Listeriosis is a bacterial infection most commonly caused by Listeria monocytogenes, although L. ivanovii and L. grayi have been reported in certain cases. Listeriosis can cause severe illness, including severe sepsis, meningitis, or encephalitis, sometimes resulting in lifelong harm and even death. Those at risk of severe illness are the elderly,  fetuses, newborns and those who are immunocompromised. In pregnant women it may cause stillbirth or spontaneous abortion, and preterm birth is common. Listeriosis may cause mild, self-limiting gastroenteritis and fever in anyone.Listeria is ubiquitous and is primarily transmitted via the oral route after ingestion of contaminated food products, after which the bacteria penetrates the intestinal tract to cause systemic infections. The diagnosis of listeriosis requires the isolation of the causative bacteria from the blood and/or the cerebrospinal fluid. Treatment includes prolonged administration of antibiotics, primarily ampicillin and gentamicin, to which the organism is usually susceptible. Signs and symptoms
The disease primarily affects older adults, persons with weakened immune systems, pregnant women, and newborns. Rarely, people without these risk factors can also be affected. A person with listeriosis usually has fever and muscle aches, often preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has invasive infection (meaning that the bacteria spread from their intestines to their bloodstream or other body sites). Disease may occur as much as two months after eating contaminated food.The symptoms vary with the infected person:
High-risk people other than pregnant women: Symptoms can include fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions.
The joint investigation found that certain Blue Bell Creameries ice cream products, including bars, scoops and cookies, were the likely source for some or all of these illnesses. Upon further investigation the CDC said Blue Bell ice cream had evidence of Listeria bacteria in its Oklahoma manufacturing plant as far back as March 2013. The outbreak led to 3 deaths in Kansas.Blue Bell was the nations third most popular ice cream brand. The items came from the companys production facility in Broken Arrow, Oklahoma . The CDC stated that all five of the sickened individuals, including the three older people who died, were receiving treatment at the same Kansas hospital before developing the listeriosis, suggesting their infections with the Listeria bacteria were nosocomial (acquired, while eating the products, in the hospital). Their pre-existing weakened conditions might help to explain the higher mortality rate in these cases (60%, versus the more normal 20–30%).On April 20, 2015, Blue Bell issued a voluntary recall of all its products, citing further internal testing that found Listeria monocytogenes in an additional half gallon of ice cream from the Brenham facility. 2015–18 European listeriosis outbreak
On 5 July 2018 the Manchester Evening News reported that at least four major supermarket retailers had issued major product recalls as a result of a large supplier confirming possible contamination of frozen vegetables sourced from Hungary.