Listeria causes illness in fetuses, infants, at much lower dose than previously thought

Chapman is here in Manhattan (Kansas) for a couple days, delivering a seminar later today, hanging out at the Missouri-Kansas State football game tomorrow, and primarily helping plot our research and extension activities for the next few years.

We’ve both sired offspring in the past year-and-a-bit, so the issue of listeria and pregnant women has been a recurring theme – on, in research proposals, and in our microbiological nerd discussions.

Researchers from the University of Georgia reported in the journal, Risk Analysis, this month, that pregnant women may get ill from Listeria at lower doses than previously thought.

The risk of fetal or infant mortality among pregnant women who consume food containing 1 million cells of the food-borne pathogen Listeria monocytogenes in soft cheeses and other food is estimated at about 50 percent, suggesting five stillbirths potentially could occur when 10 pregnant women are exposed to that amount.

A previous risk assessment estimated more than 10 trillion cells would result in stillbirths to 50 percent of pregnant women exposed, researchers said.

"We’re not saying there’s a new epidemic here, we’re suggesting we’ve come up with a more accurate method of measuring the risk and how this deadly bacteria impacts humans, especially the most medically vulnerable among us," study co-author Mary Alice Smith of the University of Georgia said in a statement.

When estimates are extrapolated from data in tests on laboratory animals, the results showed "Listeriosis is likely occurring from exposure to lower doses than previously estimated," Smith said.

That’s a convoluted way of saying Listeria happens, and it’s probably more deadly than anyone thought for developing babies. Given the ridiculously low levels of awareness amongst physicians, health professionals and expectant mothers, new messages using a variety of media are needed so parents-to-be are at least aware of the risks of certain refrigerated, ready-to-eat foods.

The Centers for Disease Control and Prevention (CDC) has estimated approximately 2,500 cases of Listeriosis occur annually in the United States, with about 500 cases resulting in death. In 2000, Listeria exposure resulted in a higher rate of hospitalization than any other food-borne pathogen and more than one-third of reported deaths from food pathogens, the CDC says.