Genetic analysis of wild-type hepatitis A virus strains

Objective To clarify the distribution of hepatitis A virus (HAV) genotype i n geographical regions of China. Methods Seventeen representative HAV strains were isolated from the stool o r serum of hepatitis A patients in different geographical regions. Viral RN A was recovered from stool or serum by proteinase K digestion and phenol-ch loroform extraction, followed by ethanol precipitation prior to reverse tra nscription and polymerase chain reaction (RT-PCR) amplification. The nucleo tide sequences of VP1/2A junction region were tested by using a direct sequ encing technique. Results A pairwise comparison of sequences within 168 bases at the VP1/2A j unction revealed that all the sequences clustered within genotype I. About 53% of strains clustered in genotype I B, with less than 6% variability; wh ile the others clustered in genotype IA, with less than 5.3% variability. S equence 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 geno type IA or I B. Epidemiologically related strains may be identical or close ly related in sequence.