Molecular characterization of hepatitis C virus genotype 6 subtypes in Thai blood donors.
BACKGROUND
Hepatitis C virus (HCV) genotype is important for identifying effective antiviral therapy, evaluating pathogenic severity, and tracking transmission routes. In Thailand, HCV genotypes 3 and 1 are the most common. We have previously demonstrated an increasing appearance of genotype 6 in HCV infections in Thailand. However, only limited epidemiological data on genotype 6 in Thailand are available. This study aimed to characterize HCV genotype 6 among apparently healthy Thai blood donors.


METHODS
In total, 240 blood samples were collected from Phitsanulok Regional Blood Center, Phitsanulok, Thailand. RNA was reverse transcribed and amplified by the nested polymerase chain reaction. HCV genotyping was performed by direct sequencing and phylogenetic tree analysis of core sequences. Amino acid polymorphism of various subtypes of HCV genotype 6 was investigated.


RESULTS
Of the 240 samples, 192 were successfully sequenced for the core region and 84 were determined to be of HCV genotype 6 by phylogenetic analysis. The most prevalent HCV-6 subtypes were 6f > 6n > 6c > 6i. Amino acid sequences of the partial core region among these four subtypes differed by one to seven residues.


CONCLUSIONS
For HCV-6, the subtype 6f was commonly found in Thai blood donors. Comparison of core protein from various HCV-6 subtypes showed substantial polymorphisms, which may form the basis of future studies using samples from patients with clear HCV histories. This feature can be applied to therapies tailored to particular genotype variants.
Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand. Electronic address: sisaya@rocketmail.com.
Anchalee
A
Sistayanarain
Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand.
Suriya
S
Chaiwong
D058070:Asymptomatic Diseases; D001782:Blood Donors; D014644:Genetic Variation; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006526:Hepatitis C / Q000821:virology*; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013785:Thailand; D014758:Viral Core Proteins / Q000235:genetics
D012367:RNA, Viral; D014758:Viral Core Proteins
Blood donors; Genotype and subtype; Hepatitis C virus; Hepatitis C virus-6 subtypes