The US Centers for Disease Control and Prevention (CDC) and its state health partners are investigating a Listeria outbreak linked to deli-sliced meat and cheeses that has sickened eight people, one of them fatally, in four states.

In an announcement yesterday, the CDC said the people first became sick between Nov 14, 2016, and Mar 4, 2019, and that whole-genome sequencing of Listeria monocytogenes samples from sick patients shows a close match, meaning the people likely shared a common source. Also, Listeria samples from deli counters in multiple retail locations closely match the strain from sick people.

Cases in Pennsylvania, Michigan, New York, New Jersey

The four states reporting cases are Pennsylvania (3) Michigan (2), New York (2), and New Jersey. All patients were hospitalized, and the patient who died is from Michigan. Patients range in age from 40 to 88, and five are men and three are women.

Listeria can survive at very low temperatures and can spread easily to other foods and surfaces, the CDC said. Pregnant women and their newborns, elderly people, and those with weakened immune systems are at highest risk. Symptoms include headache, stiff neck, confusion, balance problems, and convulsions, as well as fever and muscle aches.

Patients with invasive listeriosis usually report symptoms 1 to 4 weeks after eating contaminated food, but symptom onset can range anywhere from the day of exposure to 70 days after.

In the epidemiologic part of the investigation, interviews with six of the patients about the foods they ate and other exposures they had before they got sick found that five reported products sliced at deli counters, including meats and cheese. However, delis where they shopped served many different brands of products, with limited details about brands they bought.

No specific product identified

Officials from the US Department of Agriculture's Food Safety and Inspection Service and the Food and Drug Administration have combed through records that state inspectors collected from delis where sick people ate, but so far, a common product has not been found.

Meanwhile, in the lab part of the investigation, the Listeria outbreak strain was found in samples from meat sliced at a deli and from deli counters in multiple retail locations in New York and Rhode Island.

The CDC at this point isn't advising consumers to avoid eating food prepared at delis or that retailers stop selling deli-sliced products.

Officials warned, however, that people at higher risk of infection for severe listeriosis to handle deli-sliced meats and cheeses carefully and that retailers clean and sanitize deli slicers and other areas where deli products are prepared, stored, or served to avoid cross-contamination.

See also:

Apr 17 CDC outbreak announcement