Hepatitis delta virus: molecular biology, pathogenesis and immunology

Hepatitis delta virus (HDV) is a unique infectious agent which causes severe liver disease in those infected with its helper virus, hepatitis B virus. No effective antiviral therapy for HDV exists. This review covers recent advances in the molecular biology, pathogenesis and immunology of HDV, with an emphasis on potential targets for the development of successful antiviral agents.

Injecting behaviours and prevalence of hepatitis B, C and D markers in New Zealand injecting drug user populations

AIM

To determine the seroprevalence of hepatitis C virus (HCV), hepatitis B virus (HBV) & hepatitis D virus (HDV) markers of infection among injecting drug user populations in New Zealand and to examine the relationship between demographic features, risk behaviours and infection.

METHODS

A total of 323 current injecting drug users completed a questionnaire that explored their needle and syringe using behaviours. Information was collected on injection pattern, sharing behaviours and methods of cleaning needles and syringes. Two hundred and forty-one respondents gave blood samples which were tested for hepatitis B, C and D markers.

RESULTS

Over half the respondents (59%) were male and 41% were female. Most (89%) identified as European. Sixty-four percent were anti-HCV positive. The likelihood of infection increased with age and duration of injecting. Forty-one percent (33/81) of those aged 25 or under, sixty-four percent (45/70) of those aged 26-30 and eighty-seven percent (78/90) over 30 were anti-HCV positive. Those who tested anti-HCV positive had been injecting for an average of 12.0 years compared to 6.0 years for those were anti-HCV negative. The results for hepatitis B are to be reported fully at a later date. Sharing behaviour was also a factor although this was less important as an independent factor. Comparisons with earlier surveys suggested that there has not been a significant decline in the rate of sharing needles and syringes since the initial period following introduction of the needle exchange programme.

CONCLUSION

The prevalence of hepatitis C infection is common among injecting drug users of all ages. Without a significant reduction in sharing behaviour, particularly among younger injecting drug users, it is unlikely that the prevalence of hepatitis C among injecting drug users will decline in the future. Evidence suggests that the carriage of hepatitis C is higher than that of hepatitis B which would help explain the differing rates of prevalence. However, the risk of future transmission of other parenterally transmitted diseases remains high without a further significant decline in sharing behaviour.