Detection and clinical features of hepatitis C virus type 6 infections in blood donors from Hong Kong

Abstract

The genotype distribution of hepatitis C virus (HCV) was investigated in 212 viraemic blood donors from Hong Kong. A subset of the samples was investigated using three different genotyping assays to establish the accuracy of each in this population. These assays were restriction fragment length polymorphism (RFLP) of amplified 5' noncoding region (5'NCR) sequences, RFLP of the core region, and a serotyping assay using peptides from two antigenic regions of NS4. Genotypes detected in Hong Kong blood donors were 1a (6.2%), 1b (58.8%), 2a (1.4%), 2b (1.4%), 3a (1.9%), and 6a (27.0%). All genotyping assays produced concordant results. No evidence was obtained for the presence of type 6 group variants recently identified in Southeast Asia, other than type 6a. A serotyping assay based upon the detection of type-specific antibody to epitopes in NS4 produced similar results to the genotyping assays (98% concordance), but a reduced sensitivity (75%) compared with genotyping methods. Sequence variation in NS4 was not the cause of the reduced rate of detection of type 6 antibody in this population. Eighty-four percent donors infected with type 6a were male, compared to 75% donors infected with type 1b. The median alanine transaminase (ALT) level in type 6 infected donors was lower than in type 1b, (43.8 and 51.1 U/l, respectively) although these values were not statistically significant (P = 0.094). There was no significant difference between the ages of donors infected with types 1b and 6a. Risk factors for HCV infection in the blood donors included blood transfusion, intravenous drug abuse, and tattooing. A significantly greater number of donors infected with HCV-6a reported a history of drug abuse (66%) than donors infected with HCV-1b (7%).

Molecular Characterization of Human Immunodeficiency Virus Type 1 and Hepatitis C Virus in Paid Blood Donors and Injection Drug Users in China

“…Four samples obtained from the province of Guangdong (Fig. 3) were found to contain three genotype 6 sequences and one genotype 1b sequence, showing that genotype 6 is not confined to Hong Kong (21,26,41).…”

HCV infection in northeastern Brazil: unexpected high prevalence of genotype 3a and absence of African genotypes

“…In epidemiological analyses, genotype 1 largely predominates in the West, with genotype 3 usually found in association with intravenous drug abuse in Europe and the United States (7,14) . In Africa and the Middle East and Asia other genotypes such as 4 , 5 and 6 have been observed; other than genotype 4, which is associated with low response to antiviral treatment (11,16,19) , their responses to interferon are unknown.…”

The Epidemic Behavior of the Hepatitis C Virus

“…These differences most likely arise from the association of subtypes with specific transmission routes. This conclusion is strengthened by two observations: (i) types 4 and 6 can spread quickly if they enter efficient contact networks (36)(37)(38)(39) and (ii) in the absence of such networks, HCV type 1 in West Africa shows evidence of long-term endemic infection (7). However, the possibility of viral genetic variability in infectiousness among subtypes should not yet be discounted entirely (40).…”