Listeriosis, caused by the bacterium Listeria monocytogenes, is a serious illness that chiefly affects pregnant women, newborns, elderly persons, and others with compromised immune systems. The CDC (Center for Disease Control and Prevention) estimates that while there are only 2,500 cases a year, approximately 500 result in death.
Early symptoms, which usually appear within a month of exposure, typically include fever, muscle aches, and, in some cases, gastrointestinal troubles such as nausea and diarrhea. However, if the infection spreads to the nervous system, symptoms become more severe and may include headache, disorientation, stiff neck, inability to balance, and convulsions. While pregnant women may only experience mild symptoms, the effects of a Listeriosis infection during pregnancy can be devastating, including the possibility of miscarriage, premature delivery, stillbirth, the blood infection septicemia, and meningitis in the newborn child. Symptoms may appear as early as one week to as late as 90 days following the consumption of contaminated food or drink.
Listeria is primarily contracted by consuming contaminated food products. A child may be born with the illness if the mother ate contaminated food during pregnancy. The bacterium is not uncommon in nature, being found in dirt, water, and on plants and animals. Because of this, foods of animal origin, such as meat and dairy, are at risk for contamination. Primarily though infected animals, food processing facilities and their equipment can become contaminated. Foods associated with Listeria are uncooked meat, uncooked and smoked fish, uncooked vegetables, and processed foods, such as cheese, ice cream, and cold cuts. Non-pasteurized milk products are also potential carriers of the bacterium. Some foods, such as hotdogs, deli meats, and other ready-to-eat foods, may become contaminated after cooking but before they are packaged.
Diagnosis of listeriosis can be done by means of blood or spinal fluid tests. The blood test is most reliable during pregnancy. Those at a higher risk for infection (with compromised immune systems) should who develop symptoms of this serious disease within two months of eating potentially contaminated food should inform their doctor about the possible exposure to Listeria.
Treatment involves the prescription of antibiotics. If a pregnant woman who is infected takes antibiotics early enough in the infection, this can prevent the spread of the disease to the fetus. Babies are also treated with antibiotics. Those most at risk are elderly persons and those already suffering from serious medical conditions.
Means of preventing Listeria are similar to those of the prevention of other foodborne illnesses. They include properly and thoroughly cooking all meat products, washing raw vegetables before consumption, keeping raw meat separate from other food products, avoiding non-pasteurized drinks, washing hands following the preparation of food, and limiting the shelf life of perishable food items.
Pregnant women and those with compromised immune systems should be particularly careful. Additional means of prevention include not consuming hotdogs or deli meats unless they are reheated to a high temperature, ensuring that the fluid from hotdog packages does not contaminate other surfaces, washing hands after handling hotdogs or deli meats, not eating soft cheeses unless they have been pasteurized, not eating refrigerated pâtés or meat spreads, and not eating refrigerated, smoked seafood, unless it is contained in a cooked dish. While these may seem like extreme measures, they are recommended precautions if one wishes to drastically reduce the risk of contracting Listeria.