Listeria monocytogenes. Picture: Centres for Disease Control and Prevention
Cape Town - In December 2017 the national government officially declared a listeriosis outbreak, triggering a multi-sectoral outbreak response which included the National Institute for Communicable Diseases (NICC), the National Health Laboratory Services and the Health Department.

Some of the investigative measures have included sampling of foods identified in laboratory-confirmed cases, detailed case investigation forms completed by public and private clinicians, laboratories and hospitals, the sampling of retail and manufacturing facilities by environmental health practitioners and molecular epidemiological investigations.

Intensive data collection efforts have revealed that the total number of patients diagnosed with listeria in the past six months stands at 948. Of these, the outcome for 659 (70%) cases are known.

Of the 659 cases where the outcomes are known, 180 (27%) of patients died before the source of the outbreak was identified. 

Here is a breakdown of the investigations which isolated the source of the outbreak:

Epidemic curve of laboratory-confirmed listeriosis cases by epidemiological week and date of sample collection and province.
Epidemic curve of laboratory-confirmed listeriosis cases by epidemiological week and date of sample collection and province from 01 January 2017 to 2 March 2018. Graphic: NICC

Distribution of laboratory-confirmed cases of listeriosis by district in South Africa for 01 January 2017 to 2 March 2018.
Distribution of laboratory-confirmed cases of listeriosis by district in South Africa for 01 January 2017 to 2 March 2018. Graphic: NICC


Epidemic curve of laboratory-confirmed listeriosis cases by epidemiological week and date of sample collection and province from 01 January 2017 to 2 March 2018.
Epidemic curve of laboratory-confirmed listeriosis cases by epidemiological week and date of sample collection and province from 01 January 2017 to 2 March 2018. Graphic: NICC

* All data supplied by the National Institute for Communicable Diseases.

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