Gräf Tiago, Machado Fritsch Hegger, de Medeiros Rúbia Marília, Maletich Junqueira Dennis, Esteves de Matos Almeida Sabrina, Pinto Aguinaldo Roberto
Laboratório de Imunologia Aplicada, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil Centro de Desenvolvimento Científico e Tecnológico, Fundação Estadual de Produção e Pesquisa em Saúde, Porto Alegre, RS, Brazil School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
Centro de Desenvolvimento Científico e Tecnológico, Fundação Estadual de Produção e Pesquisa em Saúde, Porto Alegre, RS, Brazil.
J Virol. 2016 Aug 26;90(18):8160-8. doi: 10.1128/JVI.00363-16. Print 2016 Sep 15.
The high incidence of AIDS cases and the dominance of HIV-1 subtype C infections are two features that distinguish the HIV-1 epidemic in the two southernmost Brazilian states (Rio Grande do Sul [RS] and Santa Catarina [SC]) from the epidemic in other parts of the country. Nevertheless, previous studies on HIV molecular epidemiology were conducted mainly in capital cities, and a more comprehensive understanding of factors driving this unique epidemic in Brazil is necessary. Blood samples were collected from individuals in 13 municipalities in the Brazilian southern region. HIV-1 env and pol genes were submitted to phylogenetic analyses for assignment of subtype, and viral population phylodynamics were reconstructed by applying Skygrid and logistic coalescent models in a Bayesian analysis. A high prevalence of subtype C was observed in all sampled locations; however, an increased frequency of recombinant strains was found in RS, with evidence for new circulating forms (CRFs). In the SC state, subtype B and C epidemics were associated with distinct exposure groups. Although logistic models estimated similar growth rates for HIV-1 subtype C (HIV-1C) and HIV-1B, a Skygrid plot reveals that the former epidemic has been expanding for a longer time. Our results highlight a consistent expansion of HIV-1C in south Brazil, and we also discuss how heterosexual and men who have sex with men (MSM) transmission chains might have impacted the current prevalence of HIV-1 subtypes in this region.
The AIDS epidemic in south Brazil is expanding rapidly, but the circumstances driving this condition are not well known. A high prevalence of HIV-1 subtype C was reported in the capital cities of this region, in contrast to the subtype B dominance in the rest of the country. This study sought to comparatively investigate the HIV-1 subtype B and C epidemics by sampling individuals from several cities in the two states with the highest AIDS incidences in Brazil. Our analyses showed distinct epidemic growth curves for the two epidemics, and we also found evidence suggesting that separate transmission chains may be impacting the viral phylodynamics and the emergence of new recombinant forms.
艾滋病病例的高发病率以及HIV-1 C亚型感染的主导地位是巴西最南端两个州（南里奥格兰德州[RS]和圣卡塔琳娜州[SC]）的HIV-1疫情有别于该国其他地区疫情的两个特征。然而，先前关于HIV分子流行病学的研究主要在首府城市开展，因此有必要更全面地了解推动巴西这一独特疫情的因素。从巴西南部地区13个市的个体中采集血样。对HIV-1 env和pol基因进行系统发育分析以确定亚型，并通过在贝叶斯分析中应用Skygrid和逻辑合并模型重建病毒群体系统发育动力学。在所有采样地点均观察到C亚型的高流行率；然而，在南里奥格兰德州发现重组毒株的频率增加，有证据表明存在新的流行形式（CRF）。在圣卡塔琳娜州，B亚型和C亚型疫情与不同的暴露群体相关。尽管逻辑模型估计HIV-1 C亚型（HIV-1C）和HIV-1B的增长率相似，但Skygrid图显示前者的疫情已经持续扩散更长时间。我们的结果突出了HIV-1C在巴西南部持续扩散的情况，并且我们还讨论了异性传播和男男性行为者（MSM）传播链可能如何影响该地区目前HIV-1亚型的流行情况。
巴西南部的艾滋病疫情正在迅速蔓延，但导致这种情况的具体情形尚不清楚。与该国其他地区以B亚型为主导不同，该地区首府城市报告了HIV-1 C亚型的高流行率。本研究试图通过对巴西艾滋病发病率最高的两个州的多个城市的个体进行采样，比较调查HIV-1 B亚型和C亚型疫情。我们的分析显示这两种疫情有不同的流行增长曲线，并且我们还发现证据表明不同的传播链可能正在影响病毒系统发育动力学以及新重组形式的出现。
