--- title: 10 Common Questions About Listeria and Their Answers date: 2022-12-11T00:43:00-08:00 author: Julie Dueck canonical_url: "https://marlerclark.com/news_events/10-common-questions-about-listeria-and-their-answers" section: News --- [All News](/news_events) / [Case News](https://marlerclark.com/news_events/case-news) / # 10 Common Questions About Listeria and Their Answers - **What is Listeria?** Listeria (pronounced liss-STEER-ē-uh) is a gram-positive rod-shaped bacterium that can grow under either anaerobic (without oxygen) or aerobic (with oxygen) conditions. Of the six species of Listeria, only L. monocytogenes (pronounced maw-NO-site-aw-JUH-neez) causes disease in humans. These bacteria multiply best at 86-98.6 degrees F (30-37 degrees C), but also multiply better than all other bacteria at refrigerator temperatures, something that allows temperature to be used as a means of differentiating Listeria from other contaminating bacteria. - **Where is Listeria found?** Listeria is a common presence in nature, found widely in such places as water, soil, infected animals, human and animal feces, raw and treated sewage, leafy vegetables, effluent from poultry and meat processing facilities, decaying corn and soybeans, improperly fermented silage, and raw (unpasteurized) milk. Foods commonly identified as sources of Listeria infection include improperly pasteurized fluid milk, cheeses (particularly soft-ripened varieties, such as traditional Mexican cheeses, Camembert and ricotta), ice cream, raw vegetables, fermented raw-meat sausages, raw and cooked poultry, and cooked, ready-to-eat (RTE) sliced meats—often referred to as “deli meats”. One study found that, over a five-year period of testing, in multiple processing facilities, Listeria monocytogenes was isolated from 14% of 1,080 samples of smoked finfish and smoked shellfish. Ready-to-eats foods have been found to be a notable and consistent source of Listeria. - **What is the incidence of Listeria in the United States?** in the United States. \[10\] Such data revealed an incidence-rate of 0.27 cases per 100,000 persons, a decrease of 42% compared with 1996—1998. But, according to CDC’s Technical Information website, it is estimated that there are 1,600 cases of Listeria infection annually in the United States, based on data through 2008. - **How is Listeria transmitted?** Except for the transmission of mother to fetus, human-to-human transmission of Listeria is not known to occur. Infection is caused almost exclusively by the ingestion of the bacteria, most often through the consumption of contaminated food. - **What is the incubation period of Listeria?** The amount of time from infection to the onset of symptoms—typically referred to as the incubation period—can vary to a significant degree. Symptoms of Listeria infection can develop at any time from 2 to 70 days after eating contaminated food. - **Who is most susceptible to Listeria?** Pregnant women naturally have a depressed cell-mediated immune system. In addition, the immune systems of fetuses and newborns are very immature and are extremely susceptible to these types of infections. Other adults, especially transplant recipients and lymphoma patients, are given necessary therapies with the specific intent of depressing T-cells, and these individuals become especially susceptible to Listeria as well. - **What are the symptoms of Listeria?** When a person is infected and develops symptoms of Listeria infection, the resulting illness is called listeriosis. Only a small percentage of persons who ingest Listeria fall ill or develop symptoms. For those who do develop symptoms because of their infection, the resulting illness is either mild or quite severe—sometimes referred to as a “bimodal distribution of severity.” On the mild end of the spectrum, listeriosis usually consists of the sudden onset of fever, chills, severe headache, vomiting, and other influenza-type symptoms. Along these same lines, the CDC notes that infected individuals may develop fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. When present, the diarrhea usually lasts 1-4 days (with 42 hours being average), with 12 bowel movements per day at its worst. - **How is Listeria diagnosed?** Methods typically used to identify diarrhea-causing bacteria in stool cultures interfere or limit the growth of Listeria, making it less likely to be identified and isolated for further testing. On the other hand, routine methods are effective for isolating Listeria from spinal fluid, blood, and joint fluid. Magnetic-resonance imaging (MRI) is used to confirm or rule out brain or brain stem involvement. - **What are the complications of Listeria?** For those persons who suffer a Listeria infection that does not resolve on its own, the complications (or sequelae) can be many. The most common is septicemia (bacterial pathogens in the blood, also known as bacteremia), with meningitis being the second most common. \[4, 18\] Other complications can include inflammation of the brain or brain stem (encephalitis), brain abscess, inflammation of the heart-membrane (endocarditis), and localized infection, either internally or of the skin. Death is the most severe consequence of listeriosis, and it is tragically common. For example, based on 2009 FoodNet surveillance data**,** 89.2% of Listeria patients ended up in the hospital, the highest hospitalization rate for pathogenic bacterial infection. In persons 50 years of age and older, there was a 17.5% fatality rate—also the highest relative to other pathogens. - **What is the treatment for Listeria?** Invasive infections with Listeria can be treated with antibiotics. When infection occurs during pregnancy, antibiotics given promptly to the pregnant woman can often prevent infection of the fetus or newborn. Babies with listeriosis receive the same antibiotics as adults, although a combination of antibiotics is often used until physicians are certain of the diagnosis. ### Other Listeria Lawsuits [Kroger and Walmart Pasta Listeria Outbreak](https://marlerclark.com/kroger-and-walmart-pasta-listeria-outbreak) [Listeria Outbreak linked to Kroger and Walmart Chicken Fettuccine](https://marlerclark.com/listeria-outbreak-linked-to-kroger-and-walmart-chicken-fettuccine) [Fresh & Ready Foods linked to California and Nevada Listeria Outbreak](https://marlerclark.com/fresh-ready-foods-linked-to-california-and-nevida-listeria-outbreak) [14 Listeria Deaths tied to Lyons ReadyCare or Sysco Shakes](https://marlerclark.com/11-listeria-deaths-tied-to-lyons-readycare-or-sysco) [Boar's Head Deli Meat Sickens 61 in 19 States with Deadly Listeria - 10 deaths](https://marlerclark.com/deli-meat-hits-28-in-12-states-with-deadly-listeria) [Rizo-López Foods recalls cheese after deadly Listeria Outbreak](https://marlerclark.com/rizo-l%C3%B3pez-foods-recalls-cheese-after-deadly-listeria-outbreak) [Listeria Outbreak linked to Peaches - 11 Sick with 1 Death](https://marlerclark.com/listeria-outbreak-linked-to-peaches-11-sick) [Listeria Outbreak linked to Frugals | Marler Clark by retained three victims](https://marlerclark.com/listeria-outbreak-announced-in-washington) [Six States Report 16 Victims of Listeria Linked to Deli Meat and Cheeses](https://marlerclark.com/six-states-report-victims-of-listeria-outbreak-linked-to-deli-meat-and-cheeses) [Big Olaf Ice Cream Sickens 28 in Florida Listeria Outbreak | 27 hospitalized, with 1 death](https://marlerclark.com/investigation-of-listeria-outbreak-linked-to-florida-residents-and-tourists) [Dole salads likely linked to Listeria illnesses since 2014](https://marlerclark.com/dole-salads-likely-linked-to-listeria-illnesses-since-2014) [Listeria Outbreak linked to Fresh Express Salads](https://marlerclark.com/listeria-outbreak-linked-to-fresh-express-salads) ### Lawsuit updates about foodborne illnesses [Reactive Arthritis Lawsuit Updates](/news_events/case-news?illness=reactive-arthritis&year=all) [E. coli Lawsuit Updates](/news_events/case-news?illness=e-coli&year=all) [Guillain-Barre Syndrome Lawsuit Updates](/news_events/case-news?illness=guillain-barre-syndrome&year=all) [Salmonella Lawsuit Updates](/news_events/case-news?illness=salmonella&year=all) [Hemolytic Uremic Syndrome Lawsuit Updates](/news_events/case-news?illness=hemolytic-uremic-syndrome&year=all) [Listeria Lawsuit Updates](/news_events/case-news?illness=listeria&year=all) [Irritable Bowel Syndrome Lawsuit Updates](/news_events/case-news?illness=irritable-bowel-syndrome&year=all) [Hepatitis A Lawsuit Updates](/news_events/case-news?illness=hepatitis-a&year=all) [Norovirus Lawsuit Updates](/news_events/case-news?illness=norovirus&year=all) [Botulism Lawsuit Updates](/news_events/case-news?illness=botulism&year=all) [Campylobacter Lawsuit Updates](/news_events/case-news?illness=campylobacter&year=all) [Shigella Lawsuit Updates](/news_events/case-news?illness=shigella&year=all) [Cyclospora Lawsuit Updates](/news_events/case-news?illness=cyclospora&year=all) ### Lawsuits updates by year [Foodborne Illness Lawsuits in 1998](https://marlerclark.com/news_events/case-news?illness=all&year=1998) [Foodborne Illness Lawsuits in 1999](https://marlerclark.com/news_events/case-news?illness=all&year=1999) [Foodborne Illness Lawsuits in 2000](https://marlerclark.com/news_events/case-news?illness=all&year=2000) [Foodborne Illness Lawsuits in 2001](https://marlerclark.com/news_events/case-news?illness=all&year=2001) [Foodborne Illness Lawsuits in 2002](https://marlerclark.com/news_events/case-news?illness=all&year=2002) [Foodborne Illness Lawsuits in 2003](https://marlerclark.com/news_events/case-news?illness=all&year=2003) [Foodborne Illness Lawsuits in 2004](https://marlerclark.com/news_events/case-news?illness=all&year=2004) [Foodborne Illness Lawsuits in 2005](https://marlerclark.com/news_events/case-news?illness=all&year=2005) [Foodborne Illness Lawsuits in 2006](https://marlerclark.com/news_events/case-news?illness=all&year=2006) [Foodborne Illness Lawsuits in 2007](https://marlerclark.com/news_events/case-news?illness=all&year=2007) [Foodborne Illness Lawsuits in 2008](https://marlerclark.com/news_events/case-news?illness=all&year=2008) [Foodborne Illness Lawsuits in 2009](https://marlerclark.com/news_events/case-news?illness=all&year=2009) [Foodborne Illness Lawsuits in 2010](https://marlerclark.com/news_events/case-news?illness=all&year=2010) [Foodborne Illness Lawsuits in 2011](https://marlerclark.com/news_events/case-news?illness=all&year=2011) [Foodborne Illness Lawsuits in 2012](https://marlerclark.com/news_events/case-news?illness=all&year=2012) [Foodborne Illness Lawsuits in 2013](https://marlerclark.com/news_events/case-news?illness=all&year=2013) [Foodborne Illness Lawsuits in 2014](https://marlerclark.com/news_events/case-news?illness=all&year=2014) [Foodborne Illness Lawsuits in 2015](https://marlerclark.com/news_events/case-news?illness=all&year=2015) [Foodborne Illness Lawsuits in 2016](https://marlerclark.com/news_events/case-news?illness=all&year=2016) [Foodborne Illness Lawsuits in 2017](https://marlerclark.com/news_events/case-news?illness=all&year=2017) [Foodborne Illness Lawsuits in 2018](https://marlerclark.com/news_events/case-news?illness=all&year=2018) [Foodborne Illness Lawsuits in 2019](https://marlerclark.com/news_events/case-news?illness=all&year=2019) [Foodborne Illness Lawsuits in 2020](https://marlerclark.com/news_events/case-news?illness=all&year=2020) [Foodborne Illness Lawsuits in 2021](https://marlerclark.com/news_events/case-news?illness=all&year=2021) [Foodborne Illness Lawsuits in 2022](https://marlerclark.com/news_events/case-news?illness=all&year=2022) [Foodborne Illness Lawsuits in 2023](https://marlerclark.com/news_events/case-news?illness=all&year=2023) [Foodborne Illness Lawsuits in 2024](https://marlerclark.com/news_events/case-news?illness=all&year=2024) [Foodborne Illness Lawsuits in 2025](https://marlerclark.com/news_events/case-news?illness=all&year=2025) [Foodborne Illness Lawsuits in 2026](https://marlerclark.com/news_events/case-news?illness=all&year=2026) ##### Get Help #### Affected by an outbreak or recall? The team at Marler Clark is here to answer all your questions. Find out if you’re eligible for a lawsuit, what questions to ask your doctor, and more. [ Get a free consultation ](https://marlerclark.com/contact) ##### Related Resources ###### [Listeria Food Poisoning](https://marlerclark.com/foodborne-illnesses/listeria/about-listeria) What is Listeria and how does it cause food poisoning? Listeria is a gram-positive, rod-shaped bacterium that is ubiquitous and can grow under either anaerobic (without oxygen) or aerobic (with... ###### [The Incidence of Listeria Infections](https://marlerclark.com/foodborne-illnesses/listeria/the-incidence-of-listeria-infections) How common are Listeria infections? Listeria bacteria are found widely in the environment in soil, including in decaying vegetation and water, and may be part of the fecal flora of... ###### [The Prevalence of Listeria in Food and the Environment](https://marlerclark.com/foodborne-illnesses/listeria/listeria-prevalence) Listeria bacteria are common in nature. Listeria monocytogenes is omnipresent in nature; it is found widely in such places as water, soil, infected animals, human and animal feces, raw and... ###### [Transmission of and Infection with Listeria](https://marlerclark.com/foodborne-illnesses/listeria/transmission-of-and-infection-with-listeria) Listeria typically spreads to people through contaminated food or water, but can also be transmitted from mother to fetus. Except for the transmission of mother to fetus, human-to-human transmission of... ###### [Who is Most at Risk of Becoming Ill with Listeria?](https://marlerclark.com/foodborne-illnesses/listeria/who-is-most-at-risk-for-becoming-ill-with-listeria) The elderly, pregnant women, and anyone immunocompromised is most at risk for contracting Listeria. Several segments of the population are at increased risk and need to be informed so that... ##### Outbreak Database #### Looking for a comprehensive list of outbreaks? The team at Marler Clark is here to answer all your questions. Find out if you’re eligible for a lawsuit, what questions to ask your doctor, and more. [ View Outbreak Database ](https://outbreakdatabase.com)