INVESTIGATION OF HEPATITIS-B VIRUS TRANSMISSION IN A HEALTH-CARE SETTING - APPLICATION OF DIRECT-SEQUENCE ANALYSIS

An epidemiologically linked cluster of hepatitis B virus (HBV) infecti ons was investigated using HBV DNA amplification by a nested polymeras e chain reaction with primers complementary to the region around the i mmunodominant a determinant of the surface gene, part of the X and cor e genes, and precore region and direct nucleotide sequence analysis. T he cluster, in which 2 persons died of fulminant hepatitis, comprised 1 blood donor, 2 patients, and 2 health care workers. The Kimura two-p arameter method was used to compare variance among the cluster with th at in the control samples, which were collected from 7 patients infect ed with the same HBV subtype. Significantly less variation occurred wi thin the cluster than in the control group (unpaired t test, P < .05). In an unrooted phylogenetic tree analysis, the 5 study samples formed a cluster distinct from the controls. This direct molecular approach of analyzing conserved regions of the HBV genome differentiated betwee n viruses involved in HBV transmission events.