Estimating the origin of the HIV-1 CRF02_AG lineages circulating in Brazil
Date:
Poster presentation at XXV Brazilian Congress of Virology
Title: Estimating the origin of the HIV-1 CRF02_AG lineages circulating in Brazil
Authors: Delatorre, Edson, Velasco-de-Castro, Carlos Augusto, Pilotto, Jose Henrique, Bello, Gonzalo, & Morgado, Mariza Gonçalves
The HIV-1 CRF02_AG is one of the most prevalent circulating recombinant forms (CRF) in the world and is responsible for at least 8% of the HIV-1 infections worldwide. This CRF is distributed mainly in West Africa and, to a lesser extent, in the Middle East and North Africa. Due to the migrations from these endemic regions, CRF02_AG has been reported recently in countries where this recombinant is not native, including Brazil. In a previous study, including six CRF02_AG samples identified in Rio de Janeiro from 2004-2011, we found at least four introductions of this clade in Brazil, probably from Western African countries. As more CRF02_AG samples have been identified since then, in this study, we aimed to review the geographic origin and to date the introduction of some lineages circulating in Brazil using a larger dataset. A total of 20 Brazilian (18 from Rio de Janeiro and two from São Paulo) and 1,505 African HIV-1 CRF02_AG pol sequences were analyzed using Maximum Likelihood (ML) and Bayesian phylogeographic methods. The ML analysis showed that the 20 CRF02_AG Brazilian sequences were distributed in five different lineages. The Bayesian phylogeographic analysis of the Brazilian sequences and their most closely related African sequences (n = 212) placed the origin of all Brazilian lineages in West Africa, probably Ghana (lineages BR-I, BR-II and BR-III), Senegal (BR-IV) and Nigeria (BR-V). Lineages BR-I and BR-II comprise >1 sequence, all from the Rio de Janeiro state, and their dates of origin were estimated at 1985 (95% highest posterior density: 1979 – 1992). These results support the existence of at least five independent introductions of the CRF02_AG lineage from West Africa into Brazil and further indicate that at least two of these lineages have been disseminated in the Rio de Janeiro state for about 30 years.
