Deadly Dog Parasite Found in the California Section of the Colorado River

Friday - March 22 2024, 20:21 UTC - 8 months ago

A deadly dog parasite, Heterobilharzia americana, has been found for the first time in the California section of the Colorado River. This parasite, transmitted by snails, can cause canine schistosomiasis and has been linked to the death of one dog. Health officials are urging pet owners to be cautious and aware before letting their dogs swim in the river. While the parasite is not harmful to humans, its presence in a popular recreational area is concerning.

A team of scientists at UC Riverside have made a disturbing discovery - the liver fluke parasite, also known as Heterobilharzia americana, has been found in the western section of the Colorado River in California. This is the first time that this potentially deadly parasite has been confirmed in this area.

The parasite, which is commonly found in Texas and other Gulf Coast states, is a flatworm that can cause canine schistosomiasis - a serious illness that affects the liver and intestines of dogs. This can lead to death if left untreated.

UCR nematology professor Adler Dillman expressed concern, 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 research team, led by Dillman, began investigating after learning about cases of the infection in local dogs. They headed to Blythe, a border town east of Joshua Tree National Park in Riverside County, where all the sick dogs had recently spent time swimming in the river.

Their findings were alarming. They discovered that the parasite is transmitted by a specific type of snail that is present on the banks of the river. The team collected over 2,000 snails and used DNA to confirm the identity of both the snails and the flatworm. The results were published in the journal Pathogens this week.

Dillman revealed, "We actually found two species of snails that can support H. americana in the river in Blythe, and we found both snails actively shedding this worm. Not only was it a surprise to find H. americana, we also did not know that the snails were present here." .

Once inside the snail, the worm transforms and then looks for a mammal to infect. It can only survive on its own for about 24 hours during this stage. If a dog or a raccoon is in the water, or drinks the water, they can become infected.

Dillman explains, "It gets into the veins of the intestinal lining, and that's where it develops into an adult and mates. The presence of the adults in the veins isn't the problem. It's the eggs that get into the lungs, spleen, liver, and heart. The immune system tries to deal with it, and hard clusters of immune cells called granulomas form. Eventually, the organ tissues stop functioning." .

Symptoms of canine schistosomiasis can take several months to appear, but it is important to seek treatment as soon as possible. Since 2019, 11 dogs in three counties of California have been confirmed with the infection, and sadly, one has died. Health officials are urging pet owners to be aware and take precautions to prevent further infections and deaths.

Dr. Emily Beeler, a veterinarian with the Los Angeles County Department of Public Health, advises, "Symptoms start gradually with a loss of appetite, and eventually include vomiting, diarrhea, profound weight loss, and signs of liver 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. Treatment typically involves the use of multiple medications and close monitoring of the dog by a veterinarian." .

It is important to note that while H. americana is not known to be harmful to humans, the mere presence of the parasite in a popular and beloved recreational area is concerning. It is reassuring, however, that the infection is not transmissible from dogs to humans.

This discovery serves as a reminder to all dog owners to be vigilant and take precautions before letting their pets swim in the Colorado River. The health and safety of our furry friends should always be a top priority.