MIXED GENOTYPES INFECTION WITH HEPATITIS-D VIRUS

Heterogeneity of hepatitis C viral (HCV) genomes results in escape fro m immune clearance. Super-infection or mixed infection of different ge notypes of HCV are seen commonly in humans. Hepatitis D virus (HDV) is classified into 3 genotypes. This study was planned to investigate if mixed genotypes infection of HDV occurs in humans. HDV genotyping bas ed on restriction fragment length polymorphism (RFLP) was used to scre en 60-99 HDV clones from each case of 7 prostitutes and 11 patients. M ixed infections were diagnosed by the finding of two or more different RFLP patterns in a case and were confirmed by sequencing. Five prosti tutes had mixed infections of genotypes IIa and IIb HDV, while only 2 patients had mixed infections of genotypes I and II HDV(P< 0.05). The heterogeneity in nucleotide sequence was generally below 2% among HDV quasi-species from the same subject, while the heterogeneity was 27.7% between genotypes I and II HDV, and 22.8% between genotypes IIa and I Ib HDV from a subject with mixed infection. Multiple HDV clones from t he spouses of the 2 index cases were also analyzed. One spouse had mix ed infection and the other did not, corresponding to the index cases. In cases with mixed genotypes infections, the prevalence of the minor strain was less than 10% of the total colony population analyzed. J. M ed. Virol. 57:64-67, 1999. (C) 1999 Wiley-Liss, Inc.