Prevalence of protozoa, viruses, coliphages and indicator bacteria in groundwater and river water in the Kathmandu Valley, Nepal

A significant prevalence of waterborne pathogens was found in groundwater and river water samples from the Kathmandu Valley, Nepal, during the rainy season of 2009. The study detected at least one type of pathogen—including Cryptosporidium, Giardia, human adenoviruses, and noroviruses—in 56% of shallow well samples tested. River water exhibited notably higher concentrations of these pathogens compared to groundwater, with Cryptosporidium and Giardia levels reaching 140 oocysts/l and 8500 cysts/l, respectively. The research also demonstrated that E. coli-positive groundwater samples were more likely to contain protozoa and viruses, suggesting its potential as an indicator for pathogen contamination in valley groundwater. Additionally, genotyping of F-RNA coliphages was successfully used to differentiate between human and animal fecal sources.

Haramoto, E., Yamada, K., & Nishida, K. (2011). Prevalence of protozoa, viruses, coliphages and indicator bacteria in groundwater and river water in the Kathmandu Valley, Nepal. Transactions of the Royal Society of Tropical Medicine and Hygiene, 105(12), 711–716. https://doi.org/10.1016/j.trstmh.2011.08.004