948 Sick with 180 Dead.  Outbreak began in January 2017.

According to South African health officials, on Friday 12th January, nine children under the age of 5 years presented to Chris Hani Baragwanath Hospital with febrile gastro-enteritis. The pediatrician suspected foodborne disease, including listeriosis, as a possible cause. The environmental health practitioners (EHPs) were informed and on the same day visited the crèche and obtained samples from two unrelated polony brands (manufactured by Enterprise and Rainbow Chicken Limited (RCL) respectively) and submitted these to the laboratory for testing.

Listeria monocytogenes was isolated from stool collected from one of the ill children, and from both of the polony specimens collected from the crèche. These isolates were sent to the NICD Centre for Enteric Diseases and underwent whole genome sequencing and genomic analysis. The ST6 sequence type was confirmed on all three isolates on Saturday 27th January.

Following the lead from the tests performed on these children from Soweto and the food they had ingested, the EHPs (Environmental Health Practitioners), together with the NICD and DAFF representatives, accompanied by 3 technical advisors from the World Health Organization in Geneva, visited a food-production site in Polokwane and conducted an extensive food product and environmental sampling.

Listeria monocytogenes was isolated from over 30% of the environmental samples collected from this site, which happens to be the Enterprise factory in Polokwane.

To conclude the investigation, whole genome sequencing analysis was performed from this Enterprise factory and the results became available midnight or last night. The outbreak strain, ST6, was confirmed in at least 16 environmental samples collected from this Enterprise facility.


As of 2 March 2018, 948 laboratory-confirmed listeriosis cases have been reported to NICD from all provinces since 01 January 2017. To date, 742 cases were reported in 2017, and 206 cases in 2018. Females account for 56% (517/917) cases where gender is reported. Where age was reported (n=914), ages range from birth to 92 years (median 19 years) and 41% (379/914) are neonates aged ≤28 days. Of neonatal cases, 96% (363/379) had early-onset disease (birth to ≤6 days). Most cases have been reported from Gauteng Province (59%, 558/948) followed by Western Cape (12%, 116/948) and KwaZulu-Natal (7%, 67/948) provinces. Cases have been diagnosed in both public (65%, 611/948) and private (35%, 337/933) healthcare sectors. Amongst 948 cases, specimens that were positive for Listeria monocytogenes were blood culture (691, 73%), cerebrospinal fluid (206, 22%) and other including stool, pus, urine or other body site (71, 7%). Additional data on a limited number of cases is available where completed case investigation forms have been submitted or provincial investigations have been conducted. Race distribution amongst 305 cases is black (259, 85%), colored (22, 7%), white (23, 7%) and Asian (1, <1%). Over 100 persons with laboratory-confirmed Listeria have been interviewed to obtain detailed food histories. Outcome is known for 659/948 (70%) patients of whom 180 (27%) have died.