According to press reports, the Tacoma-Pierce County Health Department is investigating a cluster of listeriosis cases that occurred between February 27th and June 30th 2023. Five diagnosed cases have been identified, all requiring hospitalization and resulting in three fatalities.
Listeriosis is associated with consumption of contaminated dairy products and cold cuts although no vehicle of infection has been identified in this cluster. The patients were infected with the same strain of Listeria applying whole genome sequencing, suggesting a common source.
The actual number of cases is probably far greater than is indicated by the diagnosed individuals since the elderly and pregnant are more susceptible to severe clinical consequences of infection.