Listeriosis outbreak: How it started, how it was traced, and how it was finally stopped

The deadly listeriosis outbreak that killed more than 180 South Africans is finally a thing of the past, Health Minister Aaron Motsoaledi announced on Monday.

Addressing a media conference at the offices of the National Institute for Communicable Diseases (NICD) in Johannesburg, Motsoaledi said that no new cases of listeriosis had been reported in the past three months and that processed meat products – such as polony, russians and viennas – were again considered safe for human consumption.

The listeriosis outbreak in South Africa was first noted in October last year, when the NICD discovered an increase in listeria throughout South Africa, with more than 365 documented cases.

Listeriosis is a bacterial infection that can cause severe illness - including severe sepsis, meningitis, or encephalitis - sometimes resulting in lifelong harm and even death.

On December 5, 30 people had already died and Motsoaledi announced a listeriosis outbreak.

By the end of December, 640 cases had been confirmed and deaths had doubled to 60.

Three months later, at the beginning of March, 180 people had died and just under 1 000 cases had been confirmed.

The NCID’s team tasked with finding the source of the outbreak worked relentlessly for months, taking no time off, starting workdays at 05:30 and facing "hectic exhaustion".

"At many stages, we were despairing," Dr Juno Thomas, head of the NICD's Centre for Enteric Diseases, told News24 at the time.

The breakthrough came when, on January 12, nine children under the age of five from a crèche in Soweto were taken to the Chris Hani-Baragwanath Hospital and a paediatrician suspected a foodborne disease, possibly listeriosis.

Environmental health practitioners were informed and visited the crèche and took samples from two polony brands manufactured by Enterprise and Rainbow Chicken Limited, and from the stool of one of the ill children.

These samples were sent for analysis and gave the team the breakthrough that they had been working so hard for.

Source of outbreak

On March 4, Motsoaledi announced that the team had managed to trace the source of the listeriosis outbreak strain, known as ST6, to be from an Enterprise Foods production facility in Polokwane.

The plant was closed and Enterprise products were immediately pulled from shops nationwide. The plant would remain closed, Motsoaledi said on Monday.

Preliminary results also showed that several ready-to-eat processed meat products from the Enterprise facility located in Germiston contained listeria monocytogenes.

An investigation of the Rainbow Chicken Wolwehoek production facility was also done after polony products tested positive for listeria monocytogenes, but they were not the ST6 strain.

Products from these facilities were also recalled.

Three more people died shortly after the announcement, one a baby younger than one month.

Motsoaledi said on Monday that 5 812 tons of ready-to-eat processed meat had been recalled and that the total cost of containing the outbreak had come to R12m.

"No cases of listeria, due to the outbreak strain, have been identified since the first week of June 2018," the minister said.

"Therefore, the conclusion is that the outbreak of listeriosis in South Africa is over. I'm here to announce to you officially that we no longer have a listeria outbreak in South Africa."

According to the World Health Organisation, this outbreak was the largest recorded globally to date.