Listeriosis can be a serious infection caused by the bacteria (germs) Listeria monocytogenes. Listeria may infect many different sites of the body, such as the brain or the spinal cord membranes, or the bloodstream. For data on listeriosis in New York City visit EpiQuery.
Anyone can get listeriosis, but those at highest risk are newborns, the elderly, people with weakened immune systems, and pregnant women. About 30 percent of cases occur in newborns within the first three weeks of life.
Listeria infections occur throughout the year. Although most cases occur sporadically, foodborne outbreaks do occur.
Listeria germs are widely distributed in nature and can be found in water, soil and animals. Foodborne infections are often associated with contaminated vegetables, unpasteurized milk, soft cheeses or ready-to-eat meats. In newborn infections, the organism may be transmitted from mother to fetus in utero, or during delivery.
Because listeriosis can affect many different parts of the body, the symptoms vary. In most cases, Listeria infection causes a nonspecific illness, with fever and influenza-like symptoms. In a more serious form of the infection, known as meningoencephalitis, the onset can be sudden fever, intense headache, nausea, and vomiting.
Listeria infections are a significant risk for pregnant women, who often do not have symptoms. Infection of the fetus can occur before delivery and can cause abortion as early as the second month of pregnancy, but more often in the fifth and sixth months. An infection later in pregnancy may result in infection of the newborn, which can be fatal.
The symptoms usually appear about 3 weeks after exposure, but can range from 3 to 70 days.
If a doctor suspects Listeriosis, he/she can test the spinal fluid, blood, placenta, or other sites of infection to check for the bacteria. Does past infection with Listeria make a person immune? Past infection appears to produce some protective immunity.
Several antibiotics are effective for treating listeriosis. Ampicillin, either alone or in combination with other antibiotics, is frequently used.
Since Listeria is widespread in nature, basic sanitary measures offer the best protection.
Last Updated: March 2012