Investigation Of HIV Transmission Relationship Among Men Who Have Sex With Men By Molecular Trace Technology

ObjectiveThe subtypes of HIV gene among MSM are analyzed by molecular trace technology.Combined with epidemiological investigation,the transmission relationship and direction of HIV infection among MSM population will be inferred,the source of infection will be found and the transmission track will be traced.Combined with the risk factors of transmission,the risk of transmission will be identified to improve the precision of HIV prevention and control among this population.MethodsBased on the Sino-US AIDS prevention and control cooperation project,the molecular trace analysis of the samples collected by the Kunming Caiyun Sky Health Counseling Service Centre from March 2018 to August 2018 was carried out.Three gene fragments of gag,pol,env(1100bps,300bps,500bps in length)were amplified by nested PCR by extracting viral nucleic acid from serum samples,and the sequencing results were analyzed to determine the gene subtypes,and to identify the correlation of the samples.Then,according to the results of epidemiological investigation and ordinary sequencing,the samples with suspected transmission relationship were sequenced with high throughput while the env gene region was selected as the target fragment,and the sequencing results were analyzed.According to the gene similarity and quasi-population distribution of HIV strains in suspected transmission relationship samples,the transmission relationship and transmission direction between them were inferred.ResultsA total of 83 HIV infections were found in this survey,78 cases(9 cases were found to be infected through trace the contact person of HIV positives)and 5 cases were original positive,The average age is 28 years old(16～50 years old),mainly 16～35 years old,as for the education level,junior college and above accounts for the largest proportion(49.4%),the occupation is dominated by service industry(42.2%),and bisexuality accounts for 12%.83 infected samples were numbered,and their nucleic acids were extracted,and then amplified by nested PCR.Among them,63 sequences were obtained from gag gene region,73 from pol gene region,54 from env gene region,and 76 valid sequences were obtained totally,the amplification success rate was 91.57%(76/83).The main subtypes of HIV gene were CRF07_BC,CRF 01_AE,(73.68%)(56 1 76),URFs(18.42%(14 1 76),CRF01_AE/BC,CRF01_AE/C,CRF07_BC/CRF001_E,CRF01_AE/B were the main URFs.Based on the results of gag,pol,env gene subtypes and phylogenetic tree analysis,it is inferred that there may be a correlation between 10 groups of samples,including 4 groups of samples consistent with epidemiological survey:samples 24,25,Samples 52,53,Samples 64,65,and Samples 35,82.In addition,among the infected persons whose transmission relationship was not found in epidemiological survey,six groups may have correlation:sample 01,08,36,67,sample 18,33,sample 21,50,sample 11,12,sample 30,54 and sample 69,72.A total of 22 samples with correlation were successfully amplified,19 samples were successfully amplified,of which 01,52 and 64 were not successfully amplified,and the final samples amplified successfully included 8 groups of relevant samples.All 19 successfully amplified samples were sequenced successfully by high throughput.More than 600000 original sequences were obtained.The effective sequences of 18871～52144(average 33745)were obtained.After eliminating the repetitive sequence,the unique quasi-population 101～619(average 437)was obtained from the final 19 samples.The dominant quasispecies arranged in the top 20 were selected and the phylogenetic tree was constructed.The results showed that the quasispecies sequences of 4 out of the 8 groups of correlation samples were aggregated into clusters,the reliability was more than 99%,and there was a high correlation,including samples 11 and 12,24 and 25,21 and 50,18 and 33.Among them,there is a parallel relationship between two groups of samples,which is sample 11 and 12,sample 24 and 25,indicating that there is a direct transmission relationship between the samples.The other four groups of samples,in which sample 69 and 72 quasispecies sequences were aggregated in one place,but the reliability was low(26%),while the other three groups of samples(08,36,67,30,35,53,54,65,82)quasispecies were separated into clusters,which basically ruled out the possibility of transmission.Four groups of highly correlated samples combined with epidemiological investigation found that temporary sex plays an important role in the process of transmission,and the process of HIV transmission among MSM is far more complex than the clues provided at present.In addition,the reason why some trace survey was not successful include HIV positives were unwilling to mobilize,could not contact each other and wanted to mobilize but worried it may expose their HIV infection status.Conclusion1.The genotypic composition of HIV infected MSM is complex,and the main genotypes are CRF07_BC,CRF01_AE and URFs.2.The analysis of transmission relationship through molecular trace technology showed the correlation by epidemiological survey was not high,suggesting that the transmission process of HIV among MSM was far more complex than the clues provided,and epidemiological investigation and laboratory analysis should be combined to better understand the transmission track of MSM,which has scientific and practical value in improving HIV precise prevention and control strategies.3.Molecular trace analysis found that those who denied temporary sexy infection were eventually spread or have a high degree of correlation.,it is suggested that polysexual partners and temporary behavior occur frequently among MSM.4.The positive numbers of this partner tracing is low,it is suggested that a variety of methods should be used to excavate,expand the scope and quantity of excavated population,and improve the quality of trace investigation.