We examined the prevalence of serum anti-delta antibody among 769 intravenous drug abusers in Taiwan.
delta infection was found extremely common in the
HBsAg-positive carriers with
drug abuse, because 128 (85%) of 151 carriers were positive for anti-delta. However, most of antibody titers were low (less than 1:5,000). By molecular hybridization, delta
RNA genomes were detectable in only five (4%) of 128 asymptomatic carriers positive for anti-delta. The results suggested that most of them had previous, instead of ongoing,
delta infection. We also studied the
serum markers reflecting hepatitis B virus replication in these carriers and a control group.
Hepatitis B e antigen was positive in only 12 (10%) of 115 anti-delta positive carriers in contrast to 22 (23%) of 95 age- and sex-matched
HBsAg-positive, anti-delta negative volunteers donating blood (p less than 0.025). Furthermore, in contrast to the close association between
HBeAg and hepatitis B virus
DNA generally present in
HBsAg carriers (concordance in this series: 79%), among the 12
HBeAg-positive subjects of the delta infected group, only two, or 17%, had serum hepatitis B virus
DNA (p less than 0.003). Such suppressing effects did not require a simultaneous presence of the delta agent, as shown by the lack of delta
RNA genomes in the serum by sensitive assay. We conclude that although
delta superinfection is common in the asymptomatic
HBsAg carriers with
intravenous drug abuse in the nonendemic area of Taiwan, continuous delta activities are uncommon in them. In addition, the previous
delta infection probably exerts effective suppression on the hepatitis B virus replication in these
HBsAg carriers.