What is it about?
We studied river and sewage water in Blantyre, Malawi, for 19 months to look for Salmonella bacteria. We found many different types, including strains that can cause serious bloodstream infections and strains resistant to antibiotics. We also discovered that one type carried a gene thought to be unique to typhoid, which raises questions about how well some tests work for tracking typhoid in the environment. Our results show that environmental monitoring can help identify dangerous Salmonella strains in places where clinical testing is limited.
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Photo by MChe Lee on Unsplash
Why is it important?
This is the first study to show that strains of Salmonella linked to serious bloodstream infections in Africa can be found in river and sewage water in Malawi. We also highlight problems with current tests for detecting typhoid in the environment. These findings show that environmental monitoring can reveal hidden risks and improve how we track and control Salmonella in places where clinical testing is limited.
Perspectives
During my PhD I focused on tracking typhoid in water samples, but along the way we discovered many other types of Salmonella. Writing this article has been especially rewarding because it allowed me to explore that hidden diversity, highlight strains that pose public health risks, and share findings that were unexpected when the study began.
Jonathan Rigby
Imperial College London
Read the Original
This page is a summary of: Diversity of Salmonella enterica isolates from urban river and sewage water in Blantyre, Malawi, PLoS Neglected Tropical Diseases, September 2025, PLOS,
DOI: 10.1371/journal.pntd.0012413.
You can read the full text:
Resources
Optimized methods for detecting Salmonella Typhi in the environment using validated field sampling, culture and confirmatory molecular approaches
This article discusses the protocol development that was used to sample and isolate Salmonella from river water in Blantyre, Malawi.
Environmental surveillance for Salmonella Typhi in rivers and wastewater from an informal sewage network in Blantyre, Malawi
This article discusses the results of S. Typhi surveillance in Blantyre, Malawi, at the conclusion of the study.
To develop and optimise methods for the detection and isolation of Salmonella Typhi from the environment. Student Doctoral thesis
Student Doctoral Thesis for the full study of Salmonella water surveillance in Blantyre, Malawi
Contributors
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