Picture: ISTOCK
Picture: ISTOCK

The death toll in SA’s listeriosis outbreak has climbed to 172, the National Institute for Communicable Diseases (NICD) said on Thursday. It is the worst outbreak recorded in SA, and its source still remains a mystery, hampering efforts to prevent more cases.

A total of 915 laboratory-confirmed cases of listeriosis have been reported to the NICD since January 2017.

The NICD said 59% of the reported cases were in Gauteng, while the Western Cape and KwaZulu-Natal accounted for 12% and 7%, respectively.

Listeriosis is caused by a common bacterium, listeria, which is found in soil, water, plants and in the faeces of some animals. The fact that it has a variable incubation period, ranging from between six hours and 70 days, and can contaminate a wide variety of foodstuffs, makes determining the source of the outbreak particularly challenging, the NICD said.

"Various stakeholders, including numerous government departments, the healthcare sector, the veterinary public health sector, and the food industry are working around the clock to find the source of the outbreak. Specialised tests are being conducted by experts at the NICD laboratories to assist in detecting the source as soon as possible," it said.

The NICD said pregnant women, the elderly and people with a weakened immune system were at increased risk from listeria. It advised them to steer clear of food that was commonly linked to listeriosis, including processed meat, soft cheese and unpasteurised milk and dairy products.

Listeriosis can cause flu-like symptoms, stiff neck, confusion and convulsions, and is sometimes accompanied by diarrhoea or vomiting. In pregnant women, it can cause stillbirths, miscarriages or premature delivery, or life-threatening infections of their newborn babies. It is treated with antibiotics.