Yongshui Fu

New trends of HCV infection in China revealed by genetic analysis of viral sequences determined from first-time volunteer blood donors

Summary.  Recently, we studied hepatitis C virus (HCV) sera‐prevalence among 559 890 first‐time volunteer blood donors in China. From randomly selected 450 anti‐HCV positive donors, we detected HCV RNA in 270 donors. In this study, we amplified HCV E1 and/or NS5B sequences from 236 of these donors followed by DNA sequencing and phylogenetic analysis. The results indicate new trends of HCV infection in China. The HCV genotype distribution differed according to the donors’ region of origin. Among donors from Guangdong province, we detected subtypes 6a, 1b, 3a, 3b, 2a, and 1a at frequencies of 49.7%, 31.0%, 7.6%, 5.5%, 4.1%, and 2.1%, respectively. Among donors from outside Guangdong, we detected 1b, 2a, 6a, 3b, 3a, 6e, and 6n at frequencies 57.1%, 13.2%, 11.0%, 9.9%, 4.4%, 2.2%, and 2.2%, respectively. Although we found no significant differences among regions in age or gender, subtype 6a was more common (P < 0.001) in donors from Guangdong than those from elsewhere, whilst subtypes 1b (P < 0.02) and 2a (P < 0.001) were more frequent outside Guangdong. Disregarding origins, the male/female ratio was higher for subtype 6a‐infected donors (P < 0.05) than for subtype 1b donors, whilst the mean age of subtype 2a donors was 8–10 years older (P < 0.05) than that for all other subtypes. Detailed phylogenetic analysis of our sequence data provides further insight into the transmission of HCV within China, and between China and other countries. The predominance of HCV 6a among blood donors in Guangdong is striking and mandates studies into risk factors for its acquisition.

HCV 6a Prevalence in Guangdong Province Had the Origin from Vietnam and Recent Dissemination to Other Regions of China: Phylogeographic Analyses

Background Recently in China, HCV 6a infection has shown a fast increase among patients and blood donors, possibly due to IDU linked transmission. Methodology/Findings We recruited 210 drug users in Shanwei city, Guangdong province. Among them, HCV RNA was detected in 150 (71.4%), both E1 and NS5B genes were sequenced in 136, and 6a genotyped in 70. Of the 6a sequences, most were grouped into three clusters while 23% represent emerging strains. For coalescent analysis, additional 6a sequences were determined among 21 blood donors from Vietnam, 22 donors from 12 provinces of China, and 36 IDUs from Liuzhou City in Guangxi Province. Phylogeographic analyses indicated that Vietnam could be the origin of 6a in China. The Guangxi Province, which borders Vietnam, could be the first region to accept 6a for circulation. Migration from Yunnan, which also borders Vietnam, might be equally important, but it was only detected among IDUs in limited regions. From Guangxi, 6a could have further spread to Guangdong, Yunnan, Hainan, and Hubei provinces. However, evidence showed that only in Guangdong has 6a become a local epidemic, making Guangdong the second source region to disseminate 6a to the other 12 provinces. With a rate of 2.737×10−3 (95% CI: 1.792×10−3 to 3.745×10−3), a Bayesian Skyline Plot was portrayed. It revealed an exponential 6a growth during 1994–1998, while before and after 1994–1998 slow 6a growths were maintained. Concurrently, 1994–1998 corresponded to a period when contaminated blood transfusion was common, which caused many people being infected with HIV and HCV, until the Chinese government outlawed the use of paid blood donations in 1998. Conclusions/Significance With an origin from Vietnam, 6a has become a local epidemic in Guangdong Province, where an increasing prevalence has subsequently led to 6a spread to many other regions of China.

The frequencies of human neutrophil alloantigens in the Chinese Han population of Guangzhou.

BACKGROUND: Antibodies against polymorphic structures on human neutrophil antigens (HNAs) play a role in alloimmune‐mediated neutropenia and are the leading cause of antibody‐mediated transfusion‐related acute lung injury (TRALI). This study aimed to determine the frequencies of HNAs in the major Han ethnic group living in Guangdong Province, Southern China.

A new HCV genotype 6 subtype designated 6v was confirmed with three complete genome sequences

BACKGROUND Although hepatitis C virus (HCV) genotype 6 is classified into 21 subtypes, 6a-6u, new variants continue to be identified. OBJECTIVE To characterize the full-length genomes of three novel HCV genotype 6 variants: KMN02, KM046 and KM181. STUDY DESIGN From sera of patients with HCV infection, the entire HCV genome was amplified by RT-PCR followed by direct DNA sequencing and phylogenetic analysis. RESULTS The sera contained HCV genomes of 9461, 9429, and 9461nt in length, and each harboured a single ORF of 9051nt. The genomes showed 95.3-98.1% nucleotide similarity to each other and 72.2-75.4% similarity to 23 genotype 6 reference sequences, which represent subtypes 6a-6u and unassigned variants km41 and gz52557. Phylogenetic analyses demonstrated that they were genotype 6, but were subtypically distinct. Based on the current criteria of HCV classification, they were designed to represent a new subtype, 6v. Analysis of E1 and NS5B region partial sequences revealed two additional related variants, CMBD-14 and CMBD-86 that had been previously reported in northern Thailand and sequences dropped into Genbank. CONCLUSION Three novel HCV genotype 6 variants were entirely sequenced and designated subtype 6v.

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

ABSTRACT We investigated the migration patterns of hepatitis C virus (HCV) in China. Partial E1 and/or NS5B sequences from 411 volunteer blood donors sampled in 17 provinces and municipalities located in five large regions, the north-northeast, northwest, southwest, central south, and southeast, were characterized. The sequences were classified into eight subtypes (1a, n = 3; 1b, n = 183; 2a, n = 83; 3a, n = 30; 3b, n = 44; 6a, n = 55; 6n, n = 10; 6v, n = 1) and a new subtype candidate. Bayesian evolutionary analysis by sampling trees of the E1 sequences of the five major subtypes revealed distinct migration patterns. Subtype 1b showed four groups: one is prevalent nationwide with possible origins in the north-northeast; two are locally epidemic in the central south and northwest, respectively, and have spread sporadically to other regions; and the fourth one is likely linked to the long-distance dispersion among intravenous drug users from the northwest. Subtype 2a showed two groups: the larger one was mainly restricted to the northwest and seemed to show a trend toward migration via the Silk Road; the smaller one was geographically mixed and may represent descendants of those that spread widely during the contaminated plasma campaign in the 1990s. Subtype 3a exhibited three well-separated geographic groups that may be epidemically unrelated: one showed origins in the northwest, one showed origins in the southwest, and the other showed origins in the central south. In contrast, subtype 3b had a mixture of geographic origins, suggesting migrations from the southwest to the northwest and sporadically to other regions. Structurally resembling the tree for subtype 3a, the tree for subtype 6a showed four groups that may indicate migrations from the central south to southeast, southwest, and northwest. Strikingly, no subtype 6a strain was identified in the north-northeast. IMPORTANCE With a population of greater than 1.3 billion and a territory of >9.6 million square kilometers, China has a total of 34 provinces and municipalities. In such a vast country, the epidemic history and migration trends of HCV are thought to be unique and complex but variable among regions and are unlikely to be represented by those observed in only one or at best a few provinces and municipalities. However, due to the difficulties in recruiting patients, all previous studies for this purpose have been based only on data from limited regions, and therefore, geographical biases were unavoidable. In this study, such biases were greatly reduced because we utilized samples collected from volunteer blood donors in 17 provinces and municipalities. To our knowledge, this is the first study in which the HCV isolates represented such a large portion of the country, and thus, the results should shed light on the current understanding of HCV molecular epidemiology.

Allelic distribution of HLA class I genes in the Tibetan ethnic population of China

Tibetans live in Qinghai‐Tibet Plateau rising about 4000 m a.s.l. in south‐west China. Archaeological evidences suggested that there have been humans living in Tibet at least 5000 years ago. However, Tibetan earlier history remains elusive. In the present study, allelic distribution of human leucocyte antigen (HLA)‐A, ‐B and ‐Cw in 158 unrelated Tibetan Chinese was investigated using sequencing‐based typing methods, and a total of 25 HLA‐A, 45 HLA‐B and 20 HLA‐Cw alleles were identified. A*24G1 (27.2%), B*51G1 (16.8%), Cw*04G1 (13.3%) and Cw*070201G1 (13.3%) are the most common HLA‐A, ‐B and ‐Cw alleles. The most frequently detected haplotypes were A*24G1‐B*51G1‐Cw*140201 (3.6%), A*24G1‐B*51G1 (6.8%), A*02G1‐Cw*070201G1 (6.5%) and B*51G1‐Cw*140201 (5.0%). Chi‐squared test suggested that all three loci fitted the Hardy–Weinberg expectations. No evidence for a departure from selective neutrality at the HLA‐A and ‐B loci was observed. However, significant departure of the observed homozygosity from the expected values was found for HLA‐Cw. Though the contemporary Tibetans inhabit the south‐west China, Neis genetic distance measure based on frequencies of HLA‐A, ‐B and ‐Cw indicated that Tibetans were closer to northern Han Chinese, Mongolian Chinese, Koreans and Japanese rather than to southern Han Chinese. The corresponding dendrogram constructed according to the neighbour‐joining method supported that Tibetans separated from southern Han and located in North‐East Asian cluster which included northern Han Chinese and Mongolian Chinese. These data were in good agreement with language classification and with a recent hypothesis that Tibetan might originate from northern China along Yellow river.

The seroprevalence of hepatitis C virus (HCV) among 559,890 first-time volunteer blood donors in China reflects regional heterogeneity in HCV prevalence and changes in blood donor recruitment models

BACKGROUND: A decrease in the prevalence of hepatitis C virus antibody (anti‐HCV) has been reported among voluntary blood donors in some regions of China. However, the prevalence of HCV among volunteer blood donors in other regions of China has not been reported. The aim of this study was to investigate the seroprevalence of HCV among 559,890 first‐time volunteer blood donors recruited during 2004 through 2007 at the Guangzhou Blood Center, China.

An expanded taxonomy of hepatitis C virus genotype 6: Characterization of 22 new full-length viral genomes.

We characterized the full-length genomes of 22 hepatitis C virus genotype 6 (HCV-6) isolates: 10 from Vietnam (classified into subtypes 6e, 6h, 6p, 6r, 6s, and 6u), one from China (confirmed as a new subtype 6xd), and 11 from the Lao PDR (representing a new subtype 6xe plus eight novel variants). With these 22 new genomes, HCV-6 now has a diverse and extended taxonomic structure, comprised of 28 assigned subtypes (denoted 6a-6xe) and 27 unassigned lineages, all of which have been represented by full-length genomes. Our phylogenetic analyses also included many partially-sequenced novel variants of HCV-6 from Lao PDR. This revealed that Lao HCV isolates are genetically very diverse and are phylogenetically distributed in multiple lineages within genotype 6. Our results suggest that HCV-6 has been maintained in Laos, a landlocked country, since the common ancestor of genotype 6 and indicates historical dispersal of HCV-6 across Southeast Asia.

Conservation in China of a novel group of HCV variants dating to six centuries ago.

UNLABELLED We characterized a novel group of HCV variants that are genetically related but distinct from each other belonging to genotype 6 (HCV-6). From 26 infected Austronesian-descended aborigines on Hainan Island, China, HCV sequences were determined followed by genetic analyses. Six nearly full-length genomes and 20 E1 sequences of HCV were obtained, which differ from each other and from all known HCV lineages by nucleotides above the intra-subtype level of 13%. Together with subtypes 6g and 6w, they constitute a phylogenetic group sharing a common ancestor dating from the end of the 12th century. CONCLUSION Our data indicate the maintenance of an isolated HCV-6 indigenous circulation on Hainan Island at least for six centuries.

A panel of 16 full-length HCV genomes was characterized in China belonging to genotypes 1–6 including subtype 2f and two novel genotype 6 variants

In this study, we characterized the full-length genomes of 16 HCV isolates obtained from patients in a single hospital in China using overlapping PCR followed by DNA sequencing. The obtained genomes are 9414-9628 nucleotides in length, and each genome contains a single ORF of 9021-9102 nucleotides. Nine genomes represent the common subtypes 1a, 1b, 2a, 2b, 3a, 3b, and 6a, while seven represent the infrequent lineages 1c, 2f, 4d, and 5a, and two novel genotype 6 variants. GZ51969 and GZ52540 are subtype 1b isolates belonging to two unique clusters designated A and B, which account for 29.5% and 59.5% of the 1b infections in China, respectively. ZS542 and GZ98799 represent the first two complete genomes of the provisionally assigned subtype 2f. ZS96 and ZS202 are novel genotype 6 variants that may qualify for two new subtypes. ZS17, ZS537, and ZS631 represent three alien subtypes, namely, 1c, 4d, and 5a, which were detected in China for the first time in this study and may have been recently introduced as a result of globalization. Taken together, these results confirmed a large variety of HCV taxonomic lineages in China through the sequencing of their full-length genomes. These lineages represent six genotypes, 11 subtypes, and two novel variants. They were characterized for achieving a better understanding of the HCV genetic variation patterns and for possible future research applications.