analysis of a 357 nt semi-conserved region of the 1,680 nt The sera of 46 Italian patients with chronic hepatitis HDV RNA genome in 13 isolates from different areas of the delta virus (HDV) infection were analyzed for HDV RNA world. 15 These genotypes appeared to have different geoby polymerase chain reaction (PCR) amplification. Gegraphic distributions: genotype I was present in North netic analysis of sequences amplified from two regions America, Europe, the Middle East, east Asia, and in the of the HDV genome indicated that all HDV RNA-positive South Pacific; genotype II has been found only in east Asia patients (98%) were infected with HDV genotype I. In (Taiwan and Japan) 16,17 ; and genotype III has been found Italy, infection with this genotype appeared to be associonly in northern South America. 15,18 The role of HDV genetic ated with a broad spectrum of chronic disease. No subvariations in determining the severity of type D hepatitis types of HDV genotype I were identified, nor were gehas not been conclusively determined, but some studies have netic variations clearly associated with different disease suggested an association between the severity of disease and patterns; however, clustering of some sequences suginfection with different HDV genotypes. 15,16 gested correlations with geography and transmission
In Italy, where HDV infection has been endemic, disease route. Italian HDV genotype I sequences were more diassociated with chronic HDV infection appears to have a biverse than those from east Asia and North America, sugmodal distribution. 5,19 While the majority of patients experigesting that HDV genotype I was likely introduced to ence a relatively benign, asymptomatic course that evolves Italy earlier and/or from multiple sources as compared to a stable cirrhotic condition, which in some cases might not to those areas. All sequences analyzed were predicted be significantly more severe than that due to the underlying to fold into the unbranched rod structure typical of HDV HBV infection, 14,19-22 10%-15% of cases exhibit a rapidly evolv-RNA. Within this structure, three conserved features ing, severe course of chronic disease. The genetic variations were identified, including sequences around the RNA of HDV were evaluated in this population to determine the editing site and the polyadenylation signal site. We condistribution of HDV genotypes in an area of longstanding clude that in Italy, where HDV infection has been enendemic HDV infection with variable disease patterns. demic, the overwhelmingly predominant genotype of HDV is genotype I. (HEPATOLOGY 1997;25:728-734.) PATIENTS AND METHODS Patients. Sera were obtained from 46 patients with chronic type D hepatitis (HDV). Twenty-nine patients (20 males, 9 females, mean Hepatitis delta virus (HDV) is a subviral infectious agent age 43 years, ranging 25-61 years of age) were hospitalized in the that requires simultaneous infection with hepatitis B virus Department of Gastroenterology, San Giovanni Rotondo Hospital.
(HBV). 1-3 Disease associated with both acute and chronic These 29 resided in or near the town of Foggia (southern Italy), a HDV infection is frequently more severe than that due to the region of high HDV endemicity. The clinical history of these patients Abbreviations: HDV, hepatitis delta virus; HBV, hepatitis B virus; IVDU, intravenous drug users; PCR, polymerase chain reaction; HDAg, hepatitis delta antigen.