Listeriosis is a serious infection caused by the bacteria Listeria monocytogenes. Listeria can infect the brain, the spinal cord membranes or the bloodstream.

Listeria can be found in water, soil and animals. Foodborne infections are often linked to contaminated vegetables, unpasteurized milk, soft cheeses or ready-to-eat meats.

Anyone can get the infection, but people who are elderly, pregnant, newborns or people with weakened immune systems are at increased risk of serious illness.


The most common symptoms of listeriosis can include fever, muscle aches, fatigue and diarrhea. In a more serious form of the infection, you may also experience intense headache, confusion, loss of balance and convulsions.

Symptoms usually appear about three weeks after exposure, but can range from three to 70 days.


  • Do not eat soft cheeses or dairy products that are unpasteurized.
  • Do not eat smoked fish, pâtés, or meat spreads. Make sure meat is thoroughly cooked before eating.
  • Reheat cold cuts (deli meats) before eating.
  • Wash your hands with soap and warm water before touching food or feeding infants, and after handling raw meat.

Risk in Pregnancy

Listeria infections are a significant risk during pregnancy. Infection of the fetus can occur before delivery and can cause premature delivery, miscarriage or stillbirth.

Diagnosis and Treatment

  • Your doctor can test your spinal fluid, blood, placenta or other sites to check for the bacteria.
  • Antibiotics are often used to treat the infection.

Additional Resources

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