| Objectives:To better understand the characteristics of HIV-1 transmission characteristics and drug resistance in the border area of Lincang City,Yunnan Province,a molecular epidemiological survey of HIV-1 was conducted in Gengma County,Zhenkang County and Cangyuan County of Lincang City in 2021.This study analyzes the distribution characteristics of HIV-1 genotypes and the prevalence of pretreatment drug resistance in the border areas of Lincang City,and further explored the risk of HIV transmission,which provided basis for targeted improvement of prevention and treatment strategies.Methods:Blood samples from newly reported HIV-1 infected individuals were collected in2021 in the border area of Lincang City,Yunnan Province.The samples were amplified and sequenced for gag,pol and env gene regions.Demographic information of the samples was collected and collated through questionnaires and the Integrated AIDS Control Information System.Sequences successfully sequenced were assembled and edited using Sequencher 5.1 and Bio-Edit 7.0 software,and phylogenetic trees were constructed using MEGA 11.0 to determine genotyping.Using the pol region gene sequences,drug resistance mutations and resistance levels were analysed in the Stanford Drug Resistance Database.Epidata 3.1 was used to build the database,as well as data from the entry questionnaire.Results:1.A total of 238 blood samples were obtained from newly reported HIV-1 infections in Zhenkang County,Cangyuan County,and Gengma County,Lingcang City in 2021.A total of 138 sequences in the gag region,170 sequences in the pol region and 164 sequences in the env region were obtained by amplification and sequencing.Combining the typing results of three gene regions,174 sequences were obtained for the final genotyping.2.Among the 174 participants genotyped,the average age was 41.1±12.8 years old,91.4% were Chinese,8.6% were Burmese;78.7% were registered residence in Lincang City.The study population was predominantly male(67.2%),Wa(40.2%),primary school(49.4%),farmers(90.8%),married or with a spouse(41.4%),domiciled in Gengma County(55.7%)and heterosexual transmission(96.6%).3.Of the 174 samples successfully genotyped,11 genotypes were obtained.CRF08＿BC(56.9%)was the predominant strain,followed by URFs(14.4%,25/174)and CRF01＿AE(10.9%,19/174),CRF07＿BC(8.0%,14/174),Subtype C(4.0%,7/174),CRF111＿01C(1.7%,3/174),CRF55＿01B(1.1%,2/174),CRF85＿BC(1.1%,2/174),CRF65＿cpx(1.1%,2/174),CRF118＿BC(0.6%,1/174)and Subtype B(0.6%,1/174).4.There were statistical differences in the distribution of HIV-1 genotypes among populations of different nationalities and different transmission routes.The predominant genotype in Chinese nationals was CRF08＿BC(60.4%,96/159),while the predominant subtype in Myanmar nationals was URFs(40.0%,6/15).The predominant strains for heterosexual contact,homosexual contact and intravenous drug use were CRF08＿BC(58.3%,98/168),CRF07＿BC(66.7%,2/3)and URFs(100.0%,3/3),respectively.5.By constructing the HIV-1 molecular network,60 broken sequences entered the network,with an entry rate of 35.30%(60/170).6.There were differences in the entry rates in different counties,with Zhenkang County having a lower entry rate(12.5%,2/16)than Gengma County(42.1%,40/95)and Canyuan County(30.5%,18/59).Analysed separately by county,those aged 41 and over in Gengma County were more likely to be in the network,while Canyuan County was more likely to be in the network among those aged 40 and under.When classifed by reporting counties of both end of links,there were differences in the composition of the types of connections in different counties.Canyuan and Gengma counties were mainly dominated by links within their own counties,accounting for 93.8%(15/16)and 79.4%(50/63)of the reports respectively,while Zhenkang County was dominated by crosscounty links,with 92.3%(12/13)of Zhenkang-Gengma links.7.Of the 170 sequences with pol sequences,41.8%(71/170)had drug resistance mutations(DRMs),of which 38.2%(65/170)had DRMs to NNRTIs,2.9%(5/170)had DRMs to NRTIs and 2.4%(4/170)had DRMs to PIs.Among them,the resistance loci V106 I,E138A/G/K/R,V179D/VD/E/T,K43 T and F53 FL were statistically different in genotype distribution.Drug resistance analysis revealed that 17 cases carried drug resistant strains,with a resistance rate of 10.0%(17/170).The prevalence of pretreatment drug resistance(PDR)to NNRTIs and NRTIs was 9.4%(16/170)and 0.6%(1/170),respectively.Conclusions:1.A variety of HIV-1 genotypes are found in this study,of which CRF08＿BC,URFs and CRF01＿AE are the predominant strains.2.In the HIV-1 molecular network,there are statistical differences in entry rates across counties.Most of the links in Gengma and Canyuan counties occured mainly within their own counties,however,most of the links in Zhenkang County are across the county.3.The diverse DRMs exist in the HIV-1-infected population in the border area of Lincang City.Some DRMs differe in the different genotypes.The molecular network analysis suggests the presence of DRMs transmission.The overall prevalence of PDR resistance has shown an increasing trend in this area.The prevalence of pre-treatment resistance is close to the threshold for initiating a public health response. |
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