Molecular epidemiology of health care-associated transmission of hepatitis B and C viruses.

The term "molecular epidemiology" has been ascribed to a host of different activities that involve gene-sequence analysis. Some examples of molecular epidemiology include modeling exercises of phylogenetic trees to reconstruct epidemics; studies of the evolution of hepatitis C virus (HCV); rates of nucleotide substitution in the hepatitis B virus (HBV) surface (S) gene; variations in the core promoter/pre-core/core region of HBV genotype C from different sources; analysis of HBV surface antigen mutations; molecular clock analyses of the short-term evolution of HCV; and analyses of clades and surface antigen polymorphisms of HBV. However, for most epidemiologists molecular epidemiology of viral hepatitis usually refers to studies of gene-sequence homology in HBV or HCV recovered from people in the community or an institution that allows better characterization and assignment of related clusters of infection.