Investigation ongoing for listeria source

State health investigators are still attempting to solve several cases of food-borne infections that have caused several pregnant women to lose their babies since January.

They suspect the women in Yakima, Klickitat and King counties ate unpasteurized cheese that was contaminated with listeria bacteria.

“We’re trying to stop this tragedy from happening again but haven’t been able to find the source of the problem,” said Donn Moyer, spokesman for the Washington state Department of Health.

Listeria is often found in soft cheeses such as Mexican-style queso fresco and queso Blanco, along with feta, brie, camembert, Roquefort and bleu.

Pregnant women and their newborns are 20 times more likely than other healthy adults to be infected. People with suppressed immune systems are also at risk of becoming seriously ill from listeria, which can result in bloodstream infections or meningitis. They should avoid foods such as raw milk and deli foods such as sandwich meats, salads and vegetables.

The Yakima Public Health Department reported last week that early laboratory results indicated that the listeria infections came from a common source.

Two of the women had miscarriages. Another baby was stillborn. Another newborn baby infected was treated with antibiotics, Moyer said.

Symptoms can include diarrhea, fever, headache and muscle aches.