Waterborne infections in the era of bioterrorism

Safe drinking water and waterborne outbreaks

The present work compiles a review on drinking waterborne outbreaks, with the perspective of production and distribution of microbiologically safe water, during 2000-2014. The outbreaks are categorised in raw water contamination, treatment deficiencies and distribution network failure. The main causes for contamination were: for groundwater, intrusion of animal faeces or wastewater due to heavy rain; in surface water, discharge of wastewater into the water source and increased turbidity and colour; at treatment plants, malfunctioning of the disinfection equipment; and for distribution systems, cross-connections, pipe breaks and wastewater intrusion into the network. Pathogens causing the largest number of affected consumers were Cryptosporidium, norovirus, Giardia, Campylobacter, and rotavirus. The largest number of different pathogens was found for the treatment works and the distribution network. The largest number of affected consumers with gastrointestinal illness was for contamination events from a surface water source, while the largest number of individual events occurred for the distribution network.

Changing epidemiology of HCV and HBV infections in Northern Italy: a survey in the general population

AIM

To evaluate the hepatitis B virus (HBV) and the hepatitis C virus (HCV) epidemiology in the general population of Northern Italy, a cohort of 965 subjects, all residents (including 47 immigrants), were anonymously tested for HBV and HCV infections.

MATERIAL AND METHODS

Serum samples were assayed for anti-HCV and anti-HBV markers by enzyme-linked immunosorbent assay and for HCV-RNA by polymerase chain reaction, and the positive cases were genotyped. HBsAg-positive cases were assayed for HBeAg/anti-HBe, whereas HBsAg negatives were tested for both anti-HBc and anti-HBs.

RESULTS

The overall prevalence of anti-HCV was 2.6%, with a bimodal distribution characterized by the highest prevalence (12%) in subjects over 75 years old. None of the subjects under 25 years old was anti-HCV positive. Anti-HCV positivity was similar in males and females (2.4% vs. 2.7%). HCV-RNA was positive in 40% of cases and genotype 1 was the most common. The HBsAg prevalence was 1%, with a significant difference according to country of origin (0.8% in Italian subjects vs. 6.4% in immigrants, P=0.01). HBsAg positivity increased significantly with age (R2=0.57, P<0.02). The overall percentages for the prevalence of isolated anti-HBs, anti-HBs+/anti-HBc+, and isolated anti-HBc were 23.8%, 8.4%, and 4.2%, respectively.

CONCLUSIONS

Our study provides a new picture of HCV and HBV epidemiology in Northern Italy, with these features: (1) a cohort effect showing a reduction of HCV infection in the elderly, possible due to age-related mortality; (2) an unchanged overall prevalence of HBV infection, despite continuing immigration of subjects from endemic countries.