Virus contamination of centralized water supply systems as a health risk factor: features of long-term dynamics in the Russian Federation

Despite the fact that high-quality water treatment is currently being carried out, there is a possibility that pathogens of infectious diseases may enter a water supply network. Sanitary and virologic control of water sources and drinking water is currently performed directly by direct detection of viruses, as well as by using indirect indicators of viral contamination, namely, coliphages.

The aim was to study the spectrum of viruses contained in water from a centralized water supply system using laboratory diagnostic methods regulated to determine rated indicators.

Over 2014–2023, water samples were taken from a centralized water supply system (n = 2,847,568). The dynamics and structure of water contamination with hepatitis A (HAV), Rotavirus, Enterovirus, Norovirus, Astrovirus, COVID-19 (SARs-CoV-2) viruses, and Adenovirus in a centralized water supply system were described using classical cultural methods of bacteriology and virology, molecular-genetic and serological methods.

The conducted research found that over 2014–2023, the average proportion of centralized water supply samples that did not meet sanitary and hygienic standards in the Russian Federation was 0.57 % for the presence of viruses and 0.21 % for the presence of coliphages for the period from 2014 to 2023. The proportion of centralized water supply samples per non-conforming Rotavirus contents was 1.41 % (95 % СI: 1.33–1.49) (according to serological studies, 0.08 % of samples (95 % CI: 0.06–0.10); Enterovirus, 0.71 % (95 % CI: 0.57–0.86) (according to PCR studies, 0.37 % (95 % CI: 0.33–0.42); Adenovirus, 0.52 % (95 % CI: 0.38–0.70); Norovirus, 0.20 % (95 % CI: 0.16–0.24); Astrovirus, 0.14 % (95 % CI: 0.11–0.18); SARs-CoV-2, 0.09 % (95 % CI: 0.03–0.20); HAV, 0.2 % (95 % CI: 0.01–0.04) (according to serological studies, it was slightly higher (0.09 % (95 % CI: 0.07–0.11). A direct strong correlation was established between the proportion of centralized water supply samples that did not meet sanitary and epidemiological requirements and the presence of coliphages and pathogens of viral infections (r > 0.8); however, determination of nucleic acids in drinking water by molecular genetic methods indicates higher prevalence of viruses as compared to classical coliphage testing.

The structure of virus contamination in water from a centralized water supply system was represented by Rotavirus (52.6 ± 0.3 %), Adenovirus (18.8 ± 0.5 %), Enterovirus (13.9 ± 0.2 %), Norovirus (7.5 ± 0.1 %), Astrovirus (3.8 ± 0.1 %), and SARs-CoV-2 (3.4 ± 0.2 %) over 2020–2023.