HIV type 1 subtypes in Guangxi Province, China, 1996.

Abstract

81 HIV-1 INFECTION WAS FIRST DOCUMENTED IN China in 1985; by 1997, the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimated that there were 200,000 to 400,000 HIV-infected persons living in China among a population of 1.2 billion.3 To date, most infections have occurred among injection drug users (IDUs), primarily in ethnic minority communities in Yunnan, a southwestern province bordering Myanmar (Burma), Laos, and Vietnam. This province can be seen as an extension of the a Golden Triangleo region of northern Thailand, Myanmar, and Laos, one of the world’ s foremost opiumand heroin-producing areas. In recent years, HIV-1 transmission has extended to new areas of China, and sexual transmission has increased in importance. The HIV-1 epidemic among IDUs in Yunnan province was primarily due to env subtype B strains, both typical North American/European-like subtype B strains and strains that clustered on phylogenetic analyses with subtype B strains found among IDUs in Thailand, termed B 9 (formerly Thai B).9±11 Subsequently, subtype C viruses were identified among IDUs in Yunnan. More recently, both subtype C and subtype E strains have been reported among geographically separate groups of IDUs in Guangxi province.13 There also appear to have been multiple other introductions of subtype E strains in China10,14 and subtype A has also been identified.10 We investigated the molecular epidemiology of HIV-1 in Guangxi, a southwestern Chinese province bordering Yunnan, Guizhou, Hunan, and Guangdong provinces and northern Vietnam. Guangxi, a mountainous, subtropical area, has a population of approximately 45 million, of whom about a third are ethnic minorities. From April through July 1996, blood samples were collected from HIV-seropositive persons identified at blood donation centers, drug treatment centers, and other testing locations. Specimens were obtained from 44 persons: 25 commercial blood donors (mean age, 24.5 years [range, 18±36]; 21 male and 4 female), 16 IDUs from drug treatment centers (mean age, 22.8 years [range, 16±38]; 14 male and 2 female), 2 men (aged 29 and 35 years) who had traveled to Thailand and reported sex with female sex workers, and 1 female (aged 36) who did not inject drugs and whose husband had AIDS. Fifteen of the 16 IDUs were identified in Pingxiang, a city near the border with Vietnam; the other IDU was located in Nanning, in central Guangxi. The other 28 persons were identified from throughout the province. All specimens were HIV-1 positive by enzyme immunoassay (EIA) and Western blot when tested at the Guangxi AIDS Surveillance and Testing Center, Nanning. Unlinked serum specimens were transferred to Nonthaburi, Thailand, and then to Atlanta, Georgia for further characterization. In Thailand, specimens were tested with 14-amino acid V3loop peptide enzyme immunoassays (PEIAs) highly specific for subtypes B 9 and E from Thailand.15±17 Serum specimens were later sent to the Centers for Disease Control and Prevention (Atlanta, GA) for genetic characterization. RNA was prepared with a blood kit from Qiagen (Chatsworth, CA). RNA from each sample was reverse transcribed (primer JH35R) and subsequently amplified by nested PCR (outer primers JH44F/JH35R and inner primers JH33F/JH48R). The 525-bp nested C2±V4 PCR product encompasses the V3 loop. The sequences of these HIV-1 group M env (gp120) gene-based degenerate/inosine primers with coordinates on HIV-MNCG sequence (in parentheses) are as follows: