Listeria monocytogenes - the bacteria that leads to cases of Listeriosis - Photo by CDC
Speaking at a press conference with the National Institute for Communicable Diseases (NICD) on Tuesday morning, Minister of Health Aaron Motsoaledi told reporters that they had confirmed 557 cases of Listeriosis within South Africa. Within this number the national Department of Health had tracked 70 cases, of which 36 were confirmed to have died.
South Africa typically experiences between 70 and 80 cases of Listeriosis each year, and the cause of the recent spike in infections has not yet been identified. Of the infections in the current outbreak, 62% are located in Gauteng, with 13% in the Western Cape, 7% in Kwazulu-Natal, and the remainder spread across South Africa. Motsoaledi said that because the range of infected food crossed class boundaries, the source of the infection could well be high up the food supply chain at a processing plant or farm.
What is Listeriosis?
Listeriosis is a bacterial infection that is primarily transmitted through ingestion of contaminated food products. The bacteria then penetrates through the intestinal tract, producing an invasive infection in other systems of the body. Most at risk from the bacteria are pregnant women, newborns, persons with compromised immune systems and the elderly.
In pregnant women symptoms manifest similar to a mild flu. However the infection can have disastrous consequences for the baby, resulting in premature delivery and potentially life-threatening infection for the newborn. Often the baby is at risk of being miscarried or stillborn. In vulnerable persons, other than pregnant women, infections can result in fever, aches, headaches, stiff necks, disorientation and diarrhoea.
Once contaminated food has been consumed it can take as much as two months for symptoms of Listeriosis to emerge. Diagnosis can be challenging, as early symptoms often appear similar to other gastrointestinal infections. An accurate diagnosis can be made by isolating the bacteria in a sample of blood, or spinal and amniotic fluid, or a sample of the placenta.
The disease has a mortality rate of between 20% and 30%. Pregnant women are ten times more likely to develop a Listeriosis infection than average. Serious infections can be treated with antibiotics, and if caught quickly antibiotics may stop the infection from spreading to the pregnancy.
How can I prevent Listeriosis?
The United States Center for Disease Control and Prevention makes several simple recommendations for preventing Listeriosis. They recommend rinsing all fruit and vegetables that are being consumed raw. Raw foods and cooked foods should be kept separate during preparation, with food being cooked thoroughly or reheated at a high temperature. Anything that comes into contact with juices from raw, and even prepackaged foods should be thoroughly washed and cleaned. Unpasteurised or raw milk should be avoided completely.
For persons at high risk it is recommended that they completely avoid foods such as hot dogs and cold cuts, refrigerated meat or pâté spreads, and soft cheeses unless they are labelled as being made with pasteurised milk.
If a person is not showing symptoms, it is generally accepted that they do not need to undergo testing. If a person is showing symptoms they should immediately consult a medical professional.
Listeriosis in South Africa
In September 2017 the NICD released a report titled “Unprecedented increase of listeriosis”, which showed a remarkable increase in the incidence of Listeriosis being reported in South Africa. Starting in October 2016 the incidence of Listeriosis in the population began skyrocketing, with the largest rise being reported in the City of Johannesburg Metro area. At the time of the report the NICD reported 190 confirmed cases, implying that the number of confirmed cases has tripled in the past four months.
During Tuesday's press conference, Dr Juno Thomas, head of the Centre for Enteric Diseases at the NICD, told reporters that the death toll would rise as better data was generated on the reported cases.
The Listeriosis guidelines released by the NICD - Photo NICD