Key Facts:

  • 11 with Illnesses – 10 hospitalized – 10 states.
  • Illnesses began July 3, 2018 with last reported January 31, 2023.
  • State’s impacted – Arkansas, California, Colorado, Michigan, Missouri, New York, North Carolina, Pennsylvania, South Dakota and Washington.
  • No food product has been identified.

CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of Listeria monocytogenes infections. A specific food item has not yet been identified as the source of this outbreak. CDC advises people who are pregnant, aged 65 or older, or have a weakened immune system to contact their healthcare provider if they have any Listeria symptoms.

As of February 14, 2023, a total of 11 people infected with the outbreak strain of Listeria have been reported from 10 states – Arkansas, California, Colorado, Michigan, Missouri, New York, North Carolina, Pennsylvania, South Dakota and Washington. 

Sick people’s samples were collected from July 3, 2018, to January 31, 2023.

The true number of sick people in this outbreak is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Listeria. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.

Public health officials collect many different types of information from sick people, including their age, sex, other demographics, and the foods they ate in the month before they got sick. This information provides clues to help investigators identify the source of the outbreak.

Sick people range in age from 47 to 88 years, with a median age of 73, and 73% are female. Race or ethnicity information is available for ten sick people. One sick person reported Hispanic ethnicity. Of nine people that did not report Hispanic ethnicity, eight are White and one is African American/Black. Of ten people with information available, all have been hospitalized. No deaths have been reported. State and local public health officials are interviewing people to find out what foods they ate in the month before they got sick.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.

What is Listeria?

Listeria is a bacterium that causes a serious infection called listeriosis. Around 300 deaths are caused by Listeria infection each year, according to estimates from a 2011 CDC report. 

Listeria bacteria are most commonly found in raw foods. Vegetables can be contaminated by soil and water carrying bacteria. Listeria is also found in raw animal products, such as meat and cheese. 

Babies can be born with Listeria if the mother eats contaminated food during pregnancy. The death rate among newborns with Listeria is 25 to 50 percent. 

Who is most likely to get seriously ill from Listeria bacteria?

Healthy adults and children hardly ever become seriously ill from Listeria. However, people at increased risk of illness from Listeria bacteria include:

  • Pregnant women – Pregnant women are 20 times more likely to get listeriosis than the average healthy adult
  • Newborns
  • People with weak immune systems
  • People with cancer, diabetes, or kidney disease
  • People with AIDS – People with AIDS are 300 times more likely to get sick from Listeria than people with normal immune systems
  • People who take gluticocorticosteroids such as cortisone
  • Elderly people

Symptoms of Listeria

Listeria symptoms appear anywhere between 3 and 70 days after infection, but usually around 21 days later. Typical symptoms include:

  • Fever
  • Muscle aches
  • Nausea or diarrhea (less common)

If infection spreads to the central nervous system, symptoms can include:

  • Headache
  • Stiff neck
  • Confusion
  • Loss of balance
  • Convulsions

If a patient has a weak immune system, Listeria bacteria can invade the central nervous system and cause meningitis or a brain infection. 

Infected pregnant woman experience mild, flu-like symptoms. However, infection during pregnancy can lead to miscarriage, infection of the newborn, or stillbirth. Symptoms usually appear in newborns in the first week of life but can also occur later on. A newborn’s Listeria symptoms are often subtle, and include irritability, fever, and poor feeding.

Diagnosis of Listeria

Doctors can determine whether patients have listeriosis by taking a blood or spinal fluid sample.

Treatment of Listeria

Patients who present with symptoms of listeriosis can be treated with antibiotics. If a pregnant woman takes antibiotics promptly after contracting Listeria, she can usually prevent the spread of the Listeria bacteria to her child. Babies who have listeriosis usually take the same antibiotics as adults. 

How to Prevent Listeria

  • Thoroughly cook raw food from animal sources, such as beef, pork, or poultry
  • Wash raw vegetables before eating them
  • Keep uncooked meats separate from vegetables and cooked foods 
  • Avoid products made with unpasteurized milk
  • Wash hands and cooking utensils after handling uncooked foods
  • Consume perishable and read-to-eat foods as soon as possible
  • Do not eat hot dogs or lunch meats unless they are heated to a temperature sufficient to kill Listeria bacteria
  • Avoid getting liquid from hot dog packages on other food
  • Wash hands after handling hot dogs and lunch and deli meats
  • Do not eat soft cheeses (e.g. feta, Brie, Camembert, blue cheese, and queso blanco) unless the label clearly states that they are pasteurized
  • Do not eat refrigerated pâté or meat spread, only canned or shelf-stable ones
  • Do not eat refrigerated smoked seafood, sometimes labeled as “nova-style,” “lox,” “kippered,” or “jerky.” Canned or shelf-stable smoked seafood is ok

Additional Resources:

Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Listeriaoutbreaks. The Listeria lawyers of Marler Clark have represented thousands of victims of Listeria and other foodborne illness outbreaks and have recovered over $850 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Listeria lawyers have litigated Listeria cases stemming from outbreaks traced to a variety of foods, such as lettuce, polony, deli meat, cantaloupe, cheese, celery and milk.  

If you or a family member became ill with a Listeria infection after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Listeria attorneys for a free case evaluation.