Cat Disease Contaminates Waterways, Spreads to Minks in Illinois

Disease is spreading in Illinois, but not in a way you'd suspect. Toxoplasmosis, a bizarre brain disease caused by parasite infection, is apparently rapidly spreading among minks and muskrats in the state, and kitty litter may be to blame.

Toxoplasma gondii, the parasite that causes toxoplasmosis, exclusively reproduces in cats, and the goal of new oocysts created is to find their way to a new feline host. In order to do this, they first need to leave their "home" cat and somehow survive outside a body until they find their way to a new host.

Feces is the main way in which they accomplish this, where excrement can spread the parasites to soil, where they can then find their way into a rodent.

Researchers have long known that toxoplasmosis in rodents usually leads to unhealthy behavioral changes, including a loss of caution around the odor of cats, making them easier prey. In this way, the parasite finds its way to another cat through predation.

However, this doesn't always work as intended. Past research has revealed that kitty litter carrying T. gondii often finds its way to landfills or backyards,from which groundwater carries the parasites to local waterways. Eventually these parasite infect animals that will never find thier way into a cat's belly, including sea otters.

A new study, recently published in the Journal of Wildlife Diseases, details how this waterway contamination may be the same way that toxoplasmosis is becoming so worryingly prevalent in Illinois, where heavy rainfall is causing watershed areas to become flooded with parasite eggs.

Research lead Adam Ashlers, from the University of Illinois, explained in a statement that while he and his colleagues had expected T. gondii to have spread to some muskrat and mink populations, they were surprised at how common infections were. Sixty percent of muskrats tested in field surveys had been exposed to the parasite. A stunning 77 percent of all minks tested were also infected.

"Minks have larger home ranges. They leave the stream system and they're eating mice and birds and other animals that could have the disease," Ahlers said. "Muskrats are always in the stream channel and are picking up the disease passively - probably through grooming or drinking water. They're herbivores, so it's also likely they're picking it up by consuming oocysts attached to aquatic vegetation."

The researchers found confirmation of their water contamination theory after it was revealed that Muskrats in larger watersheds had higher infection rates than those from smaller watersheds. However, more large-scale evidence will be needed to make it a certainty.

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