WebMD Newsroom

by Daniel J. DeNoon

Three more people have died and 10 more have fallen seriously ill as the listeria outbreak from tainted cantaloupe grinds on.

The outbreak, traced to listeria bacteria growing on packing equipment at Colorado’s Jensen Farms, now has sickened 133 people in 26 states. So far, 28 deaths are reported.

In terms of case numbers, the current outbreak is nine cases short of becoming the largest listeria outbreak in U.S. history.

The biggest previous outbreak was in 1985 in Los Angeles County. It was caused by Mexican-style cheese made from raw milk. Nearly two-thirds of the 142 cases were in pregnant women. There were 28 deaths — 18 in non-pregnant adults and 10 in newborns — and 20 miscarriages or stillbirths.

Even though the source of the current outbreak has been found and the contaminated cantaloupes recalled (or, by now, spoiled), the toll continues to rise. That’s due to two things: delays in reporting cases, and the fact that listeria can take up to two months to cause serious symptoms.

Listeria isn’t the only food poisoning danger. But it’s one of the most deadly. While it rarely causes more than mild diarrhea in young, healthy people, listeria can cause deadly encephalitis or meningitis in older people, or in those with suppressed immune systems.

Pregnant women, too, are particularly susceptible. While they rarely get seriously ill themselves, the bacteria tend to accumulate in the placenta, often causing miscarriage or stillbirth. And infected women can pass the bug on to newborns during birth, with often devastating consequences.

There have been four pregnancy-related cases in the current outbreak. One was in a newborn; the outcome is not yet known. One of the three cases in pregnant women led to a miscarriage.

It’s hard to tell when this outbreak will be over. It’s already the second largest listeria outbreak in U.S. history — and case reports are still coming in.