At least 23 people have gotten sick from listeria, a bacteria that can cause severe illness and pregnancy loss, according to the US Centers for Disease Control and Prevention.
The infection known as listeriosis typically affects people who have consumed contaminated food, but no specific food item has been linked to the outbreak so far, the agency said in an investigation notice Thursday.
All but one of the people infected have been hospitalized, and one individual from Illinois has died of the illness. Of those infected, five people were pregnant at the time and one of them had a miscarriage.
Pregnant people and newborn babies have an especially high risk of getting severely ill if infected with listeria. Symptoms typically include fever, fatigue, and muscle aches; however, infection during pregnancy can lead to miscarriage, stillbirth, or premature delivery.
People with compromised immune systems and adults older than 65 are also considered high-risk for severe listeria infection, according to the CDC.
Other symptoms of listeria infection include headache, stiff neck, confusion, loss of balance, and convulsions – which indicate the infection has traveled from the gut to the brain. Symptoms may occur more than two months after exposure to contaminated food or water.
“Part of the problem is listeria has an incubation period of three to 70 days,” food safety attorney Bill Marler told Insider. “You’d have to ask people what they ate for the last 60 days, so it can be hard to track down what it is unless they got sick quickly.”
Immunocompromised or pregnant people may show symptoms of listeria infection sooner than people with normal immune function, Marler said, so cases in a related outbreak can occur over a few months.
The cases were reported from 10 different states, but nearly all of the people who got sick either live in or recently traveled to Florida, the CDC reported. The significance of the link to Florida is not yet known. In the meantime, the agency has recommended that people who have recently traveled there take extra care if they develop symptoms of listeriosis.