Molecular epidemiological characterization of human immunodeficiency virus-1 CRF01_AE strains in China

Abstract

Objective To understand the molecular epidemiological characterization of human immunodeficiency virus (HIV)-1 CRF01_AE strains in China. Methods Data were extracted by a systematic search in the databases combined with literature review. Data were then grouped according to the sites and risk groups for a Meta-analysis. Sequences of CRF01_AE pol genes from China were downloaded from Los Alamos database to build phylogenetic trees by means of FastTree2.1. The Bayes factor test was calculated by BEAST V1.6.2 package and Spread to explore spatial transmission links. Results Meta-analysis demonstrated that CRF01_AE strains accounted for more than 45.0% of all subtypes among men who have sex with men (MSM) in six areas of China. Among heterosexuals in eastern, northern, southwestern and south-central China, the proportions of CRF01_AE strains exceeded 30.0%. The strains were also prevalent among intravenous drug users in south-central regions, accounting for 57.3% (95%CI: 35.1%-79.6%), and were only detected among blood donors in south-central China (10.6%, 95%CI: 6.2%-14.9%). Seven distinct phylogenetic clusters of CRF01_AE strains which were transmitted independently were identified. Clusters 1, 3 and 5 were prevalent among heterosexuals, while clusters 2 and 6 were found primarily among MSM, and clusters 4 was detected chiefly among sexual contact people. Geographically, clusters 1, 2, 3, 4 and 5 were prevalent in southwestern areas. Clusters 1 and 7 were circulating in south-central areas. Clusters 2 and 6 were prevalent in northern areas, while clusters 2 and 4 were dominant in eastern regions and cluster 6 was prevalent in northeastern China. The Bayes factor test reveals the complexity of transmission links among eastern, south-central, southwestern, northern, and northeastern provinces. Conclusion CRF01_AE strains are prevalent in most high risk groups in multiple regions of China and the transmission between different regions is complicated. Key words: CRF01_AE strains; Epidemiology, molecular; Meta-analysis; Phylogenetic analysis; Bayes theorem