Prevalence, Distribution, and Genotypes of Adenovirus and Norovirus in the Puzi River and Its Tributaries and the Surrounding Areas in Taiwan

This study investigated the prevalence, distribution, and genotypes of adenoviruses (AdVs) and noroviruses (NoVs) in the Puzi River and surrounding areas in Taiwan. The viruses in the water samples were isolated using the membrane filtration method and the viral nucleic acids were extracted. The RNA of NoVs was reverse-transcribed into complementary DNA using reverse transcriptase-polymerase chain reaction. AdVs and NoVs were detected using nested PCR. Genotyping and phylogenetic analyses were performed to identify the various viral genotypes in the water samples. Human adenovirus (HAdVs) and porcine adenovirus (PAdVs) were the predominant genotypes in the water samples. The prevalence of F species HAdVs serotype 41 (79.2%) and C species PAdVs serotype 5 (18.1%) was higher than that of other serotypes. Among NoVs, genogroup GII was more prevalent than GI. In particular, GII.4 (21.2%) and GII.17 (18.2%) were the predominant genotypes, which was consistent with the clinical findings. The prevalence of both AdVs and NoVs was higher in the winter than spring, summer and autumn seasons. AdVs and NoVs detection results were statistically analyzed by investigating their association with water quality indicators. The results revealed that the presence of AdVs was significantly correlated with the heterotrophic bacterial count, total coliform Escherichia coli, turbidity, salinity, and dissolved oxygen. Meanwhile, the presence of NoVs was only significantly correlated with temperature, pH, and dissolved oxygen. Microbial pollution sources may include urban runoff and discharge of water from livestock farms situated near the river and tributaries within this region of Taiwan. Future studies should include comparisons of the presence of AdVs and NoVs in these known pollution sources and water quality monitoring of these watersheds, as this will allow potential identification of pollution sources. Additionally, remediation strategies must be developed to minimize viral contamination in the river ecosystem. Plain Language Summary Adenovirus and norovirus contamination in the river and coastal ecosystem were associated with several infections and health risks such as gastrointestinal and respiratory diseases in humans and animals. In this work, we have investigated the occurrence, distribution and genotypes of adenovirus and norovirus in the Puzi River, its tributaries, Dongshi fishing port and nearby coastal oyster breeding area in four seasons. We have found that the Puzi River has shown a higher prevalence of adenovirus and norovirus than other study sites and the incidence of both viruses was high in the winter season. Human adenovirus 41, porcine adenovirus 5, norovirus GII.4 and GII.17 were the predominant in the water samples. The outflow from the nearby livestock wastewater channels and urban runoff into the river and coastal ecosystem may be a source of contamination of the study sites. The occurrence of both the viruses is significantly correlated with the water quality parameters, which suggested that adenovirus and norovirus are some of the potential water quality indicators. Further, identifying the natural and anthropogenic activities in the contaminated sites can aid in framing the risk management strategies of the related river and coastal ecosystem.