National Institute for Communicable Diseases (NICD), updated the outbreak of Listeria on 3 May 2018.

As of 24 April 2018, a total of 1,024 laboratory-confirmed listeriosis cases have been reported to NICD since 01 January 2017. Since the recall 7 weeks ago, a total of 55 cases have been reported, whereas for the 7 weeks prior to the recall, 169 cases were reported. All cases that have been identified after the recall are being fully investigated.

Prior to 2017, an average of 60 to 80 laboratory-confirmed listeriosis cases per year (approximately 1 per week), were reported in South Africa. In July 2017, an increase in laboratory-confirmed cases of listeriosis was reported to National Institute for Communicable Diseases (NICD) which was followed by investigations into the reported increase. On 05 December 2017, the listeriosis outbreak was declared by the Minister of Health, Dr. Aaron Motsoaledi.

The source of the outbreak was identified as ready-to-eat processed meat products manufactured at Enterprise Foods’ Polokwane production facility. A recall of affected products was initiated on 04 March 2018.

1,024 cases have been reported from 01 January 2017 to 24 April 2018. The number of reported cases has decreased since the implicated products were recalled on 04 March 2018.  Neonates ≤28 days of age are the most affected age group, followed by adults aged 15 – 49 years of age. Most cases have been reported from Gauteng Province (59%,601/1 024), followed by Western Cape (13%, 128/1 024) and KwaZulu-Natal (7%, 73/1 024) provinces.  There are 200 reported deaths.

Whole-genome sequencing analysis has been performed on 521 clinical isolates to date. Of these, 85% (443/521) were identified as sequence type (ST) 6. The remaining isolates (15%, 83/521) represented 19 sequence types including, ST1, ST54, ST876, ST2, ST5, ST204, ST219. ST224, ST71, ST101, ST121, ST155, ST3, ST403, ST515, ST7, ST8 and ST88.

Whole genome sequencing has been performed on 595 food and environmental isolates. Of these, 13% (79/595) were identified as ST6. The remaining isolates (87%, 516/595) represented 26 sequence types, including ST20, ST1, ST121, ST5. ST321, ST9, ST155, ST2, ST3, ST87, ST120, ST378, ST101, ST108, ST2288, ST31, ST7, ST11, ST122, ST14, ST37, ST4, ST54, ST76 and ST88.

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