Microbial assessment of water, sanitation, and hygiene (WaSH) in temporary and permanent settlements two years after Nepal 2015 earthquake

Sital Uprety, Samendra P. Sherchan, Preeti Narayanan, Bipin Dangol, Marika Maggos, Alex Celmer, Joanna Shisler, Mohan Amarasiri, Daisuke Sano, Thanh H. Nguyen

Research output: Contribution to journalArticlepeer-review

Abstract

Disaster-induced displacement often causes people to live in temporary settlements that have limited infrastructure and access to water, sanitation, and hygiene (WaSH). Reducing the risk of diarrheal diseases in such situations requires knowing how housing influences the presence of pathogens in water and the interaction between human settlements and exposure to pathogens. A cross-sectional study was conducted in May 2017 in two communities hard-hit by the Nepal 2015 earthquake: one recovered with newly reconstructed houses, and one recovered with residents still living in sheet metal temporary shelters constructed after the earthquake. We collected 60 water (30 drinking water and 30 cleaning water), 30 hand rinse, and 90 environmental swab samples (30 toilet handles, 30 utensils, and 30 water vessels) from selected households in each location and quantified 22 bacterial pathogens using microfluidic quantitative polymerase chain reaction (mfqPCR). A total of 59 samples were randomly selected for amplicon-based sequencing of the 16S rRNA, and it identified bacterial community profiles between these two settlements and their association with target genes of pathogenic bacteria. Target genes like uidA of Escherichia coli and the mip gene of Legionella pnuemophila showed significantly high frequency in specific sample types in temporary settlements than in permanent settlements. A significantly high concentration was observed in temporary settlements for Enterococcus spp. and S. typhimurium, specifically in swab samples. There was a sharp distinction of microbial community profiles between water and hand rinse samples with environmental swab samples, with a large abundance of potentially pathogenic bacteria in swab samples in both settlements. This observation highlighted that fomite could be an important transmission route for pathogens in rural settings and designing key interventions to target different stages of transmission pathways is essential. Overall findings from this study suggest that the recovered settlement with higher quality housing may be less impacted by fecal contamination than recovering settlements and that interventions should be designed to disrupt multiple transmission pathways to reduce pathogen exposure.

Original languageEnglish (US)
Article number162867
JournalScience of the Total Environment
Volume877
DOIs
StatePublished - Jun 15 2023

Keywords

  • Earthquake
  • Housing
  • Intervention
  • Pathogen
  • WaSH
  • qPCR

ASJC Scopus subject areas

  • Pollution
  • Waste Management and Disposal
  • Environmental Engineering
  • Environmental Chemistry

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