The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water

Abhilasha Karkey, Thibaut Jombart, Alan W. Walker, Corinne N. Thompson, Andres Torres, Sabina Dongol, Nga Tran Vu Thieu, Duy Pham Thanh, Dung Tran Thi Ngoc, Phat Voong Vinh, Andrew C. Singer, Julian Parkhill, Guy Thwaites, Buddha Basnyat, Neil Ferguson, Stephen Baker

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Abstract

One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley.

Original languageEnglish
Article numbere0004346
Pages (from-to)1-18
Number of pages18
JournalPLoS Neglected Tropical Diseases
Volume10
Issue number1
DOIs
Publication statusPublished - 6 Jan 2016

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Salmonella paratyphi A
Salmonella typhi
Drinking Water
Typhoid Fever
Water
Water Quality
rRNA Genes
Water Pollution
Nepal
United Nations
Conservation of Natural Resources
Nitrates
Public Health
Guidelines
Bacteria
DNA

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The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water. / Karkey, Abhilasha; Jombart, Thibaut; Walker, Alan W.; Thompson, Corinne N.; Torres, Andres; Dongol, Sabina; Tran Vu Thieu, Nga; Pham Thanh, Duy; Tran Thi Ngoc, Dung; Voong Vinh, Phat; Singer, Andrew C.; Parkhill, Julian; Thwaites, Guy; Basnyat, Buddha; Ferguson, Neil; Baker, Stephen.

In: PLoS Neglected Tropical Diseases, Vol. 10, No. 1, e0004346, 06.01.2016, p. 1-18.

Research output: Contribution to journalArticle

Karkey, A, Jombart, T, Walker, AW, Thompson, CN, Torres, A, Dongol, S, Tran Vu Thieu, N, Pham Thanh, D, Tran Thi Ngoc, D, Voong Vinh, P, Singer, AC, Parkhill, J, Thwaites, G, Basnyat, B, Ferguson, N & Baker, S 2016, 'The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water' PLoS Neglected Tropical Diseases, vol. 10, no. 1, e0004346, pp. 1-18. https://doi.org/10.1371/journal.pntd.0004346
Karkey, Abhilasha ; Jombart, Thibaut ; Walker, Alan W. ; Thompson, Corinne N. ; Torres, Andres ; Dongol, Sabina ; Tran Vu Thieu, Nga ; Pham Thanh, Duy ; Tran Thi Ngoc, Dung ; Voong Vinh, Phat ; Singer, Andrew C. ; Parkhill, Julian ; Thwaites, Guy ; Basnyat, Buddha ; Ferguson, Neil ; Baker, Stephen. / The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water. In: PLoS Neglected Tropical Diseases. 2016 ; Vol. 10, No. 1. pp. 1-18.
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