Following the declaration of the Listeria outbreak in December 2017, a multi-sectoral outbreak response was initiated. Findings were shared by the Minister of Health, Dr. Aaron Motsoaledi at a public media briefing on 4 March 2018 (statement available at www.nicd.ac.za), and are summarized below. In addition, the National Department of Health requested a full recall of implicated processed meat products. According to Dr. Aaron Motsoaledi:
In our constant search for the source of the outbreak and the treatment of people who are affected, a team from the NICD has interviewed 109 ill people to obtain details about foods they had eaten in the month before falling ill. Ninety-three (85%) people reported eating ready-to-eat (RTE) processed meat products, of which polony was the most common followed by viennas/sausages and then other ‘cold meats’.
On Friday 12th January, nine children under the age of 5 years presented to Chris Hani Baragwanath Hospital with febrile gastro-enteritis. The paediatrician 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. Remember that in the last press conference I informed you that from clinical isolates obtained from patients (patient blood), 9 sequence types of Listeria monocytogenes were isolated and 91% were of sequence type 6 (ST6). We had then concluded that time that this outbreak is driven by ST6.
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 Organisation 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.
THE CONCLUSION FROM THIS IS THAT THE SOURCE OF THE PRESENT OUTBREAK CAN BE CONFIRMED TO BE THE ENTERPRISE FOOD-PRODUCTION FACILITY IN POLOKWANE
According to the Centre for Enteric Diseases (CED) and Division of Public Health Surveillance and Response, Outbreak Response Unit (ORU), National Institute for Communicable Diseases (NICD)/ National Health Laboratory Service (NHLS) the current number of ill and deceased are as follows:
As of 10 May 2018, 1033 laboratory-confirmed listeriosis cases have been reported to NICD from all provinces since 01 January 2017.
To date, 749 cases were reported in 2017, and 284 cases in 2018. Females account for 56% (549/979) cases where gender is reported. Where age was reported (n=985), ages range from birth to 93 years (median 18 years) and 41% (418/985) are neonates aged ≤28 days. Of neonatal cases, 96% (402/418) had early-onset disease (birth to ≤6 days). Most cases have been reported from Gauteng Province (59%, 605/1033) followed by Western Cape (13%, 130/1033) and KwaZulu-Natal (7%, 75/1033) provinces. Cases have been diagnosed in both public (63%, 652/1033) and private (35%, 359/1033) healthcare sectors. Amongst 1033 cases, 733 (73%) specimens that were positive for Listeria monocytogenes on blood culture, while 213 (21%) were positive on cerebrospinal fluid. Final outcome data is available for 68% (728/1033) of cases, of which 28% (204/728) died.
All healthcare workers are requested to complete case investigation forms (CIFs – available on the website) for case-patients with listeriosis, and submit these to the NICD (email@example.com ).
Clinical listeriosis management guidelines are available on the website (www.nicd.ac.za).
Where clinicians suspect listeriosis but specimens (including CSF and blood) are culture negative, a polymerase chain reaction (PCR)-based test can be performed at the NICD. PCR can also be performed on placenta samples for investigation of stillbirths/miscarriages.
Please contact the Centre for Enteric Diseases on (011) 555 0343 for further details.
The NICD continues to operate its 24-hour hotline for healthcare workers.