Listeriosis update |19 April 2018

South Africa

The listeriosis situation in South Africa is improving. Although cases are still being registered, these are diminishing since the source was identified as ready-to-eat processed meat products manufactured at Enterprise Foods’ Polokwane production facility.

The accompanying graph shows a rapid decline in the number of cases after the source of contamination was identified and product recall was instituted.

The recall of implicated food products was announced on March 4, 2018. However, it is expected that new outbreak-related cases will continue to be reported, for the following reasons:

• The incubation period of listeriosis can be up to 70 days and the implicated food products have a long refrigeration shelf life, and it is possible that despite the recall some products were not removed from retail/home settings, and consumption might occur.

• The possibility of cross-contamination of other types of foods in the retail or home setting may result in additional cases.

In total, South Africa has so far reported 999 confirmed laboratory cases with 191 deaths. The total number of unconfirmed cases is much higher.

Australia

Meanwhile, a separate report of listeriosis happened in Australia and it was linked to rock melon from a particular farm in New South Wale. All melons from the farm were recalled by the Australian authority, but not until it may have been exported, including to certain countries in the middle East from which supplier in Seychelles import. After receiving the report formally and later through the social media that the rock melon may have reached Seychelles, the Food control unit in Public Health Authority (PHA) in conjunction with biosecurity unit launched an investigation and product tracing. We have since found that rock melon from the farm in question was not re-exported to Seychelles. As a precaution test results of melon imported by the Seychelles importer coming from Australia were sought. They have all been negative for listeria; which means they do not carry the bacteria.

Information and other measures

The PHA continues its surveillance on the field, in health facilities and laboratory, and will update the media periodically.

Listeriosis is caused by the bacterium Listeria monocytogenes. It is transmitted to persons through contaminated food or water. Healthy persons exposed to Listeria do not fall ill. The vast majority of cases are mild, and the most common form of disease is an acute, self-limiting gastroenteritis which presents with fever and diarrhoea; this usually resolves on its own without medical intervention within a few days.

However, some infections are serious and persons may present with severe illness. Certain groups of people are more at risk of developing serious illness especially pregnant women, infants, elderly above 65 years and those with weak immune system.

Listeriosis is mainly associated with consumption of contaminated Ready-To-Eat foods. Foods most often implicated in foodborne outbreaks globally, are:

- Ready-to-eat deli meats (polonies, ham products etc) and hot dogs.

- Refrigerated pâtés or meat spreads

- Unpasteurized (raw) milk and dairy products

- Soft cheese made with unpasteurized milk, such as, Feta, Brie, Camembert

- Refrigerated smoked seafood

- Pre-packaged salads

Contributed by the Ministry of Health