Scientists have issued a warning after discovering a dog-killing parasite, previously thought to be limited to Texas and other Gulf Coast states, now appearing as far west as California.
Researchers at the University of California Riverside identified the Heterobilharzia americana parasite, commonly known as a liver fluke, along the Colorado River in Southern California. This flatworm, previously unseen outside of Texas and its neighboring regions, primarily affects dogs, causing canine schistosomiasis, a disease impacting the liver and intestines.
Nematology professor Adler Dillman, from UCR, emphasized the severity of the infection, stating, “Dogs can die from this infection, so we are hoping to raise public awareness that it’s there. If you’re swimming in the Colorado River with them, your pets are in peril.”
The discovery came following reports of infections in local dogs in Riverside County. Researchers collected over 2,000 snails along the riverbanks to trace the presence of the parasite, as it is primarily transmitted through snails.
Unexpectedly, the research team found two species of snail capable of carrying the parasite, highlighting the broader ecological implications. Dillman expressed surprise, stating, “Not only was it a surprise to find H. americana, we also did not know that the snails were present here.”
The parasite enters the snail’s body, eventually making its way to mammals, particularly dogs and raccoons, through freshwater sources. Once inside a mammal, the worm matures, mates, and lays eggs, leading to severe health issues. Symptoms include loss of appetite, vomiting, diarrhea, weight loss, and signs of liver disease.
Dr. Emily Beeler from the Los Angeles County Department of Public Health emphasized the importance of seeking veterinary attention for dogs exhibiting these symptoms after swimming in potentially contaminated waters. Treatment typically involves multiple medications and close monitoring by a veterinarian.
While the parasite does not infect humans, it has impacted several dogs in California, with one reported fatality since 2019. With this concerning discovery, experts urge dog owners to be cautious when allowing their pets to swim in freshwater sources, as many can sustain these parasites, even if not previously identified in those waters.
