Heterosexual transmission of novel CRF01_AE and subtype B recombinant forms of HIV type 1 in northern Thailand

Predictors for recombinant HIV infection in a Thai cohort

Recombinant human immunodeficiency virus (HIV) infection was associated with exchange of sex for money, ≥1 sex partner within the prior 6 months, and decline in CD4 cell count in this Thai cohort study. These findings suggest that recombinant HIV infection may have implications for HIV disease progression, safer sex practices, and vaccine development.

Non-B HIV type 1 subtypes among men who have sex with men in Rome, Italy

An increase in the circulation of HIV-1 non-B subtypes has been observed in recent years in Western European countries. Due to the lack of data on the circulation of HIV-1 non-B subtypes among European HIV-1-infected men who have sex with men (MSM), a biomolecular study was conducted in Rome, Italy. HIV-1 partial pol gene sequences from 111 MSM individuals (76 drug naive and 35 drug experienced) were collected during the years 2004-2006. All these sequences were analyzed using the REGA HIV-1 Subtyping Tool, and aligned using CLUSTAL X followed by manual editing using the Bioedit software. A BLAST search for non-B subtype sequences was also performed. Twenty-six (23.4%) MSM were not Italians. Eight individuals (7.2%) were diagnosed as HIV infected before 1991, 20 (18.0%) between 1991 and 1999, and 83 (74.8%) from 2000 to 2006. Fifteen (15/111, 13.5%) individuals were infected with the non-B subtype. The percentage of infection with HIV-1 non-B subtypes was 8.2% (7/85) among Italian MSM and 30.8% (8/26) among the non-Italians (OR = 4.95 95% IC: 1.40-17.87). Individuals infected with the non-B subtype were significantly younger than those infected with the HIV-1 B subtype (28 years vs. 34 years, p = 0.003). The CRFs were more prevalent (8.1%) than pure subtypes (5.4%), which were distributed as follows: subtype C (2.6%), subtype A1 (1.7%), and subtype F1 (0.9%). Major mutations conferring resistance to antiretroviral drugs (ARV) were not found among HIV-1 non-B subtype drug-naive patients but were found in two ARV-experienced individuals. The data show that viral diversity is likely increasing in a population group that had been previously characterized by the circulation of HIV-1 subtype B.

The HIV type 1 epidemic in Bulgaria involves multiple subtypes and is sustained by continuous viral inflow from West and East European countries

Little is known about the HIV-1 epidemic in Balkan countries. To fill the gap, we investigated the viral genetic diversity in Bulgaria, by sequencing and phylogenetic characterization of 86 plasma samples collected between 2002 and 2006 from seropositive individuals diagnosed within 1986-2006. Analysis of pol gene sequences assigned 51% of the samples to HIV-1 subtype B and 27% to subtype A1. HIV-1 subtype C, F, G, H, and a few putative recombinant forms were also found. Phylogenetic and molecular clock analysis showed a continuous exchange of subtype A and B between Bulgaria and Western as well as other Eastern European countries. At least three separate introductions of HIV-1 subtype A and four of HIV-1 subtype B have occurred within the past 25 years in Bulgaria. The central geographic location of Bulgaria, the substantial genetic heterogeneity of the epidemic with multiple subtypes, and the significant viral flow observed to and from the Balkan countries have the potential to modify the current HIV-1 epidemiological structure in Europe and highlight the importance of more extensive and continuous monitoring of the epidemic in the Balkans.

Clinical impact of HIV-1 subtype: are there important differences?

The enormous genetic diversity of HIV-1 is a major challenge to vaccine development and may have important clinical consequences. HIV-1 group M predominates globally, with nine subtypes, several sub-subtypes and over 30 circulating recombinant forms that may exhibit differences with respect to transmissibility, pathogenicity and development of antiretroviral resistance. Subtype D appears to be more virulent than other subtypes, in particular subtype A. Subtype C may be less virulent and more transmissible, although the evidence for this is inconclusive. All group M non-B subtypes appear to be equally susceptible to combination antiretroviral therapy, but development of resistance mutations may vary significantly between subtypes. Further research into the clinical implications of HIV-1 diversity is crucial for effective HIV-1 prevention and treatment.