South Africa typhoid: ‘Contamination of municipal water is extremely unlikely to be the source’

February 18, 2022

Africa, Headlines

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In a follow-up on the report of multiple typhoid fever outbreaks in South Africa, the National Institute for Communicable Diseases reported on the clusters (small localized outbreaks) of typhoid, or enteric fever in Western Cape and North West provinces, including the possible source of infection.

During 2020 and 2021, although the total number of enteric fever cases across the country was similar to previous years (83 cases in 2020 and 110 cases in 2021), there was a relative increase in the number of cases reported from Western Cape and North West provinces.

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In Western Cape Province there are three clusters, each located in a different district (City of Cape Town Metropolitan, Cape Winelands and Garden Route) and in North West Province there is a cluster in Dr Kenneth Kaunda District. Although the first cases in all four clusters occurred in 2020, the presence of clusters in the respective districts only became evident in 2021 when additional cases were linked.

Clusters of S. Typhi in South Africa, January 2020 – January 2022*

Province	District	Number of cases	Date of first case	Date of most recent case
Western Cape	City of Cape Town Metropolitan	14	November 2020	January 2022
Western Cape	Cape Winelands	11	July 2020	May 2021
Western Cape	Garden Route	12	August 2020	December 2021
North West	Dr Kenneth Kaunda	16	November 2020	December 2021

*The results of WGS and cgMLST analysis are still pending for several isolates from cases detected in Western Cape and North West provinces during January 2022, so case numbers may change as these results become available.

Contamination of municipal water is extremely unlikely to be the source of infection in any of these clusters, due to the demographics of the cases (including their age profiles, places of residence, source(s) of drinking water and access to improved sanitation) and the scale (each cluster having fewer than 20 cases which stretch over a period of 2 years). It is very likely that there are complex chains of transmission within the respective communities, mostly due to the presence of unrecognized cases and carriers who serve as reservoirs of infection and lead to ongoing transmission. This makes it challenging to investigate and pin point source(s) within the communities.