The Center for Disease Control and Prevention (CDC) has issued an investigation notice into a Listeria outbreak in Florida. This outbreak has so far caused 22 hospitalizations and one death. No specific food item has been identified as the source and most people who fell ill lived in or traveled to Florida a month before they got sick.

The illness was first reported on January 24, 2021, through to June 12, 2022. It is thought that the true number of people who have been infected is a lot higher, and any recent cases may not yet be recorded due to the potentially long incubation time and the time it takes to identify when people are part of the outbreak.  

So, what is Listeria?

Listeria infection is caused by a germ called Listeria monocytogenes, and people often get sick within two weeks of eating food contaminated with the bacteria. For this outbreak, it is unclear whether there is a specific food item that is linked to these cases.

The people at risk for this disease are pregnant people and their newborns, people with weakened immune systems, and adults aged 65 or older. Other people are at risk and can become infected, but it is rare that they will get seriously ill. 

For this outbreak: “Five people got sick during their pregnancy, and one illness resulted in a fetal loss,” the CDC said on its website.

For people who are pregnant, Listeria infection symptoms can include muscle aches, fever, and fatigue, but during pregnancy, it can also cause premature delivery, miscarriage, and life-threatening infections in newborns. Listeriosis during pregnancy can cause fetal losses in 20 percent of cases and newborn death in 3 percent of cases.

For people who are not pregnant, the infection can cause confusion, loss of balance, headaches, fever, muscle aches, and stiff necks.

It can also cause symptoms more attributed to common food poisoning, like fever and diarrhea. All these symptoms normally start two weeks after eating contaminated food, but sometimes can begin the same day or as late as 70 days.

If anyone gets these symptoms, the CDC is recommending that you write down everything you can remember of what you ate and where in the month before you got ill, along with answering any questions that public health officials may have about the illness. This key information may help solve the cause of the outbreak.

To prevent this disease, it is important to stay up to date on any food recall and avoid those that are more likely to contain Listeria. Many foods can be contaminated with this bacteria, but it is usually found in ready-to-eat chilled food like pre-prepared sandwiches and salads, smoked fish and cooked shellfish, cooked sliced meats and cured meats, blue vein and mold-ripened soft cheeses, some pre-prepared fruit, unpasteurised milk and dairy products made from it, and pâté.

This infection is normally diagnosed when a sample of body tissue or fluid (i.e., placenta, blood, or spinal fluid) grows a bacterial culture of the bacteria in laboratory conditions. It can normally be treated with antibiotics.

Anyone who thinks that they have eaten contaminated food or have begun to exhibit the symptoms should seek help from a medical provider, especially those at risk.