Researchers Reveal Dog-Killing Parasite Present Near Mead Lake In US

Signs of a dangerous freshwater parasite have been found around Lake Mead and Lake Mohave, but researchers say the risk to dogs looks low for now. A two-year survey by the National Park Service found evidence that the parasite is present in wildlife, even though it was not found in the snails that usually spread it, reported Newsweek.

This parasite, Heterobilharzia americana, can cause a dangerous disease in dogs called canine schistosomiasis. It was recently spotted along the Colorado River, with several dogs falling ill near Blythe. This suggests that the parasite has now spread beyond its usual habitat on the Gulf Coast and other southern states.

What The Research Revealed

According to a report in the Nevada Current, researchers found eggs of the parasite in raccoon feces samples near the lakes. This suggests that the parasite is spreading among local wildlife, although it was not directly detected in snails in the areas examined.

According to the report, after reports of about a dozen dogs falling ill after visiting the river near Blythe in 2024, NPS aquatic ecologist Riley Rackliffe led a survey of 28 locations on both lakes. The team collected and examined approximately 1,300 freshwater snails, as well as raccoon fecal samples. They collaborated with the University of California, Riverside, which first identified the outbreak near Blythe.

During the survey, no snails were found infected, but parasite eggs were found in raccoon feces. According to Rackliffe, these eggs were found in several locations, including Lake Mead and most of the marina area. This clearly indicates that the parasite is present and has infected raccoons.

Rackliffe explained that the host plants needed by the snails, such as cattails, are very limited in these lakes. Because such snails are so rare, the likelihood of dogs becoming infected in these two lakes appears low.

According to the Nevada Current, no cases of the disease have yet been reported in dogs in the Las Vegas-Lake Mead area. Rackliffe also said that some cases may have gone undetected because local veterinarians didn't typically screen for it in the past.

What Is Heterobilharzia Americana

Heterobilharzia americana is a parasite found mostly in the Gulf Coast region of the United States. According to the Companion Animal Parasite Council, dogs can become infected when they swim or walk in contaminated freshwater and the parasite's larvae enter their bodies through their skin.

How Can It Affect Humans?

In humans, this parasite can cause a condition called "swimmer's itch." According to the Centers for Disease Control and Prevention, symptoms include redness and itching of the skin while in or after getting out of water.