An Observational Study on the Prevalence of Chronic Hepatitis D in Romania and the Efficacy of Treatment With Pegasys (Peginterferon Alfa-2a)

Inclusion Criteria: For epidemiological part of the study: * Adult patients \>/= 18 years of age * Positive HBsAg for at least 6 months For the non-interventional section of the study * Adult patients, \>/= 18 years of age * Positive HBsAg for at least 6 months * Positive anti-delta and positive HDV RNA by PCR * Elevated serum ALT \>/= 2x ULN Exclusion Criteria: Patients with any of the following will not be eligible for treatment with Pegasys: * History of neurological disease * History of severe psychiatric disease * Decompensated diabetes * History of immunologically mediated disease * History of severe cardiac disease * History or other evidence of severe chronic pulmonary disease * Inadequate hematologic function