Molecular characterization of human immunodeficiency virus type 1 and hepatitis C virus in paid blood donors and injection drug users in china

Abstract

China is facing a rapid upsurge in cases of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infection due to large numbers of paid blood donors (PBD), injection drug users (IDU), and sexual partners of infected individuals. In this report, a total of 236 HIV-1-positive blood samples were collected from PBD, IDU, and their sexual partners in the most severely affected provinces, such as Henan, Yunnan, Guangxi, and Xinjiang. PCR was used to amplify the p17 region of gag and the C2-V3 region of env of HIV-1 and the 5' noncoding region and a region of E1/E2 of HCV. Genetic characterization of viral sequences indicated that there are two major epidemics of HIV-1 and multiple HCV epidemics in China. The PBD and transfusion recipients in Henan harbored HIV-1 subtype B', which is similar to the virus found in Thailand, and HCV genotypes 1b and 2a, whereas the IDU in Yunnan, Guangxi, and Xinjiang carried HIV-1 circulating recombinant forms 07 and 08, which resemble those in India, and HCV genotypes 1b, 3a, and 3b. Our findings show that the epidemics of HIV-1 and HCV infection in China are the consequences of multiple introductions. The distinct distribution patterns of both the HIV-1 and HCV genotypes in the different high-risk groups are tightly linked to the mode of transmission rather than geographic proximity. These findings provide information relevant to antiviral therapy and vaccine development in China and should assist public health workers in implementing measures to reduce the further dissemination of these viruses in the world's most populous nation.

FIG. 1.

Map of China (A) and a detailed map of Henan (B). (A) The locations of Kunming, Yunnan (red dot); Nanning, Guangxi (blue dot); Urumqi and Yining, Xinjiang (green dots); Henan (purple); Beijing (orange star); and Hong Kong (open circle) are highlighted. Other provinces mentioned in the text are also indicated. (B) HIV-1-infected samples were collected from 15 of the 18 cities and are indicated by the black dots followed by the city names. HCV genotype 2a was largely restricted to the northeastern counties (light purple) within Henan, whereas genotype 1b was found in almost all the cities studied (purple plus light purple).

FIG. 2.

Neighbor-joining tree for HIV-1 p17 and C2-V3 sequences obtained from Yunnan, Guangxi, Xinjiang, Henan, and Beijing. Individual sequences are color coded, with the colors corresponding to the color of original cities on the map of China (Fig. 1). The horizontal branch was drawn in accordance with their relative genetic distances. A number of commonly used reference sequences for classifying HIV-1 genotypes were also included. HIV-1 found in Henan (purple) is subtype B′ and genetically linked with viruses found in Thailand, while those found in Yunnan (red), Guangxi (blue), and Xinjing (green) are CRF07 or -08, similar to subtype C found in India. HIV-1 found in Beijing (orange) is a mixture of multiple genotypes and recombinants. The recombinant strains are highlighted by the sequence name and the color of original cities.

FIG. 3.

Neighbor-joining tree for the HCV E1/E2 region sequences. The samples are color coded in the same way as for the HIV-1 analyses: red for Yunnan, blue for Guangxi, green for Xinjiang, and purple for Henan. Sequences from Hong Kong and from Guangdong are labeled by the black open and filled circles, respectively. The horizontal branch was drawn in accordance with their relative genetic distances. A number of commonly used reference sequences for classifying HCV genotypes were also included. HCV strains found in Yunnan (red), Guangxi (blue), and Xinjing (green) belong to genotype 1a, 1b, 3a, 3b, or 6, whereas those in Henan (purple) are genotype 1b or 2a.