Spatiotemporal and demographic history of the HIV-1 circulating recombinant form CRF31_BC in Brazil.

CRF31_BC is an HIVs-1 recombinant form very prevalent in the southernmost capital city of Brazil, Porto Alegre. Recent studies have been describing a growing number of cases of infection by CRF31_BC in other Brazilian cities and countries, suggesting a process of expansion of this strain. Aiming to describe the city of origin, dispersion routes and demographic history of CRF31_BC, this study analyzed all HIV-1 CRF31_BC and Brazilian BC mosaic publicly available sequences. CRF31_BC classification was performed by bootscanning and tree reconstruction methods. Bayesian phylogeographic and phylodynamic model approaches were used to reconstruct the spatiotemporal and demographic history of 95 sequences identified as CRF31_BC-like. Porto Alegre was estimated to be the origin and center of the dispersion of the CRF31_BC for most of the analyzed locations. However, some viral transitions independent from Porto Alegre were observed in other cities from the Rio Grande do Sul state and also in other Brazilian states. The estimated CRF31_BC epidemic growth rate was similar to subtype C and B in Brazil. Our findings suggest that CRF31_BC, although mostly prevalent in south region, is circulating nation-wide with some localities presenting autochthonous transmissions.

Fritsch HM ，Almeida SEM ，Pinto AR ，Gräf T ... -  《-》

Genetic characterization of HIV-1 BC recombinants and evolutionary history of the CRF31_BC in Southern Brazil.

Passaes CP ，Bello G ，Lorete RS ，Matos Almeida SE ，Junqueira DM ，Veloso VG ，Morgado MG ，Guimarães ML ... -  《-》

Short communication: Evidences of recent decline in the expansion rate of the HIV type 1 subtype C and CRF31_BC epidemics in southern Brazil.

Bello G ，Guimarães ML ，Passaes CP ，Matos Almeida SE ，Veloso VG ，Morgado MG ... -  《-》

Contribution of Epidemiological Predictors in Unraveling the Phylogeographic History of HIV-1 Subtype C in Brazil.

The phylogeographic history of the Brazilian HIV-1 subtype C (HIV-1C) epidemic is still unclear. Previous studies have mainly focused on the capital cities of Brazilian federal states, and the fact that HIV-1C infections increase at a higher rate than subtype B infections in Brazil calls for a better understanding of the process of spatial spread. A comprehensive sequence data set sampled across 22 Brazilian locations was assembled and analyzed. A Bayesian phylogeographic generalized linear model approach was used to reconstruct the spatiotemporal history of HIV-1C in Brazil, considering several potential explanatory predictors of the viral diffusion process. Analyses were performed on several subsampled data sets in order to mitigate potential sample biases. We reveal a central role for the city of Porto Alegre, the capital of the southernmost state, in the Brazilian HIV-1C epidemic (HIV-1C_BR), and the northward expansion of HIV-1C_BR could be linked to source populations with higher HIV-1 burdens and larger proportions of HIV-1C infections. The results presented here bring new insights to the continuing discussion about the HIV-1C epidemic in Brazil and raise an alternative hypothesis for its spatiotemporal history. The current work also highlights how sampling bias can confound phylogeographic analyses and demonstrates the importance of incorporating external information to protect against this. Subtype C is responsible for the largest HIV infection burden worldwide, but our understanding of its transmission dynamics remains incomplete. Brazil witnessed a relatively recent introduction of HIV-1C compared to HIV-1B, but it swiftly spread throughout the south, where it now circulates as the dominant variant. The northward spread has been comparatively slow, and HIV-1B still prevails in that region. While epidemiological data and viral genetic analyses have both independently shed light on the dynamics of spread in isolation, their combination has not yet been explored. Here, we complement publically available sequences and new genetic data from 13 cities with epidemiological data to reconstruct the history of HIV-1C spread in Brazil. The combined approach results in more robust reconstructions and can protect against sampling bias. We found evidence for an alternative view of the HIV-1C spatiotemporal history in Brazil that, contrary to previous explanations, integrates seamlessly with other observational data.

Gräf T ，Vrancken B ，Maletich Junqueira D ，de Medeiros RM ，Suchard MA ，Lemey P ，Esteves de Matos Almeida S ，Pinto AR ... -  《-》

Epidemiologic and evolutionary trends of HIV-1 CRF31_BC-related strains in southern Brazil.

Santos AF ，Schrago CG ，Martinez AM ，Mendoza-Sassi R ，Silveira J ，Sousa TM ，Lengruber RB ，Soares EA ，Sprinz E ，Soares MA ... -  《JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES》