Subtypes and transmission characteristics of HIV-1 in men who have sex with men in Lishui, Zhejiang

ObjectiveTo understand the subtypes and transmission characteristics of HIV-1 in men who have sex with men (MSM) in Lishui of Zhejiang province.

MethodsBlood samples were collected from the newly-diagnosed HIV-1 infected MSM who received no antiviral therapy in Lishui during 2015–2018, pol gene was amplified and sequenced, the gene subtypes and transmission characteristics were analyzed by phylogenetic tree construction, at last mutations on drug resistance was analyzed with online software CPR 6.0.

ResultsA total of 89 sequences were obtained successfully from 105 samples. The predominant subtypes were CRF01＿AE (49.4%, 44/89) and CRF07＿BC (37.1%, 33/89), others were B and CRF55_01B detected in 3 cases respectively and CRF08＿BC, CRF59_01B and URF(01_AE/BC) detected in 2 cases respectively. Eight transmission clusters were found, with the total clustered rate of 21.3% (19/89). Seven clusters of transmission were associated with the cases who lived in Liandu district (87.5%, 7/8). Three surveillance drug resistance mutations (M46I, V106A, K103N) were found respectively in three samples. The overall rate of transmitted drug resistance (TDR) was 3.4% (3/89).

ConclusionThere were 7 HIV-1 subtypes in Lishui, HIV-1 genetic diversity showed complexity trend, and the cases in Liandu district might play a central role in the spread of HIV. It is necessary to strengthen the surveillance and targeted intervention for the cases associated with major transmission clusters. However, the prevalence of TDR was at a low level.