Fever, meningitis, miscarriages…: how listeriosis can turn a simple cheese into a potentially deadly poison

Behind the wave of cheese recalls that has rocked France in recent days, there is one culprit: Listeria monocytogenes . Invisible to the naked eye, this bacteria can nevertheless prove dangerous, particularly for pregnant women, the elderly, or the frail.

With 21 cases and two deaths reported since June, including a possible link to a cheese factory in Creuse , here's what you need to know to understand the risks - and protect yourself from them.

An omnipresent bacteria… but discreet

It's found everywhere: in soil, water, and animal excrement. In 99% of cases, contamination occurs through food. Cheese, cold meats, smoked fish, and even poorly washed raw vegetables can serve as a gateway.

A worrying feature: Listeria is resistant to the cold of domestic refrigerators and grows very well between 4°C and 30°C. Only high temperatures or thermal shocks can destroy it.

Three faces, three levels of seriousness

Listeriosis can manifest itself in very different forms. The most common is the digestive form , which is similar to gastroenteritis, with a short incubation period ranging from a few hours to a few days and, in a healthy adult, a generally benign course.

Rarer but much more serious, the invasive neuromeningeal form occurs when the bacteria passes into the blood and reaches the brain. It then causes a stiff neck, sensitivity to light, nausea, sometimes vomiting, and occurs on average ten days after infection: it is a life-threatening emergency .

Finally, the maternal-fetal form is the most feared. The risk is estimated to be seventeen times higher in pregnant women, with potentially dramatic consequences for the fetus, such as miscarriage , premature delivery or death in utero . Its incubation period can exceed twenty days, making medical monitoring essential in the event of suspected exposure.

Why you shouldn't take these reminders lightly

With the incubation period being up to 88 days in some cases, it is imperative to act as soon as a product is suspected. Even pasteurized cheese can be contaminated.

If you experience fever, headache, or body aches after consuming a recalled product, it is essential to consult a doctor promptly and mention the exposure.

The 21 cases reported by Public Health France since June are not isolated: listeriosis causes several dozen deaths in France each year.