Listeria infection is a foodborne illness that can be very serious for pregnant women and people with impaired immune systems. Listeria infection is most commonly contracted by eating improperly processed deli meats and unpasteurized milk products.
Healthy people rarely become ill from listeria infection, but the disease can be fatal to unborn babies and newborns. People who have weakened immune systems are also at higher risk of life-threatening complications. Prompt antibiotic treatment can help curb the effects of listeria infection.
Listeria bacteria can survive refrigeration and even freezing. That's why people who are at higher risk for serious infections should avoid eating the types of food most likely to contain listeria bacteria.
If you develop a listeria infection, you may experience:
Symptoms may begin a few days after you've eaten contaminated food, but it may take as long as two months before the first signs and symptoms of infection begin.
If the listeria infection spreads to your nervous system, signs and symptoms may include:
Symptoms during pregnancy and for newborns
As in adults, the signs and symptoms of a listeria infection in a newborn can be subtle, but may include:
When to see a doctor
If you experience a high fever, severe headache, stiff neck, confusion or sensitivity to light, seek emergency care. These signs and symptoms may indicate bacterial meningitis, a life-threatening complication of a listeria infection.
Listeria bacteria can be found in soil, water and animal feces. Humans typically are infected by consuming:
Unborn babies can contract a listeria infection from the mother via the placenta. Breast-feeding is not considered a potential cause of infection.
Pregnant women and people who have weak immune systems are at highest risk of contracting a listeria infection.
Pregnant women and their babies
People who have weak immune systems
Most listeria infections are so mild they may go unnoticed. However, in some cases, a listeria infection can lead to life-threatening complications — including:
Complications of a listeria infection may be most severe for an unborn baby. Early in pregnancy, a listeria infection may lead to miscarriage. Later in pregnancy, a listeria infection may lead to stillbirth, premature birth or a potentially fatal infection in the baby after birth — even if the mother becomes only mildly ill.
Preparing for your appointment
If you have eaten food that has been recalled because of listeria contamination, you should see a doctor only if you are experiencing signs and symptoms of a listeria infection. However, if you're pregnant, you should see a doctor even if you aren't experiencing symptoms because of the danger to your unborn child.
What you can do
You might also want to write a food diary, listing all the foods you've eaten each day for as far back as you can reliably remember.
What to expect from your doctor
Tests and diagnosis
A blood test is often the most effective way to determine whether you have a listeria infection. In some cases, samples of urine or spinal fluid may be tested as well.
Treatments and drugs
Treatment of listeria infection varies, depending on the severity of the signs and symptoms. Most people with mild symptoms require no treatment. More serious infections can be treated with antibiotics. During pregnancy, prompt antibiotic treatment may help keep the infection from affecting the baby. Newborns who have a listeria infection may receive a combination of antibiotics.
To prevent a listeria infection, follow simple food safety guidelines:
Precautions for people particularly at risk
Last Updated: 2011-03-22
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