Hepatitis delta virus infection: a recently imported disease in New Zealand.

In a study of 565 hepatitis B antigen (HBsAg) positive persons from the Auckland region, antibody to the hepatitis delta virus was detected in 38. The largest number were in Samoans (61%) although the infection was present in some other Pacific Islanders. Among HBsAg positive healthy blood donors, antenatal patients and acute hepatitis patients between 3.8 and 4.8% were anti-delta positive; while 28% of chronic hepatitis patients were positive suggesting an association between this disease and delta infection. Some positive results were also found in sera from intravenous drug addicts. By contrast, anti-delta was uncommon in New Zealand born Maoris or Europeans. Delta infection can be detected in some Pacific Islanders, some European immigrants as well as intravenous drug addicts and has the potential to spread in an epidemic form to HBsAg carriers in the general community. Widespread vaccination against hepatitis B is recommended to eventually reduce the number of HBsAg carriers in New Zealand.