Genomic surveillance of a climate amplified cholera outbreak in Malawi 2022-2023
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
In the aftermath of 2 extreme weather events in 2022, Malawi experienced a severe cholera outbreak; 59,325 cases and 1,774 deaths were reported by March 31, 2024. We generated 49 Vibrio cholerae full genomes from isolates collected during December 2022–March 2023. Phylogenetic and phylogeographic methods confirmed that the Malawi outbreak strains originated from Pakistan’s 2022 cholera outbreak. That finding aligns with substantial travel between the 2 countries. The estimated most recent ancestor of this lineage was from June–August 2022, coinciding with Pakistan’s floods and cholera surge. Our analysis indicates that major floods in Malawi contributed to the outbreak; reproduction numbers peaked in late December 2022. We conclude that extreme weather events and humanitarian crises in Malawi created conditions conducive to the spread of cholera, and population displacement likely contributed to transmission to susceptible populations in areas relatively unaffected by cholera for more than a decade.
Date Issued
2025-06-01
Date Acceptance
2025-03-19
Citation
Emerging Infectious Diseases, 2025, 31 (6), pp.1090-1099
ISSN
1080-6040
Publisher
Centers for Disease Control and Prevention
Start Page
1090
End Page
1099
Journal / Book Title
Emerging Infectious Diseases
Volume
31
Issue
6
Copyright Statement
Copyright © 2025 The Author(s). This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Date Publish Online
2025-05-20