“Genetic fingerprinting results (whole genome sequencing) indicate that these patients likely have the same source of infection. Patients became ill between February 27 and June 30, 2023.” (Tacoma News Tribune)

Tacoma-Pierce County Department of Health reports that it is working with Washington State Department of Health (DOH) and Thurston County Public Health and Social Services to investigate 5 cases of the foodborne illness listeriosis in Western Washington

Four of the cases are in Pierce County. One is in Thurston County. All 5 patients were hospitalized and 3 died. All the cases were in patients with weakened immune systems in their 60s or 70s.

Investigators are interviewing patients or their proxies to help identify any common exposures.

Listeriosis is an infection caused by the bacteria Listeria monocytogenes. We see about 10-25 cases in Washington each year. Those most at risk for listeriosis are people who have a weakened immune system or are pregnant, newborn, or elderly. Centers for Disease Control and Prevention (CDC) says it is rare for people outside of these groups to get sick with Listeria infection.

The most common way people get listeriosis is by eating food contaminated with Listeria. Symptoms usually develop between 3-70 days after exposure. About half of those infected see symptoms within 3 weeks.

To protect yourself from listeriosis:

  • Avoid unpasteurized or raw milk, or food made from unpasteurized milk.
  • Thoroughly cook raw meat like beef, pork, or poultry.
  • Wash raw vegetables well before eating.
  • Keep uncooked meats away from vegetables and from cooked or ready-to-eat foods.
  • Wash your hands, knives, and cutting boards after you handle uncooked foods.
  • Eat perishable and ready-to-eat foods as soon as possible.  

People most at risk of infection should avoid:

  • Unpasteurized soft cheeses like queso fresco and brie.
  • Unheated hot dogs, lunch meats or deli meats. 
  • Refrigerated pâtés or meat spreads. 
  • Refrigerated smoked seafood, unless it is in a cooked dish like a casserole. 
  • Leftover foods or ready-to-eat foods unless heated or reheated to steaming hot before eating.
  • Premade deli salads like potato, tuna or chicken salad, or coleslaw.
  • Getting fluid from hot dog packages on other foods, utensils, and food preparation surfaces.  

Learn more on CDC’s website.

If you think you have a foodborne illness or serious infection, contact your healthcare provider, especially if you are at risk of severe infection.

You can report suspected foodborne illnesses or concerns in Pierce County on our website and in Thurston County here

DOH is leading this investigation and will continue to update information on its webpage. You can direct media inquiries to doh-pio@doh.wa.gov.