Tracing the Origin and Northward Dissemination Dynamics of HIV-1 Subtype C in Brazil

Edson Delatorre,Keila Correia De Alcantara,Hector Romero,Atila Iamarino,Caio C M Freire,Ludimila Paula Vaz Cardoso,Mariza G Morgado,Paolo M De A Zanotto,Monick Lindenmayer Guimarães,Gonzalo Bello,José C Couto-Fernandez,Mariane Martins De Araújo Stefani

doi:10.1371/journal.pone.0074072

Edson Delatorre, Keila Correia De Alcantara + Show 10 more

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https://doi.org/10.1371/journal.pone.0074072

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Abstract

Previous studies indicate that the HIV-1 subtype C epidemic in southern Brazil was initiated by the introduction of a single founder strain probably originating from east Africa. However, the exact country of origin of such a founder strain as well as the origin of the subtype C viruses detected outside the Brazilian southern region remains unknown. HIV-1 subtype C pol sequences isolated in the southern, southeastern and central-western Brazilian regions (n = 209) were compared with a large number (n ~ 2,000) of subtype C pol sequences of African origin. Maximum-likelihood analyses revealed that most HIV-1 subtype C Brazilian sequences branched in a single monophyletic clade (CBR-I), nested within a larger monophyletic lineage characteristic of east Africa. Bayesian analyses indicate that the CBR-I clade most probably originated in Burundi and was introduced into the Paraná state (southern region) around the middle 1970s, after which it rapidly disseminated to neighboring regions. The states of Paraná and Santa Catarina have been the most important hubs of subtype C dissemination, and routine travel and spatial accessibility seems to have been the major driving forces of this process. Five additional introductions of HIV-1 subtype C strains probably originated in eastern (n = 2), southern (n = 2) and central (n = 1) African countries were detected in the Rio de Janeiro state (southeastern region). These results indicate a continuous influx of HIV-1 subtype C strains of African origin into Brazil and also unveil the existence of unrecognized transmission networks linking this country to east Africa.

Highlights

The global spread of the Human immunodeficiency virus type 1 (HIV-1) group M that took place in the second half of the twentieth century was associated to the random exportation of some viral strains out of the epicenter in Central Africa into previously unexposed human populations [1]
The first dataset, here called CAFR+BR (Table S1), was used to characterize the relationship between viruses sampled in Brazil (n = 209) with those circulating at 13 African countries (n = 1,961) with an estimated subtype C prevalence >5% [2]
The CEA clade has been previously associated to the east African region [26] and comprise 73% of sequences from east Africa, 9% of sequences from central Africa, and none of sequences from southern Africa included in this analysis

Summary

Introduction

The global spread of the Human immunodeficiency virus type 1 (HIV-1) group M that took place in the second half of the twentieth century was associated to the random exportation of some viral strains out of the epicenter in Central Africa into previously unexposed human populations [1]. The most prevalent HIV-1 group M variant worldwide is subtype C, which accounts for nearly half (48%) of all global infections [2]. This HIV-1 subtype is prevalent in several countries from southern, eastern and central Africa, India and Brazil. Initial estimates based on viral strains mostly sampled in Rio Grande do Sul propose that the founder event occurred around the early 1980s [4,8], but another study based on samples from several states traced back the origin of the Brazilian subtype C epidemic to 1960-1970 [5]

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