Listeria source found - to be announced

The source of the world’s largest outbreak of listeriosis has been found.
The source of the world’s largest outbreak of listeriosis has been found.
Image: 123RF/ Vitaliy Vodolazskyy

The source of the world’s largest outbreak of listeriosis has been found and will be announced later on Sunday.

There have been almost 1‚000 patients and at least 176 deaths from the bacteria transmitted through food since January 2017.

As the outcomes of 18% of patients who were hospitalised for listeriosis are unknown‚ there might have been more deaths‚ according to the last update on the outbreak by the National Institute for Communicable Diseases (NICD).

Listeria monocytogenes bacteria is ubiquitous and can be found in food‚ water and soil.

Trying to find which food was infected once took five years in the USA.

This outbreak has been caused by a particularly virulent strain of listeria known as ST6 – that seems to be very infectious‚ scientists at the NICD said.

The NICD staff worked through the December holidays to identify the DNA of every patients’ listeria sample to work out if all patients were infected with the same bacteria.

Scientists cut their holidays short to complete testing.

The NICD and food industry has also tested 1‚500 food samples tested to find out which food is infected with the bacteria.

Over 100 patients‚ who had the disease‚ have been interviewed by epidemiologists to find out what they commonly eat. Mothers who lost infants to the disease‚ were also interviewed about food eaten.

This evidence from the standardised food questionnaires guided scientists on which food samples to test‚ Nevashan Govender‚ head of the emergency operations centre at the NICD said previously.

It was incredibly hard to work out what food is to blame for the disease‚ as listeria monocytogenes bacteria can remain in the body for 70 days before infection shows.

This means a person could have eaten the infected food two months before becoming ill.

It is believed the source is a factory or food processing plant in Gauteng that produces food eaten nationally.

This is because while most cases were in Gauteng‚ there were cases everywhere‚ especially in lower income communities.

The evidence is pointing towards inexpensive processed meat or dairy products kept in the fridge‚ NICD consultant Professor Lucille Blumberg aid earlier this week.

People at risk of listeriosis are pregnant mothers and those with a weakened immune system.

One in three babies infected from their mothers has died in this outbreak — -usually becoming sick in the first six days of life.

Listeria is killed through cooking food above 70 degrees Celsius- so the food in question is likely something that is ready to eat that doesn’t require cooking.


Would you like to comment on this article or view other readers' comments? Register (it’s quick and free) or sign in now.

Speech Bubbles

Please read our Comment Policy before commenting.