Effects of Contamination of Freshwater Habitat With Common Heavy Metals and Anions on the Prevalence of Human Adenoviruses and Enteroviruses

Abstract

The occurrence and survival of enteric viruses in open surface waters can be impacted by a host of factors including fecal emission levels, seasonal variations, virus stability and the physicochemical parameters. In this research, we aimed to document the association between contaminations of water samples with human enteric viruses (adenoviruses and enteroviruses) from a freshwater lake with variations in chemical contaminants. We collected 216 water samples from October 2010 to April 2012, from a 4 km stretch along Lake Victoria (LV) basin in Homa Bay town located in the western region of Kenya. The samples were analyzed for the existence of human adenoviruses (HAdV) and human enteroviruses (HEV), using the nested PCR (nPCR). We also assessed in the water samples the levels of twelve chemical contaminants consisting of six heavy metal elements and six anions. About 8.3 % of the samples were found to be contaminated with the enteric viruses. The concentrations of the 12 chemical contaminants were found to be largely within the WHO suggested limits. Most of the chemical contaminants were not related to the detection rates of the viruses from the statistical analysis. However, some positive and negative associations between the viral genome's detection and the chemical concentrations were established for only three metals (Fe, Pb, Cd) and the PO43− Radical. Cd had a weak positive significant relationship with HAdV (rho = 0.146, p = 0.032) while Pb and Fe had a weak positive significant relationship with HEV genome detection (rho = 0.156, p = 0.022) and (rho = 0.148 and p = 0.029) respectively. There was a modest negative relationship between phosphate ions and HEV (rho = −0.174, p = 0.010). The results of our study do not provide support for the hypothesis of an association between the presence of human enteric viruses and the levels of twelve chemical contaminants.

Analysing the interplay of environmental virology, public health, and sanitation: a comprehensive review from a Kenyan perspective

“…( Haramoto et al., 2018 ) found that the most abundant class of enteric viruses was different on different types of matrices, indicating that systemic pollution influences community structure and composition. This supports the observation of ( Wasonga et al., 2021 ) and suggests that the matrix with high faecal pollution levels and minerology influences the viral community composition. Even less research has been done on other viral families, like hepatoviruses, as indicators of faecal pollution than on other environmental viruses and bacteria.…”

“…Studies from other regions of the country support the notion that changing the composition of some viral gene groups is a typical response to pollution, and a similar change in relative abundance has been observed in hydro-chemically contaminated areas of a freshwater matrix (Wasonga et al, 2021). However, because these observations are based on a small number of studies, it is challenging to predict with certainty the changes that will probably be seen in other environmental matrices and settings.…”