--- title: The Incidence of Listeria Infections date: 2012-07-12T15:38:00-07:00 author: admin canonical_url: "https://marlerclark.com/foodborne-illnesses/listeria/the-incidence-of-listeria-infections" section: Resource Library --- [Foodborne Illnesses](/foodborne-illnesses) / [Listeria](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 a large number of mammals, including healthy human adults. [![](https://s3.us-west-2.amazonaws.com/aboutlisteriacom-images/outbreaks/image2.jpeg?1615534777161)](https://www.slideshare.net/OussaJaz/listeria-monocytogenes-a-multipotent-bacterium)According to the United States Food and Drug Administration (FDA), some healthy adults may be asymptomatic intestinal carriers of the bacteria. Another authority notes that the “organism has been isolated from the stool of approximately 5% of healthy adults.” According to the Centers for Disease Control and Prevention’s (CDC) National Center for Zoonotic, Vector-Borne, and Enteric Diseases, listeriosis was added to the list of nationally notifiable diseases in 2001: > To improve surveillance, the Council of State and Territorial Epidemiologists has recommended that all *L. monocytogenes* isolates be forwarded to state public health laboratories for subtyping through the National Molecular Subtyping Network for Foodborne Disease Surveillance (PulseNet). All states have regulations requiring health care providers to report listeriosis cases, and public health officials should try to interview all persons with listeriosis promptly using a standard questionnaire about high risk foods. To reach this goal, FoodNet conducts active laboratory- and population-based surveillance. The following table shows selected data from the CDC’s Annual Surveillance Summaries of reported *Listeria* cases. Increases over time could be explained in part by increased surveillance and reporting. **Table 1.** Selected data from the CDC’s Annual Surveillance Summaries of reported *Listeria* cases ![](https://s3.us-west-2.amazonaws.com/aboutlisteriacom-images/outbreaks/Screen-Shot-2021-01-03-at-3.27.21-PM.png)Despite these numbers, CDC’s Technical Information website estimates that there were more than 1,600 cases of *Listeria* infection annually in the United States based on data through 2008. Although the nature and degree of underreporting is subject to dispute, all sources agree that the confirmed cases represent just the tip of the iceberg. The *Listeria* Initiative and PulseNet conduct nationwide surveillance to rapidly detect and respond to outbreaks; the Foodborne Diseases Active Surveillance Network (FoodNet) conducts active, sentinel population-based surveillance to track incidence trends; and the Foodborne Disease Outbreak Surveillance System (FDOSS) receives reports of investigated outbreaks to track foods and settings associated with outbreaks. In a CDC report summarizing data on 2009-2011 listeriosis cases and outbreaks reported to U.S. surveillance systems: > Nationwide, 1,651 cases of listeriosis occurring during 2009–2011 were reported. The case-fatality rate was 21%. Most cases occurred among adults aged ≥65 years (950 \[58%\]), and 14% (227) were pregnancy-associated. At least 74% of nonpregnant patients aged <65 years had an immunocompromising condition, most commonly immunosuppressive therapy or malignancy. The average annual incidence was 0.29 cases per 100,000 population. Compared with the overall population, incidence was markedly higher among adults aged ≥65 years (1.3; relative rate \[RR\]: 4.4) and pregnant women (3.0; RR: 10.1). Twelve reported outbreaks affected 224 patients in 38 states. Five outbreak investigations implicated soft cheeses made from pasteurized milk that were likely contaminated during cheese-making (four implicated Mexican-style cheese, and one implicated two other types of cheese). Two outbreaks were linked to raw produce. [ Next: The Prevalence of Listeria in Food and the Environment › ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-prevalence) ### More information about Listeria [August 23, 2023 ###### Listeria outbreak: Three die after drinking contaminated milkshakes Three people have died, and three others are in hospital after drinking milkshakes contaminated with listeria bacteria in the US state of Washington, health officials say. Marler Clark, the Listeria ... ](https://marlerclark.com/news_events/listeria-outbreak-three-die-after-drinking-contaminated-milkshakes) [July 12, 2023 ###### 2011 Listeria outbreaks linked to cantaloupes: A history A total of 148 persons infected with any of the five outbreak-associated strains of Listeria monocytogenes were reported to the CDC from 28 states. The number of infected persons identified ... ](https://marlerclark.com/news_events/2011-listeria-outbreak-linked-to-cantaloupes-a-history) [March 26, 2023 ###### Listeria linked to yogurt prompts recall Clio Snacks of Piscataway, New Jersey, is voluntarily recalling 581 cases of its Strawberry Granola & Greek Yogurt Parfait Bar due to potential contamination with Listeria monocytogenes, an organism which ... ](https://marlerclark.com/news_events/listeria-linked-to-yogurt-prompts-recall) [November 20, 2022 ###### Enoki Mushrooms recalled again As of November 15, 2022, two people infected with the outbreak strain of Listeria have been reported from two states. Sick people’s samples were collected from October 5, 2022, to October 8, 2022. ... ](https://marlerclark.com/news_events/enoki-mushrooms-recalled-again) [1. View all ](/news_events/outbreaks?illness=listeria&year=all) ## All Listeria Resources [###### Listeria Food Poisoning ](https://marlerclark.com/foodborne-illnesses/listeria/about-listeria) [###### The Incidence of Listeria Infections ](https://marlerclark.com/foodborne-illnesses/listeria/the-incidence-of-listeria-infections) [###### The Prevalence of Listeria in Food and the Environment ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-prevalence) [###### Transmission of and Infection with Listeria ](https://marlerclark.com/foodborne-illnesses/listeria/transmission-of-and-infection-with-listeria) [###### 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) [###### What Are the Symptoms of Listeria Infection? ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-symptoms-risks) [###### Complications of Listeria Infection ](https://marlerclark.com/foodborne-illnesses/listeria/complications-of-listeria-infection) [###### How is Listeria Infection Diagnosed? ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-diagnosis) [###### Treatment for Listeria Infection ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-treatment) [###### Antimicrobial Resistance in Bacteria ](https://marlerclark.com/foodborne-illnesses/listeria/antimicrobial-resistance-in-bacteria) [###### The Economic Impact of Listeria Infections ](https://marlerclark.com/foodborne-illnesses/listeria/the-economic-impact-of-listeria-infections) [###### Preventing Listeria Infection ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-prevention) [###### Listeria References ](https://marlerclark.com/foodborne-illnesses/listeria/listeria-references) ### Other foodborne illnesses [E. coli](https://marlerclark.com/foodborne-illnesses/e-coli) [Salmonella](https://marlerclark.com/foodborne-illnesses/salmonella) [Hepatitis A](https://marlerclark.com/foodborne-illnesses/hepatitis-a) [Reactive Arthritis](https://marlerclark.com/foodborne-illnesses/reactive-arthritis) [Guillain-Barre Syndrome](https://marlerclark.com/foodborne-illnesses/guillain-barre-syndrome) [Irritable Bowel Syndrome](https://marlerclark.com/foodborne-illnesses/irritable-bowel-syndrome) [Norovirus](https://marlerclark.com/foodborne-illnesses/norovirus) [Botulism](https://marlerclark.com/foodborne-illnesses/botulism) [Campylobacter](https://marlerclark.com/foodborne-illnesses/campylobacter) [Shigella](https://marlerclark.com/foodborne-illnesses/shigella) [Cyclospora](https://marlerclark.com/foodborne-illnesses/cyclospora) [Hemolytic Uremic Syndrome](https://marlerclark.com/foodborne-illnesses/hemolytic-uremic-syndrome)