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Genetic analysis of wild-type hepatitis A virus strains
1Zhejiang Academy of Medical Sciences, 60 Tian Mu Shan Road, Hangzhou 310013, China.
Objective:
To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China.
Methods:
Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions. Viral RNA was recovered from stool or serum by proteinase K digestion and phenol-chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT-PCR) amplification. The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique.
Results:
A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype I. About 53% of strains clustered in genotype I B, with less than 6% variability; while the others clustered in genotype I A, with less than 5.3% variability. Sequence homology between genotype I A and I B varied from 88.7% to 92.3%.
Conclusion:
Epidemic or sporadic HAV strains in China may belong to HAV genotype I A or I B. Epidemiologically related strains may be identical or closely related in sequence.