Molecular epidemiology of HIV in newly diagnosed individuals from 2005 to 2007 in Argentina.

PANDO MA; VIGNOLES M; ALFIE L; AVILA MM; SALOMON H; GOMEZ CARRILLO M

Mexico

Conferencia; XVII International AIDS Conference; 2008

IAS

Background: Several studies performed in Argentina showed that HIV-1 subtype distribution is strongly associated with different transmission routes. A high prevalence of BF recombinants has been associated with vertical transmission since 1984, reflecting the spread of these variants into the heterosexual population. Nevertheless B subtype was highly predominant (almost 90% in some studies) in men who have sex with men (MSM).Several studies performed in Argentina showed that HIV-1 subtype distribution is strongly associated with different transmission routes. A high prevalence of BF recombinants has been associated with vertical transmission since 1984, reflecting the spread of these variants into the heterosexual population. Nevertheless B subtype was highly predominant (almost 90% in some studies) in men who have sex with men (MSM). Objective: to describe the evolution of HIV subtypes in different risk groups from 2005 to 2007 in Buenos Aires, Argentina.to describe the evolution of HIV subtypes in different risk groups from 2005 to 2007 in Buenos Aires, Argentina. Methods: HIV-1 subtypes were characterized in a total 205 newly diagnosed individuals over the period 2005-2007. 110 were adults [86 MSM, 12 Sex Workers (SWs) and 12 Drug Users (DUs)] and 95 were children born to infected mothers. Subtype characterization was performed by using nucleotide sequences obtained from RT-PCR products of pol gene. Phylogenetic trees were constructed by Neighbor-Joining.HIV-1 subtypes were characterized in a total 205 newly diagnosed individuals over the period 2005-2007. 110 were adults [86 MSM, 12 Sex Workers (SWs) and 12 Drug Users (DUs)] and 95 were children born to infected mothers. Subtype characterization was performed by using nucleotide sequences obtained from RT-PCR products of pol gene. Phylogenetic trees were constructed by Neighbor-Joining. Results: Overall, the subtype distribution in adults was 71.8% B subtype, 27.2% BF recombinants and 1% C subtype. Regarding the route of infection, B subtype was more prevalent in MSMs (76%) and SWs (67%). In DUs the prevalence of BF recombinants was 50%. Only one non B-non BF (C subtype) was found in a MSM patient. In this adult population, 83% of the UDs and 75% of the SWs were males, however no relationship between gender and subtype distribution was found. In the pediatric population, 21 % was found to be infected with B subtype viruses while 79% with BF recombinants.Overall, the subtype distribution in adults was 71.8% B subtype, 27.2% BF recombinants and 1% C subtype. Regarding the route of infection, B subtype was more prevalent in MSMs (76%) and SWs (67%). In DUs the prevalence of BF recombinants was 50%. Only one non B-non BF (C subtype) was found in a MSM patient. In this adult population, 83% of the UDs and 75% of the SWs were males, however no relationship between gender and subtype distribution was found. In the pediatric population, 21 % was found to be infected with B subtype viruses while 79% with BF recombinants. Conclusions: The evidence of the high prevalence of BF recombinants in the pediatric population reflects that two different epidemics continue in Argentina. However, the higher proportion of non-B subtypes founded in MSM and the B subtype prevalence found in UDs and SWs evidences the dynamic of the epidemic in the region. Phylogenetic relationships among variants are under analysis.The evidence of the high prevalence of BF recombinants in the pediatric population reflects that two different epidemics continue in Argentina. However, the higher proportion of non-B subtypes founded in MSM and the B subtype prevalence found in UDs and SWs evidences the dynamic of the epidemic in the region. Phylogenetic relationships among variants are under analysis.