The unique HCV genotype distribution and the discovery of a novel subtype 6u among IDUs co‐infected with HIV‐1 in Yunnan, China

Abstract

The Yunnan province is the epicenter of HIV-1 epidemics in China and a center for drug trafficking to the other parts of the world. In six prefectures of this province, a total of 132 IDUs were recruited to determine the seroprevalence of HCV and HIV-1 and the positive rates were 93.94% and 68.18%, respectively (P <0.001). Co-infection with HCV and HIV-1 was found among 89 IDUs, of whom several HCV fragments were amplified and sequenced. Sequences of the HCV 5′NCR-C and NS5B region were determined from 82 IDUs. Phylogenetic analyses showed consistent genotyping among 80 IDUs. Among them HCV genotypes 1a, 1b, 3a, 3b, 6a, 6n, and a tentatively assigned novel 6u subtype were found in 1 (1.25%), 16 (20%), 19 (23.75%), 24 (30%), 4 (5%), 9 (11.25%) and 7 (8.75%) individuals, respectively. In two IDUs, genotyping results were discordant, suggesting mixed HCV infections or recombination. The proportion of patients with HCV 1b tended to decrease from the north to south and from the east to west in this province. Genotype 3 and 6 strains were more frequent in the southern prefectures. The novel subtype 6u strains were only detected in Dehong which borders Myanmar. Our findings showed a unique pattern of HCV genotype distribution, which is similar to that in the southeastern Asian countries but distinct from that among the general population in China. Routes of drug trafficking and the resulting high prevalence of HIV-1 infection may have contributed to this pattern of HCV genotype distribution.

Migration Patterns of Hepatitis C Virus in China Characterized for Five Major Subtypes Based on Samples from 411 Volunteer Blood Donors from 17 Provinces and Municipalities

“…In relation to a previous finding that 3b was detected more often among IDUs than among other people (31), we may speculate that its migration from the southwest to other regions was primarily by transmission via the IDU network. This is consistent with the known drug trafficking routes in Yunnan Province that link the Golden Triangle in Southeast Asian countries to China (17,27,31). This is also consistent with the finding that IDUs have played important roles in mediating the migration of HIV-1 across China (32).…”

“…This situation persisted to 2002, when we showed that 2a was the second most predominant subtype in cities in the northern part of the country. However, this was not the case in cities in the southwest and south, where the percentages of other HCV subtypes appeared to be high (15,17). In the present study, we also found that 2a represented the first major subtype among the volunteer blood donors in Shaanxi Province, accounting for 46.94% (23/49 donors), and the second major subtype among the donors in Xinjiang Province, accounting for 31.34% (21/67 donors).…”

“…Although six genotypes (genotypes 1 to 6), 18 subtypes (subtypes 1a, 1b, 1c, 2a, 2b, 2f, 3a, 3b, 4d, 5a, 6a, 6e, 6g, 6k, 6n, 6u, 6v, and 6w), and a number of unassigned variants have been detected in China, over 95% of these isolates belong to five major subtypes: 1b, 2a, 3a, 3b, and 6a (12)(13)(14)(15)(16)(17)(18)(19). Among them, subtype 1b is predominant nationwide, accounting for approximately 75% of all HCV infections, and this is followed by 2a.…”

“…However, in Guangdong Province, in the south, 6a is increasingly prevalent (51.5% among HCV-infected intravenous drug users [IDUs], 49.7% among HCV-infected volunteer blood donors, and 17.1% among HCV-infected patients with chronic liver disease) and has replaced 2a as the second predominant subtype (12)(13)(14). On the other hand, in Yunnan Province, in the southwest, genotype 3 is thriving and cocirculating with multiple different HCV lineages (17). Because the 6a sequences detected in Vietnam are more diverse than those characterized in China, we performed a Bayesian evolutionary analysis by sampling trees (BEAST) of the 6a sequences from both countries and found that the ancestral origin of 6a was in Vietnam and that it was subsequently introduced into China.…”

A Unique Pattern of HCV Genotype Distribution on Hainan Island in China Revealed by Evolutionary Analysis

“…In a series of recent studies, we have investigated the molecular epidemiology and evolutionary patterns of HCV in China, using samples obtained from patients, voluntary blood donors, and injection drug users (IDUs). However, the main focus of these studies was on individuals living in the mainland [13][14][15][16][17][18][19]. Although some patients from Hainan Island were included, the number was too small to represent [13].…”