Listeriosis Food Poisoning

What is listeriosis?

Listeriosis is a kind of food poisoning you can get from eating contaminated food. The infection affects mainly pregnant women, newborns, and adults with weakened immune systems. It’s becoming more widely known as a possible cause of widespread food poisoning outbreaks.

What is the cause?

The bacteria that cause the infection are called Listeria monocytogenes. The bacteria are in soil and some dairy products, such as raw, unpasteurized milk and soft cheeses made from raw milk. Vegetables can become contaminated by bacteria in the soil or in manure used as fertilizer. Animals can carry the bacteria without appearing to be sick. In many cases, the source of infection is not known.

Pregnant women are much more likely than other healthy adults to have listeriosis. Their newborns may be born with the infection. Newborns can get much sicker than their mothers.

What are the symptoms?

The most common symptoms are:

• fever
• muscle aches

Less common symptoms are:

• nausea
• diarrhea

If the infection spreads to the nervous system it can cause meningitis. Meningitis is an infection of the covering of the brain and spinal cord. Symptoms of meningitis are:

• headache
• stiff neck
• confusion
• loss of balance
• convulsions

Listeriosis can be hard to diagnose right away because the symptoms may not be noticed for a few weeks.

How is it diagnosed?

Your healthcare provider will review your symptoms and examine you. The fluid from parts of your body, such as the blood, spine, or joints, may be tested for bacteria. If you have skin sores, they will be checked for bacteria.

How is it treated?

Your healthcare provider may prescribe an antibiotic. Mild infections often get better even without an antibiotic. For a serious infection you may need to take antibiotic medicine for several weeks to make sure all of the bacteria are gone. It is important to take all of the medicine your provider prescribes. If you stop taking the medicine too soon, the infection may come back.

When infection occurs during pregnancy, antibiotics given promptly to the mother can often keep the baby from getting infected. If a baby does get infected at birth or soon afterward, the baby will usually need intravenous (IV) antibiotics.

How long will effects last?

The length of illness can vary greatly from person to person. Often the illness is brief and does not need any treatment. However, the infection sometimes causes severe illness, such as meningitis or a blood infection (sepsis). This is more likely in infants, older adults, and people with other serious medical problems.

Infected pregnant women may just have mild, flulike symptoms. However, infection in a pregnant woman can lead to early delivery, infection of the newborn, and death of the baby.

How can I take care of myself?

• Follow your healthcare provider's instructions.
• Rest and take acetaminophen or ibuprofen, as recommended by your provider, to relieve your symptoms.
• Call your healthcare provider right away if you develop symptoms such as a stiff neck or severe headache.
• Call your healthcare provider if:
  • Your temperature is 101.5°F (38.6°C) or higher.
  • Your symptoms are not better in 24 to 48 hours or they are getting worse.
• If you are pregnant and you have fever and muscle aches, call your healthcare provider.

How can I help prevent listeriosis?

• Wash raw vegetables thoroughly before eating them.
• Cook all meat thoroughly.
• Keep raw meats separate from all other foods.
• Avoid unpasteurized (raw) milk or foods made from raw milk.
• Wash your hands, knives, and cutting boards with soap after handling uncooked foods.

In addition, if you are pregnant or have a weakened immune system, you should:

• Avoid eating soft cheeses such as feta, Brie, Camembert, blue-veined, and Mexican-style cheese unless they are pasteurized. It’s OK to eat hard cheeses, processed cheeses, cream cheese, cottage cheese, and yogurt.
• Cook leftover foods or ready-to-eat foods, such as hot dogs, until they are steaming hot.
• Do not eat hot dogs, luncheon meats, or deli meats, unless they are reheated until steaming hot.