UC Riverside scientists confirm, for the first time, that a potentially fatal dog parasite is present in a portion of the Colorado River that runs through California. 

The parasite, Heterobilharzia americana, is a flatworm commonly referred to as liver fluke. Previously found almost exclusively in Texas and other Gulf Coast states, it has never been reported this far west. The worm can cause canine schistosomiasis, an illness that impacts the liver and intestines of dogs. 

“Dogs can die from this infection, so we are hoping to raise public awareness that it’s there,” said UCR nematology professor Adler Dillman. “If you’re swimming in the Colorado River with them, your pets are in peril.”

After learning about cases of the infection in local dogs, Dillman assembled a research team and headed to Blythe, a border town east of Joshua Tree National Park in Riverside County, where the sick dogs had all spent time swimming in the river.