Urban sanitation infrastructure is inadequate in many low-income countries, leading to the presence of highly concentrated, uncontained fecal waste streams in densely populated areas. Combined with mechanisms of aerosolization, airborne transport of enteric microbes and their genetic material is possible in such settings but remains poorly characterized. We detected and quantified enteric pathogen-associated gene targets in aerosol samples near open wastewater canals (OWCs) or impacted (receiving sewage or wastewater) surface waters and control sites in La Paz, Bolivia; Kanpur, India; and Atlanta, USA, via multiplex reverse-transcription qPCR (37 targets) and ddPCR (13 targets). We detected a wide range of enteric targets, some not previously reported in extramural urban aerosols, with more frequent detections of all enteric targets at higher densities in La Paz and Kanpur near OWCs. We report density estimates ranging up to 4.7 × 102gc per mair3across all targets including heat-stable enterotoxigenicEscherichia coli,Campylobacter jejuni, enteroinvasiveE. coli/Shigellaspp.,Salmonellaspp., norovirus, andCryptosporidiumspp. Estimated 25, 76, and 0% of samples containing positive pathogen detects were accompanied by culturableE. coliin La Paz, Kanpur, and Atlanta, respectively, suggesting potential for viability of enteric microbes at the point of sampling. Airborne transmission of enteric pathogens merits further investigation in cities with poor sanitation.
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant Number 1653226. Many thanks go to the authors’ colleagues at IIT-Kanpur including Hari Shankar, Harish Vishwakarma, Shivshankar Mishraa, and numerous others who helped with instrumentation and shared their laboratory space. The authors further acknowledge the kind people who shared their homes and their tea with them as they sampled in the community. Thanks also go to all of the authors’ colleagues at Universidad Católica Boliviana and Universidad Mayor de San Andrés, including undergraduate assistants.
© 2021 The Authors. Published by American Chemical Society
- enteric pathogens
- environmental health
- urban sanitation