The origin and spread of CRF85_BC, driven by heterosexual transmission among older people in Sichuan, China

Ling Su,Yi Feng,Dongbin Wei,Yiping Li,Linglin Zhang,Dan Yuan,Wenhong Lai,Hong Yang,Yali Zeng,Li Ye,Qiushi Wang,Shu Liang

doi:10.1186/s12879-020-05488-4

Ling Su, Yi Feng + Show 10 more

Open Access

https://doi.org/10.1186/s12879-020-05488-4

Copy DOI

Abstract

BackgroundCRF_BC recombinants, including CRF07_BC and CRF08_BC, were considered the predominant subtypes in China. Since the discovery of HIV-1 circulating recombinant form CRF 85_BC in Southwest China in 2016, this BC recombinant forms had been reported in different regions of China. However, the history and magnitude of CRF85_BC transmission were still to be investigated.MethodWe conducted the most recent molecular epidemiology of HIV-1 among newly reported HIV-1 infected patients in Sichuan in 2019 by sequencing and phylogenetic analysis of 1291 pol sequences. Then, we used maximum likelihood approach and the Bayesian Markov chain Monte Carlo (MCMC) sampling of pol sequences to reconstruct the phylogeographic and demographic dynamics of the CRF85_BC.ResultsHIV-1 CRF85_BC (68/1291, 5.27%) became the fourth most prevalent strain revealing a significant increase in local population. CRF85_BC were only found in heterosexually infected individuals and the majority of CRF85_BC (95.45%) were circulating among the people living with HIV aged 50 years and over (PLHIV50+), suggesting a unique prevalent pattern. The founder lineages of CRF85_BC were likely to have first emerged in Yunnan, a province of Southwest China bordering Sichuan, in the early 2000s. It then spread exponentially to various places (including Guangxi, Sichuan, et al) and became endemic around 2008.6 (2006.7–2010.2) in Sichuan.ConclusionTaken together, our findings on HIV-1 subtype CRF85_BC infections provided new insights into the spread of this virus and extended the understanding of the HIV epidemic in China.

Highlights

CRF_BC recombinants, including CRF07_BC and CRF08_BC, were considered the predominant subtypes in China
human immunodeficiency virus type 1 (HIV-1) CRF85_BC (68/1291, 5.27%) became the fourth most prevalent strain revealing a significant increase in local population
In early 1990s, HIV-1 Thai subtypes B′ and C were co-circulated among injection drug users (IDUs) [2] in Yunnan province in southwestern China bordering the ‘Golden Triangle’, leading to active inter-subtype recombination which generated CRF07_BC, CRF08_BC, and a large number of unique recombinant forms [3, 4]

Summary

Introduction

CRF_BC recombinants, including CRF07_BC and CRF08_BC, were considered the predominant subtypes in China. Since the discovery of HIV-1 circulating recombinant form CRF 85_BC in Southwest China in 2016, this BC recombinant forms had been reported in different regions of China. In early 1990s, HIV-1 Thai subtypes B′ and C were co-circulated among injection drug users (IDUs) [2] in Yunnan province in southwestern China bordering the ‘Golden Triangle’, leading to active inter-subtype recombination which generated CRF07_BC, CRF08_BC, and a large number of unique recombinant forms [3, 4]. Drug trafficking activities were considered to be responsible for the rapid spread of CRF07_BC and CRF08_BC across China [5]. From 1978, as commercial sex activity increased across the country [6], the proportion of newly reported HIV infections/acquired immune

Methods

Results

Discussion

Conclusion