A Brain-Invading Parasite Just Showed Up in California
Something called rat lungworm has been found in wild animals in San Diego County and yeah, it's exactly as bad as it sounds.
This parasite can get into your brain and spinal cord and cause meningitis, neurological damage, and in serious cases, death. Researchers just confirmed its presence in California for the first time after finding it in zoo animals, wild rats, and opossums across San Diego County. Doctors in the area are now being told to consider it when patients walk in with unexplained neurological symptoms.
The risk to most people is low. But it's still worth knowing about.
How People Actually Get It
Slugs and snails eat rat feces that contain the worms' larvae. When a person accidentally eats an infected slug or snail — or eats produce a slug crawled across without washing it — those larvae end up in the wrong host. From there they migrate toward the brain and spinal cord, and things go downhill from there.
Severe headaches, stiff neck, tingling skin, nausea, fever. In bad cases, coma or death. Symptoms can hit within hours of exposure and drag on for weeks. Eventually the worms will die, but what happens in between is what needs to be taken seriously.
Freshwater crabs, prawns, frogs, and snails are the highest-risk food to carry them. Unwashed produce is the sneakier risk most people don't think about. The larvae need moisture to survive though, so thoroughly dry produce is generally safe.
What They Found in San Diego
Late last year a 7-year-old wallaby at the San Diego Zoo started showing neurological symptoms out of nowhere. Head shaking, blindness, paralysis. He was euthanized after 11 days and when staff examined his brain, they found six rat lungworms and serious damage throughout.
Zoo staff then tested 64 roof rats found dead or caught on the property. Two tested positive, and their feces were packed with live larvae — around 300 per sample, each about the size of a grain of sand.
Across town, a wildlife rehab center called Project Wildlife had been receiving sick opossums from around the county. Of 10 dead animals tested, seven carried the worms.
Rats, opossums, a zoo wallaby — different species, different parts of the county. That's what made researchers confident enough to call this an establishment rather than a fluke.
What To Do
Wash your produce. That's really the big one for most people. Slug slime on unwashed greens can carry larvae, and it doesn't take much. Rinse all produce before you eat it.
No human cases have been reported in California so far, and health officials say the parasite hasn't been detected outside San Diego County yet. More testing is underway to figure out how far this has actually spread.
If you have pets that spend time outside in the area, keep an eye on them. Dogs and cats are vulnerable too.
And if you've potentially been exposed and symptoms start showing up, get to a doctor fast and mention the possibility. Hawaii has dealt with this parasite for years and the lesson they keep pushing is simple — don't wait. Early treatment with corticosteroids and antiparasitic medication works. Waiting doesn't.
Wash your produce. Don't eat wild snails or raw or undercooked seafood. You'll probably be fine.
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