The parasite that causes rat lungworm disease, long associated with Hawaii, was detected in California at the San Diego Zoo, raising concerns that the debilitating illness could become more widespread.

Hawaii is the hot spot for rat lungworm disease in the U.S., with more than 80 cases that were laboratory-confirmed from 2016 to 2026. Still, it’s considered a highly underdiagnosed disease. The largest number of rat lungworm cases occur on the island of Hawaii.

People have contracted the disease after finding a slug in washed salad, eating unwashed fruit or vegetables and even eating a slug on a dare. Awareness of the disease has altered the way some Hawaii residents buy produce, where they choose to purchase salads or smoothies from, and how they prepare fruits and vegetables at home before eating them.

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While no human cases have originated in California so far, Hawaii’s experience with the illness is a preview of what California residents and doctors should know about the disease and how to avoid it.

‘It’s probably all over the place’

Hawaii researcher Susan Jarvi, who has studied rat lungworm in the Aloha State for more than a decade and retired last year, told SFGATE that she isn’t surprised it has been found in Southern California. The parasite is likely more widespread than people know, since it’s not routinely tested for, she said. 

Don't let Google decide who you trust.

“It’s probably more prevalent, probably across the country, especially in the southern portions. It’s probably all over the place. We know it’s in Louisiana, Texas, Georgia,........

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