Trend of genetic links and clusters under different TN93 (Tamura and Nei 93) genetic distances.

Trend of genetic links and clusters under different TN93 (Tamura and Nei 93) genetic distances.</p

Multinomial logistic regression analysis comparing potential heterosexual and indeterminate men with pnMSM (n = 62).

Multinomial logistic regression analysis comparing potential heterosexual and indeterminate men with pnMSM (n = 62).</p

Classification of potential non-disclosed men who have sex with men (pnMSM) identified from clusters containing self-reported heterosexual men with HIV and related nodes in the genetic network using a genetic distance threshold of 0.75% substitutions/site.

Classification of potential non-disclosed men who have sex with men (pnMSM) identified from clusters containing self-reported heterosexual men with HIV and related nodes in the genetic network using a genetic distance threshold of 0.75% substitutions/site.</p

235 HIV-1 genetic clusters with 1085 singletons omitted.

235 HIV-1 genetic clusters with 1085 singletons omitted.</p

Comparison of characteristics between MSM and pnMSM.

Comparison of characteristics between MSM and pnMSM.</p

Cluster mapping of HIV-1 molecular network.

2-A is from self-reports; 2-B is from the analysis based on Fig 1 with pnMSM identified; 2-C shows 29 HIV-1 molecular clusters containing pnMSM where clusters surrounded by red loops indicate that they were comprised of self-reported heterosexual men, women, and MSM, while other clusters contained only MSM and self-reported heterosexual men. Singleton self-reported heterosexual men are omitted. A 143 HIV-1 molecular clusters containing self-reported heterosexual men and related nodes. B 143 HIV-1 molecular clusters containing self-reported heterosexual men and related nodes with potential non-disclosed men who have sex with men (pnMSM) identified (specified by dark purple and red dots). C 29 HIV-1 molecular clusters containing potential non-disclosed men who have sex with men (pnMSM).</p

Extent of mixture for samples from two sources.

BackgroundIn Guangxi province of China, there is a high prevalence of HIV in the general population and in men who have sex with men (MSM). However, there is still a low proportion of MSM among people living with HIV. This apparent contradiction could be due to the high proportion of potential non-disclosed MSM (pnMSM) among reported heterosexual men. We analyzed the genetic linkage of HIV specimens to address this problem aiming to (1) identify the optimal genetic distance threshold, which gave the highest number of genetic clusters, (2) document the proportion of potential non-disclosed MSM (pnMSM) among self-reported heterosexual men, and (3) determine predictors for pnMSM.MethodsPairwise genetic distances were computed among all samples. The genetic distance threshold giving the highest number of genetic clusters was identified. Self-reported heterosexual men were identified as belonging to the pnMSM group if they could be linked to any MSM in their cluster. Multinomial logistic regression was used to determine associated factors of being pnMSM.ResultsThe optimal genetic distance threshold was 0.75% substitutions/site. Among 896 self-reported heterosexual men, the frequency (percentage and 95% confidence interval) was 62 (6.9%, 5.2–8.6%) for pnMSM, 779 (86.9%, 84.7–89.1%) for indeterminate men and 55 (6.1%, 4.5–7.7%) for potential heterosexual men, respectively. Self-reported heterosexual men who were younger, single and more educated were more likely to be pnMSM.ConclusionBased on these findings, there is a need to pay more attention to sexually active, young and educated self-reported heterosexual men and provide them with voluntary counselling and testing and specific HIV prevention services.</div

GenBank accession numbers for random selected HIV sequences.

GenBank accession numbers for random selected HIV sequences.</p

Comparison of the number of pnMSM identified by linkage-based and cluster-based methods.

Comparison of the number of pnMSM identified by linkage-based and cluster-based methods.</p

Comparison of number and proportion of pnMSM identified by linkage-based and cluster-based methods at all genetic distance thresholds.

Comparison of number and proportion of pnMSM identified by linkage-based and cluster-based methods at all genetic distance thresholds.</p