title: Circulation of HIV-1 subtype A within the subtype C HIV-1 epidemic in Tamil Nadu, India.
abstract: The HIV-1 epidemic in India is caused mainly by subtype C viruses that are transmitted sexually and by injecting drug use. The state of Tamil Nadu in Southern India has an HIV-1 median prevalence of 16.8% among injecting drug users, 6.6% in men who have sex with men, and 4.6% in female sex workers. In the rural district of Namakkal, a prevalence >3% was detected among antenatal women. The goal of this study was to determine the HIV-1 molecular epidemiology in Tamil Nadu. Blood samples were collected from 40 high-risk HIV-seropositive individuals from Chennai and Namakkal. HIV-1 subtype was determined by envelope nucleotide sequencing. Among the samples studied, 85% were subtype C, however, a cluster of subtype A samples (12.5%) and one subtype E recombinant form CRF01_AE (close to the Thailand strains) were detected. The average genetic distance of subtype C samples from Chennai and Namakkal were 9.44 ± 0.77% and 11.8 ± 0.7%, respectively indicating an evolved epidemic. This pilot study confirmed that subtype C was predominant in these regions but an outbreak of subtype A was detected in Namakkal. These results stress the importance of periodic monitoring of circulating HIV-1 subtypes in South India.
authors.affiliation: Department of Experimental Medicine, Tamil Nadu Dr MGR Medical University, Chennai, Tamil Nadu, India. ragupathy.viswanath@fda.hhs.gov
authors.forename: Viswanath
authors.initials: V
authors.lastname: Ragupathy
authors.forename: Concepción
authors.initials: C
authors.lastname: Casado
authors.forename: Saramma Mini
authors.initials: SM
authors.lastname: Jacob
authors.forename: Narasappa Mathew
authors.initials: NM
authors.lastname: Samuel
authors.forename: C
authors.initials: C
authors.lastname: Lopez-Galindez
mesh_terms: D000293:Adolescent; D000328:Adult; D001769:Blood / Q000821:virology; D016000:Cluster Analysis; D058872:Epidemics; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D017720:Molecular Epidemiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D055815:Young Adult; D054299:env Gene Products, Human Immunodeficiency Virus / Q000235:genetics
chemical_list: D054299:env Gene Products, Human Immunodeficiency Virus