Health authorities are investigating a new outbreak of the potentially fatal foodborne bacteria Listeria monocytogenes, but have not yet identified its source.
The Food and Drug Administration said Friday that 11 people have fallen ill in connection with the outbreak.
Investigators have so far been unable to determine where or how those patients were exposed.
The FDA has released no additional details, including the patients’ locations or ages. Because the source remains unknown, people across the United States could potentially be at risk.
Listeria is a leading cause of severe foodborne illness in the US. Symptoms may include diarrhea, vomiting, fever and chills resembling the flu. In more serious infections, the bacteria can enter the bloodstream and trigger sepsis, a potentially life-threatening condition.
The FDA has not announced a recall connected to the outbreak.
Officials have also issued no guidance on specific foods or products to avoid. During previous listeria investigations, however, consumers were advised to thoroughly clean and sanitize surfaces, utensils and containers that could be contaminated.
Consumers have also been urged to cook food thoroughly before eating it. Listeria cannot survive temperatures above 149F (65C).
Health officials are probing a new outbreak of the potentially deadly foodborne bacteria listeria
The outbreak appeared in the FDA’s latest online update on ongoing foodborne illness investigations, although the agency has not issued a public alert.
The agency said it has started tracing the illnesses and interviewing patients as investigators work to identify a possible common source.
Recent FDA data show that three listeria outbreaks are currently active.
The latest investigation follows a separate active listeria outbreak disclosed on September 23 that has sickened 44 people.
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Another outbreak, reported July 22, has also affected 11 people and remains under investigation. The FDA has not identified its source.
Officials cautioned that the confirmed figures may represent only a fraction of the true number of illnesses. They estimate that for every documented outbreak case, roughly 29 additional cases go unrecorded.
The Daily Mail contacted the FDA seeking further information.
Listeria naturally occurs in damp environments, including soil, water, decaying plant matter and animals. Unlike many bacteria, it can survive refrigeration and other food-preservation methods.
Potential sources include unpasteurized milk, soft cheeses and ready-to-eat products such as packaged sandwiches.
Cooked shellfish, cured meat and fish—including sushi—as well as pre-cut fruit can also carry the bacteria.
An estimated 1,250 Americans contract listeria infections each year, while approximately 250 die from the disease, according to available data.
For most healthy people, a Listeria infection causes mild intestinal illness and they can recover on their own without antibiotics.
However, if the bacteria spread beyond the gut, the infection can become far more serious, causing fever, muscle aches, headache, stiff neck, confusion, loss of balance and seizures, sometimes following diarrhea or other gastrointestinal symptoms.
Those with invasive listeriosis generally require antibiotic treatment and hospitalization, with older adults, pregnant women, newborns and people with weakened immune systems at greatest risk of severe illness.
The CDC estimates that about one in five people with listeriosis die from the infection, making it one of the deadliest foodborne illnesses in the US
Pregnant women, elderly people and those with compromised immune systems are most at risk for contracting this bacteria. It can also cause miscarriages and stillbirths among pregnant women.
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