Type: Bacterial

Geography: Worldwide

Cases Per Year: 700 to 80,000

Fatality Rate: 15% to 20%

First Discovered: 1927 by E.G.D. Murray and J. Pirie

Foodborne listeriosis is one of the most serious and severe foodborne diseases. The main route of infection is eating contaminated food with high numbers of Listeria monocytogenes. Infection can also be transmitted from pregnant women to unborn babies. High risk foods include deli meat and ready-to-eat meat products, soft cheeses, cold smoked fishery products, and prepared salads.

Non-invasive listeriosis is a mild form of the disease that mainly affects otherwise health people. Symptoms include diarrhea, fever, headache, and muscle pain. The incubation period lasts a few days. Invasive listeriosis is a more severe form of the disease and affects high risk groups such as pregnant women, the elderly, individuals with weakened immune systems, and infants. The mortality rate of severe listeria is 20% to 30%. These symptoms include fever, muscle pain, septicemia, and meningitis. The incubation is usually 1 to 2 weeks but can last up to 90 days.

To prevent listeriosis, people should practice safe food handling. When diagnosed early, listeriosis can be easily treated. Antibiotics are used in the case of severe symptoms.

Photo: Listeria monocytogenes – Electron micrograph.