Molecular network characteristics of HIV-1 CRF01_AE strain in Pengzhou,Sichuan Province
Objective To investigate the molecular network characteristics and related influencing factors of the HIV-1 CRF01_AE strain in Pengzhou,providing a reference for precise prevention and control.Methods Blood samples were collected from patients with newly reported HIV-1 infections in Pengzhou between March 2019 and August 2022.The pol gene regions of the samples were amplified using nested PCR and sequenced.A molecular network was constructed using genetic distance methods,and its characteristics were analyzed.Factors influencing network entry and was assessed through x2 tests and logistic regression analysis.Results In total,699 blood samples were collected,yielding 667 sequences,of which 335 were identified as CRF01_AE strains.The number of clusters peaked at a genetic distance of 0.70%,with 186 sequences entering the network,resulting in a network entry rate of 55.52%.These sequences formed 45 clusters,distributed across the 12 streets/towns in Pengzhou.Logistic regression analysis revealed that individuals aged ≥50 years(OR=1.57,95%CI:1.78-3.17)were more likely to enter the network compared to those aged 19-49.Individuals with primary education or below(OR=4.64,95%CI:1.48-14.59)were more likely to enter the network compared to those with high school education or above.Compared to LC Town,individuals from DJS Town(OR=0.22,95%CI:0.05-0.99),GH Town(OR=0.19,95%CI:0.04-0.80),and TP Street(OR=0.34,95%CI:0.16-0.76)were less likely to enter the network.There were 45 high-risk transmitters(24.19%,45/186)within the network,and they were predominantly male(68.89%,31/45),aged ≥50 years(93.33%,42/45),and exclusively involved in heterosexual transmission(100.00%,45/45).Three high-risk clusters comprising 26,22,and 19 individuals were identified.A total of 49.25%(33/67)of the individuals in these clusters reported a history of non-marital commercial heterosexual contact.Conclusions The transmission risk of HIV-1 CRF01_AE strains in Pengzhou is high and widespread.Continuous dynamic monitoring of CRF01_AE strains should be strengthened,and targeted prevention and control measures should be implemented in key areas of high-risk transmission.Interventions aimed at reducing commercial heterosexual contact are necessary to decrease the incidence of new infections.