Genetic Characteristics of HIV-1 CRF12_BF First Identified in Guangdong Province, China

Characterization of an imported HIV-1 A1/A7/G recombinant in China

BACKGROUND

International migration has accelerated the HIV-1 spread across national borders, gradually reducing the restrictions on the geographical distribution of HIV-1 subtypes. Subtypes A and G are globally recognized as the third and sixth most dominant HIV-1 genotypes, mainly prevalent in Africa, but rarely detected in China. Here we reported an imported HIV-1 recombinant which was composed of sub-subtypes A1 and A7 of subtype A and subtype G genes in a Chinese female. This virus was the first HIV-1 recombinant including A7 genes reported in the world.

CASE PRESENTATION

The near full-length genome (NFLG) was obtained from the plasma sample of the female in an HIV-1 molecular epidemiological survey with 853 participants in China. Phylogenetic analyses showed that this NFLG sequence contains three A7 segments, four G segments and one A1 segment with seven breakpoints, and all these segments were closely related to HIV-1 references circulating in Africa. The evidence from epidemiological investigation indicated that this female participant had a more-than-two-years heterosexual contact history with a fixed partner from Nigeria, a country in west Africa, which further supported the results of phylogenetic analyses. By the Bayesian phylogenetic analyses, the times of most recent common ancestors (tMRCA) of the partial pol gene (nt2308-3284, A7 region) and full-length vpr-vpu plus partial env gene (nt5534-6858, G region) were estimated around 1989 and 1984, respectively.

CONCLUSIONS

In this study, by using the NFLG sequencing, we identified an imported HIV-1 A1/A7/G recombinant which was estimated to originate around 1980s in Africa and introduced into China with international migration. This study highlighted the complexity of the global HIV-1 epidemic, the necessity of using genome sequences to determine HIV-1 genotypes and the importance of real-time monitoring of HIV-1 infection among international migrants and travelers.

Tracing the origin of an imported HIV-1 sub-subtype A6 strain first identified in Zhejiang Province, China

Human migration and mobility have been identified as key drivers of HIV dissemination among nations, which increases the problem of genetic diversity. Here, we report the near full-length genome of HIV-1 A6 identified in a female patient in the remote mountain area of Lishui, Zhejiang Province, which is the first time A6 has been reported in China. The near full-length genome was amplified with two large amplicons of 5.5 kb and 3.7 kb, and then target PCR products were sequenced by Sanger sequencing. The A6 strain was confirmed by the Basic Local Alignment Search Tool (BLAST) and a maximum-likelihood (ML) phylogenetic tree. The time to the most recent common ancestor (tMRCA) was inferred to be 2004 (95% HPD interval: 2003-2006). The sequence harbored the L74I mutation, which is a key characteristic genetic marker of A6. Combining the above evidence with epidemiological investigations, this A6 strain was determined to be from Ukraine, which was supported by phylogenetic analysis. This study identified a foreign imported strain, indicating a trend of increasing complication in the HIV-1 epidemic in Zhejiang, China.

Genetic characteristics of HIV-1 CRF06_cpx and CRF56_cpx strains isolated in Guangzhou, China

Strains of the HIV-1 circulating recombinant forms (CRFs) 06_cpx and 56_cpx were identified for the first time in Guangzhou, China. The nearly full-length genome (NFLG) sequence was amplified, and the PCR products were sequenced by the Sanger method. The CRF06_cpx and CRF56_cpx strains were identified using the Basic Local Alignment Search Tool (BLAST) and confirmed by neighbour-joining (NJ) phylogenetic analysis. Additionally, these strains were found to contain transmitted drug resistance mutations that have little effect on first-line efavirenz (EFV)-based treatment. Genetic analysis of the detailed sequence data will provide more information on the HIV-1 epidemic in China.