Recent high incidence of fulminant hepatitis in samara, Russia: Molecular analysis of prevailing hepatitis B and D virus strains

Until 1991, the Russian city of Samara was Largely isolated from other part s of Russia and the rest of the world. Very recently, Samara has seen an al arming increase in the incidence of hepatitis. The proportion of fulminant cases is unusually high. We wanted to assess the roles of hepatitis B virus (HBV) and hepatitis D virus (HDV) in acute viral hepatitis in this region by analyzing the prevailing strains of both and by determining their genoty pes and possible origin. Serum samples were screened for different serologi cal markers and by PCR followed by direct sequencing. Of the 94 HBV-positiv e samples (80% of which were acute infections), 37 (39%) were also HDV posi tive. Sixty-seven percent of the patients had anti-HCV antibodies, Twenty-f ive percent of all patients in the study had fulminant hepatitis. Statistic ally significant sex differences were found among fulminant cases. For HBV, the core promoter sequences of 62 strains were determined and all but one were found to be of genotype D. None of these had any deletions, Only one s train, from a patient with fulminant fatal hepatitis, showed multiple mutat ions. The pre-S2 region sequences of 31 HBV strains were also compared, Phy logenetically, these fell into two distinct groups within genotype D, sugge sting different origins. For HDV, part of the region encoding the delta-ant igen was sequenced from four strains. All proved to be of genotype I and we re similar to Far Eastern and Eastern European strains. The contribution of intravenous drug use to the sharp increase in viral hepatitis in this uniq ue setting is discussed.