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Long-term changes in the frequency and outcome of hepatitis delta virus (HDV) infection have seldom been analysed. This retrospective, longitudinal study includes 398 consecutive hepatitis B surface antigen (HBsAg)-positive patients with anti-HDV antibodies who attended our institution between 1983 and 2008. At enrolment, 182 patients had acute and 216 chronic hepatitis. Patients were grouped into two periods. Those who attended between 1983 and 1995 and those between 1996 and 2008. The former group was significantly younger, mainly intravenous drugs users, and had a greater incidence of acute HDV and HIV and HCV coinfection. Patients with acute HBV/HDV coinfection cleared both infections in 90% of cases, while all patients with HDV superinfection evolved to chronic disease. One hundred and fifty-eight patients with chronic HDV were followed for a median period of 158months. Seventy-two per cent of the patients remained stable, 18% had hepatic decompensation, 3% developed hepatocellular carcinoma, and 8% cleared HBsAg. Liver-related death was observed in 13% of patients and mainly occurred in patients from the first period (P=0.012). These results indicate an outbreak of HDV at the end of the 1980s and the beginning of the 1990s, with a large number of acute HDV cases affecting predominately young, male intravenous drug users. Currently, patients with chronic HDV disease are older, and factors associated with worse prognosis include the presence of cirrhosis and age at the time of diagnosis.

This study contributes greatly to understanding the usefulness of genotypes of F-specific RNA bacteriophages in source tracking of faecal wastes.

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The effect of natural inactivation in freshwater, chlorination, ammonia, extreme pHs, temperature, and salt content on phage inactivation was evaluated on mixtures of F-specific RNA bacteriophage isolates belonging to genotypes I, II, III, and IV. The bacteriophages studied were previously but recently isolated from natural samples, characterized as F-specific RNA bacteriophages and genotyped by plaque hybridization with genotype-specific probes. Natural inactivation in river water was modeled by in situ incubation of bacteriophages inside submerged dialysis tubes. After several days bacteriophages of genotype I showed the highest persistence, which was significantly different from that of bacteriophages of genotype II, IV, or III. The pattern of resistance of phages belonging to the various genotypes to extreme pHs, ammonia, temperature, salt concentration, and chlorination was similar. In all cases, phages of genotype I showed the highest persistence, followed by the phages of genotypes II, III, and IV. The phages of genotypes III and IV were the least resistant to all treatments, and resistance of genotypes III and IV to the treatments was similar. Bacteriophages of genotype II showed intermediate resistance to some of the treatments. The resistance of four phages of genotype I to natural inactivation and chlorination did not differ significantly. These results indicate that genotypes III and IV are much more sensitive to environmental stresses and to treatments than the other genotypes, especially than genotype I. This should be taken into consideration in future studies aimed at using genotypes of F-specific RNA bacteriophages to fingerprint the origin of fecal pollution.Fecal contamination of aquatic environments can hinder contact recreation and shellfish growing water and spoil drinking water, since it may include pathogenic microorganisms. There is a general belief that exposure to waters polluted with human feces is more hazardous than exposure to waters polluted with animal feces, although no sound epidemiological studies support this view. However, regardless of the health risks involved, management of fecal contamination of water can only improve if the sources of pollution are identified by water analysis and thus tools to distinguish between human and animal fecal sources are needed. Chemical and microbiological methods had been proposed for tracking the origin of fecal contaminants. Fecal sterols of human and animal origin have been used for this purpose (22). Microbiological indicators include the following: ratios of fecal coliforms to fecal streptococci (13); the presence of Rhodococcus coprophilus (23); the presence of some phenotypes (24) and ribotypes (25) of Bifidobacterium species; the presence of some phenotypes of Bacteroides species (21); the distribution patterns of ribotypes of Escherichia coli (7, 29); the distribution patterns of repetitive DNA sequences of E. coli (8); antibiotic resistance patterns (15); bacteriophages specific for various strains of Bacteroides fragilis (36); ph...