The CDC confirmed rat lungworm infection, which can cause meningitis in humans, in 12 people between 2011 and 2017 — raising questions about how common the parasitic infection is.
Researchers may not have learned about all the rat lungworm illnesses in the continental U.S. during those six years, a CDC report stated.
U.S. healthcare providers, particularly those in the South, must consider the infection in patients with eosinophilic meningitis, particularly those who may have ingested snails or raw vegetables contaminated with larvae, the CDC said.
The cases studied were in Alabama, Arizona, California, Colorado, New York, Tennessee, Texas and Utah. The patients may have inadvertently ingested the parasite with their garden produce if it was not washed well, a CDC official said.
"Some of the fresh produce had been grown in the backyard," Sue Montgomery, a senior epidemiologist at the CDC's parasitic diseases branch, told NBC News. "They probably inadvertently ate a snail or slug."
At least six of the patients said they consumed raw vegetables, two had eaten raw snails, two had eaten prawns and one ate cooked crab. For two others, "family members reported the presence of snails in the environment," the CDC report said.
Rat lungworm can spread to the brain and cause meningitis, neurologic deficits, coma and death.