The Venezuelan Amerindians were, until recently, free of human immunodeficiency virus (HIV) infection. However, in 2007, HIV-1 infection was detected for the first time in the Warao Amerindian population living in the Eastern part of Venezuela, in the delta of the Orinoco river. The aim of this study was to analyze the genetic diversity of the HIV-1 circulating in this population.
The pol genomic region was sequenced for 16 HIV-1 isolates and for some of them, sequences from env, vif and nef genomic regions were obtained. All HIV-1 isolates were classified as subtype B, with exception of one that was classified as subtype C. The 15 subtype B isolates exhibited a high degree of genetic similarity and formed a highly supported monophyletic cluster in each genomic region analyzed. Evolutionary analyses of the pol genomic region indicated that the date of the most recent common ancestor of the Waraos subtype B clade dates back to the late 1990s.
At least two independent introductions of HIV-1 have occurred in the Warao Amerindians from Venezuela. The HIV-1 subtype B was successfully established and got disseminated in the community, while no evidence of local dissemination of the HIV-1 subtype C was detected in this study. These results warrant further surveys to evaluate the burden of this disease, which can be particularly devastating in this Amerindian population, with a high prevalence of tuberculosis, hepatitis B, among other infectious diseases, and with limited access to primary health care.
According to the UNAIDS Global 2010 report, Human immunodeficiency virus type 1 (HIV-1) infects around 33 million people worldwide . Estimates predict that around 1.7 million are infected in Latin America . In Venezuela, HIV-1 prevalence is estimated at approximately 0.7% . HIV-1 subtype B is the most prevalent subtype in the Americas and particularly in Venezuela , .
Amerindians, especially those living in remote communities in difficult access areas, are generally not infected with HIV. However, recent reports have documented HIV infection in some Amerindian communities in the Amazon basin –. The Warao Amerindians live in the Eastern part of Venezuela, were the Orinoco river forms a wide delta that branches off into hundreds of rivers and waterways that flow through 41.000 Km2 of swampy forests . High prevalence of hepatitis B virus (HBV) infection and tuberculosis is found among the Waraos , . Tuberculin PPD surveys have shown that approximately 60% of the population has been infected with tuberculosis (de Waard, JH, personal communication). In 2007, the Venezuelan Red Cross diagnosed for the first time HIV-1 infection in this population, reporting 5 cases. In this study we report the molecular characterization of the HIV-1 strains circulating within the Warao Amerindians two years after the first cases were detected.