Rat lungworm found in San Diego opossums, rats and zoo animal

Rat lungworm, a parasite that can infect certain animals and humans and prove fatal, was found in wild opossums, rats and a wallaby at the San Diego Zoo, according to a new study published by the U.S. Centers for Disease Control and Prevention.

Not previously believed to be established in California, the rat lungworm cases were identified in multiple animals primarily last year, and as early as 2023, according to the study published this month in the CDC’s scientific journal, Emerging Infectious Diseases.

The researchers said that while the risk of transmission to humans is low, it can lead to neurological illness, meningitis or even death. They characterized the parasite as “an emerging veterinary and public health concern.”

The parasite’s usual life cycle involves infected rodents passing the larvae through their feces, which is then eaten by gastropods, such as snails and slugs, according to the study. Other rodents then eat the gastropods and become infected with the disease. Frogs, lizards and crustaceans have also been known to transfer lungworm when ingested by animals. And a University of Sydney study reported that both humans and dogs could be susceptible to the parasite.

Originating in southern China in 1935, the parasite has spread across the world over the last century, including in Ha...