Most people become sick 28-30 days after they have been exposed to a contaminated product. Some people may not show symptoms until up to 70 days after they were first exposed to the bacteria. Common symptoms are dependent on whether the person is pregnant. These symptoms include the following:

• Fever
• Muscle aches
• Fatigue
• Headache
• Stiff neck
• Confusion
• Loss of balance
• Convulsions
• Diarrhea
• Vomiting

Some people never have symptoms, while some may have more severe symptoms. Almost one in six people who are not pregnant but have invasive listeriosis die. Those who have listeria while pregnant are at risk of more severe outcomes. Complications from listeriosis while pregnant may occur, such as miscarriage, stillbirth, and premature delivery. Unfortunately, approximately 25 percent of women may lose their pregnancy, or their baby after birth.

Diagnosis

Listeriosis is usually diagnosed through laboratory testing of body tissue or fluid, blood, spinal fluid, or the placenta in pregnancy-associated cases.

Treatment

Listeriosis is often a severe condition and requires treatment. Listeriosis is usually treated with antibiotics.

Practice good hand hygiene and use good handwashing techniques

• Wash your hands thoroughly for 20 seconds with soap and running water, especially after using the restroom, swimming, contact with animals, and before preparing food

Practice proper food safety

• Use a food thermometer to be sure food is cooked to its proper temperature
• When in doubt, throw the food out
• Thaw or marinate foods in the refrigerator, and never on the counter or the kitchen sink
• Always remember to store, clean, and prepare fruits and vegetables properly
• Keep raw meat separate from fresh produce and other ready-to-eat food to avoid cross-contamination
• Use a thermometer to ensure the refrigerator is 40°F or lower and the freezer is 0°F or lower

Foods to avoid during pregnancy

• Uncooked eggs
• Unpasteurized cheese
• Liver
• Deli meat
• Sprouts
• Cold smoked fish
• Raw or undercooked meat
• Raw shellfish
• Prepackaged salads and sliced fruit

Once you or your child start having symptoms of the illness, such as diarrhea, do not attend work (specifically for food handlers, healthcare workers, daycare workers) or attend daycare or school until a healthcare provider or someone from your local health department says you are clear to go back.

If you believe you have listeriosis and have not yet been treated or spoken to a doctor, please be sure to do so. You should be evaluated by a doctor to confirm that you have listeriosis, and that you get the correct treatment. You should also respond to requests to be interviewed by your local or state public health department. An investigation will take place for every confirmed case of listeriosis. It is important that you answer the call from your local or state health department so that other people in your home or near you are not at risk of getting listeriosis as well. An investigation may also look into your exposures to check if other people are at risk.