An additional 53 cases and one death have been recorded by the National Institute of Communicable Diseases (NICD). 13 cases occurred during 2017 and were retrospectively reported.
Outcome data is available for 29% (238/820) of cases, of which 82 died.
A total of 820 laboratory-confirmed listeriosis cases have now been reported to NICD since January 2017.
Most are from Gauteng Province (59%), Western Cape (13%) and KwaZuluNatal (7%) provinces.
It is already by far the largest ever Listeria outbreak, according to the World Health Organization (WHO).
False reports of outbreak source
Genetic testing on Listeria from patients suggests a single strain, sequence type 6 (ST6), is responsible for the majority of infections.
However, it has not been found in samples from processing facilities, abattoirs or food from patients’ homes.
Tensions are mounting as rumours circulate about the source of the outbreak.
The Nelson Mandela Bay municipality hit out at ‘unfounded allegations’ that its tap water was one of the causes.
“The institution would like to condemn individuals who have been spreading inaccurate and irresponsible information about this serious issue through social media.
“This misinformation has not only caused panic across the city, it has also led to undue pressure on our Service Delivery Call Centre, which we use to deal with water leaks among others.”
Another rumour is apples are the source of the pathogen.
Hortgro, the deciduous fruit industry body, said according to its knowledge no Listeria had ever been found on fresh South African apples.
“A report is currently being circulated on certain WhatsApp groups which refer to an incident dating back to 2015 in California in the USA when Listeria was found on caramelised apples,” Anton Rabe, Hortgro’s executive director.
“To link this to the current situation and in any manner or form with the fruit industry as such is misleading and sensation-seeking.”
No cases in Europe - ECDC
South Africa has made listeriosis a notifiable disease meaning every diagnosed patient must be reported.
Infection is primarily affecting pregnant women, neonates, elderly and immuno-compromised people.
The first documented outbreaks occurred in 1977 (14 cases) and 2015 (seven) and since only sporadic infections have been detected in the country.
The European Centre for Disease Prevention and Control (ECDC) said since October 2017 an increase in the number of neonatal cases was observed.
“This increase and the associated deaths are of concern, as South Africa’s also has high prevalence of HIV infection. In addition, poorly regulated street food vendors are common across South Africa. Many people lack access to electricity and thus refrigeration.
“Based on WGS analysis, no associated cases were reported in EU/EEA countries. The risk of spread to Europe is very low.”
European travellers should consume only bottled drinks and factory-produced ice cubes; avoid unpasteurised milk and milk products; ensure meat and fish are thoroughly cooked; properly wash fruits and vegetables and consider general hygiene conditions when consuming local products, such as freshly made fruit juices, coconut water, drinks and cocktails to reduce risk of infection.