Scientists say dog-killing parasite found in new state
A dog-killing parasite that was believed to only exist in Texas and other Gulf Coast states has been discovered as far west as California for the first time, scientists have warned.
Experts at the University of California Riverside found the Heterobilharzia americana parasite, a flatworm commonly known as a liver fluke, in spots along the Colorado River where it runs through Southern California. According to the university, the flatworm has never before been seen outside of Texas and surrounding areas, and other studies have found most infections occur in Texas and Louisiana, though some have occurred in North Carolina and Kansas.
The worm can cause canine schistosomiasis, an illness that impacts the liver and intestines of dogs. While there are treatment options, they are not always successful.
“Dogs can die from this infection, so we are hoping to raise public awareness that it’s there,” said UCR nematology professor Adler Dillman in a statement. “If you’re swimming in the Colorado River with them, your pets are in peril.”
Scientists took to examining the waters in Riverside County, Calif. after several cases of infection were reported in local dogs. Because the infection is generally transmitted via the presence of snails, the research team collected more than 2,000 along the banks of the Colorado River and examined DNA to identify the presence of the snails and the flatworm.
The team was surprised to find two species of snail that can carry the parasite. “Not only was it a surprise to find H. americana, we also did not know that the snails were present here,” Dillman said in a statement.
The parasite first makes its way into the snail’s body and matures while traveling through its system. It then must find a mammal host within 24 hours before it is unable to survive further on its own. Dogs and raccoons are specifically susceptible to acquiring one of these worms via fresh water, whether by swimming in it or drinking it.
A worm can enter into the veins of the intestinal lining, where it will mature, mate and lay eggs. The eggs then get into the lungs, spleen, liver, and heart, causing an autoimmune reaction, according to Dillman. The immune system responds by forming clusters of cells called granulomas, which eventually lead to organ tissue failure.
The parasite is not capable of causing such infection in humans.
It may take several months before notable and serious symptoms appear following infection.
Symptoms tend to occur gradually, according to Emily Beeler, a veterinarian with the Los Angeles County Department of Public Health. Loss of appetite, vomiting, diarrhea, profound weight loss, and signs of liver disease are all symptoms associated with the progression of the disease.
“If your dog has these symptoms after swimming in the Colorado River, it’s a good precaution to ask your veterinarian for a simple fecal test,” said Beeler. “Treatment typically involves use of multiple medications and close monitoring of the dog by a veterinarian.”