LISTERIOSIS UPDATE

We keep hearing about the outbreak of Listeria monocytogenes – how worried should we be?

What you need to know. Plus 8 ways to avoid it

AM I AT RISK?

That depends. You don’t need to be a particular physical type to get it – anyone can, from newborns to healthy (or previously healthy!) adults. But it’s worth noting that most of the 748 laboratory-confirmed cases are people who already had some kind of underlying immune supression like HIV, cancer, chronic kidney or liver disease, or those on prolonged steroid therapy, or organ transplant recipients.

Having said that, if you’re pregnant you need to be careful, especially if you’re in your third trimester, because it can affect newborns and there is a possibility of complications if the central nervous system (brain or spinal cord) gets involved. You’ll probably feel as if you have flu, but with backache too. Don’t worry: it’s most often very mild and can easily be fixed, but if you have diarrhoea that just doesn’t seem to get better, best you see your doctor for a stool and blood culture.

ANY SYMPTOMS I SHOULD LOOK OUT FOR?

Symptoms vary depending on which system is involved – your brain, spinal cord, blood stream or your digestive system. But you may notice any or all of these: watery stools, fever, headache, dizziness, nausea, vomiting, generalized malaise, your joints and muscles will ache, you may have a stiff neck, feel confused or even, in a bad case, have a seizure. These symptoms usually last up to 48 hours, and then you simply recover from them.

There is a very tiny possibility of complications like meningitis, encephalitis, endocarditis, septicaemia, brain abcess and so on, but it’s very rare and unlikely if you’re healthy.

WHAT CAUSES IT?

Genetic testing has identified a single strain of the bacteria, sequence type 6 (ST6), that seems to be causing the majority of infections. It’s most often found in soil, vegetation, water and faeces, but it’s extremely difficult to find the actual source and eliminate it, which would obviously be the best solution. This particular outbreak is most likely from ‘a food product on the market or a series of food products produced in the same manufacturing environment’‚ says South African food microbiologist and food safety expert Dr Lucia Anelich, but ‘as things stand‚ the source is still not known’.

IS LISTERIOSIS CONTAGIOUS?

No. It can’t be transmitted from person to person. You’ll get it from drinking contaminated water, or eating contaminated food. Although it tends to thrive in summer, the latest studies have shown that listeria actually accounts for less than one percent of reported cases of bacterial food-borne infections.

HOW IS IT DIAGNOSED?

The diagnosis is confirmed by the results of a blood culture or from fluid taken from the central nervous system via a lumbar puncture. Listeriosis is now a notifiable disease, which means all healthcare workers are legally obliged to report all new cases to the Department of Health. This, of course, helps with tracing the source of the infection.

WHAT’S THE TREATMENT?

Fortunately, healthy people may not require any treatment – listeriosis usually resolves itself within a couple of days. Some people may need antibiotics, but the treatment varies from patient to patient and depends on other factors too, like your underlying health, for instance.

SOME GOOD NEWS

Finally, it’s important to remember that even though the numbers look bad, most people with no underlying ill-health get better on their own, or with minimal treatment. But if you’re in any doubt, err on the side of caution and contact your nearest health care practitioner.