diagnosed in 2002. Intra-subtype genetic distances were smaller in subtype C than in subtype B, suggesting a more recent introduction of the former in the epidemic. Of patients under treatment, 60% had at least one antiretroviral drug resistance mutation, but no mutation was specifically associated with any HIV-1 subtype. Only one resistance mutation each was found in drug-naive patients with subtypes B and C.


CONCLUSIONS
Despite the fact that subtype C appeared in southern Brazil more recently than subtype B, it is now the predominant strain in Rio Grande. The epidemic spread of subtype C could be taking place in Brazil, and possibly in south America, a phenomenon similar to that seen in other countries where this subtype is now totally dominant.
Soares
Esmeralda A J M
EA
Laboratório de Virologia Molecular, Universidade Federal do Rio de Janeiro, Brazil.
Martínez
Ana M B
AM
Souza
Thatiana M
TM
Santos
André F A
AF
Da Hora
Vanusa
V
Silveira
Jussara
J
Bastos
Francisco I
FI
Tanuri
Amilcar
A
Soares
Marcelo A
MA
D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D024882:Drug Resistance, Viral / Q000235:genetics; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics
D019380:Anti-HIV Agents; D012367:RNA, Viral; D054303:HIV Reverse Transcriptase; D016333:HIV Protease