16 October 2019

Listeriosis: No new outbreak, annual cases actually below expected range

A total of 87 cases of listeriosis were reported during the past year. While this number may seem high, it is in fact below what was expected.

The National Institute for Communicable Diseases said on Wednesday that reported listeriosis cases in the last year were below what could reasonably be expected, despite 21 deaths.

This comes after the 2017/2018 outbreak that killed more than 180 South Africans.

Data for South Africa from 2013 show that prior to the 2017/2018 listeriosis outbreak, 55 to 113 cases per year were reported (see below). 


                                                                                                                                  Supplied (NCID)

By the end of December 2018, 640 cases had been confirmed and deaths had doubled to 60, according to News24. Three months later, at the beginning of March this year, 180 people had died and just under 1 000 cases had been confirmed. The outbreak sparked panic among South Africans, considering it was the largest ever in South Africa.

SEE: How SA's deadly listeriosis outbreak unfolded

However, rumours of another listeriosis outbreak were put to bed yesterday after the National Institute for Communicable Diseases (NCID) released a statement, saying that there is no evidence of another outbreak.

In fact, the release states that for the 12 months following the official end of the 2017/2018 outbreak (3 September 2018 – 18 September 2019), a total of 87 laboratory-confirmed listeriosis cases were reported – a number that is below the expected range for sporadic disease. 

No unusual trends

Data to detect possible clusters or outbreaks are analysed on an ongoing basis and the institute further explains that there have been no unusual trends in the epidemiological patterns of disease, or in the whole genome sequencing analysis in order to detect possible clusters or outbreaks. 

The NCID also added that since listeria monocytogenes is ubiquitous in the environment, it is likely that accidental contamination of food occurs fairly frequently, and that consumption of contaminated food may lead to listeriosis particularly in vulnerable people.

At our current population size of 58.8 million, we would expect 117 to 294 sporadic cases in South Africa per year. 

Class action suit could take years

The source of the listeriosis outbreak had been traced back to a factory owned by Tiger Brands unit Enterprise Foods in March last year. After the discovery, the manufacturer of processed meats shut down a number of its factories and had a massive recall of cold meat products.

Following this, they found themselves in a class action brought against them by more than 1 000 people affected by the outbreak, News24 reports

However, the article goes on to mention that Richard Spoor Attorneys, who are representing those that were affected, explained the case could be delayed "for years" as Tiger Brands had issued subpoenas against food-testing laboratories.

Their aim is to obtain information about the identities of people or parties who submitted samples for testing listeriosis and the results of those tests during the period of the outbreak. 

A statement by the company in December last year said it would follow the legal process to bring closure to all parties, and that no liability has been established against the company for the listeriosis outbreak.

"However, should liability be determined, the company will respond appropriately to any legitimate claims," the statement read.

Image: iStock


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