Parasite discovered in Wisconsin trout stream for first time

The Wisconsin Department of Natural Resources (DNR) is urging anglers to thoroughly clean their equipment after discovering a specific parasite in a stream for the first time.

The DNR says the Myxobolus Cerebralis parasite has been found in Elton Creek in Langlade County – a Class 1 trout stream. The microscopic parasite has been found to damage the cartilage and nerve tissue of trout and salmon, oftentimes causing whirling disease, the DNR says.

"It’s unknown how Myxobolus Cerebralis will impact our local trout populations at this time," said Wisconsin DNR Fisheries Management Bureau Director Justine Hasz in a statement. "In some states where the parasite has been found, trout and salmon have developed whirling disease, which has negatively impacted local populations."

However, the DNR notes that not every state found to have the parasite has seen evidence of fish with whirling disease.

Myxobolus Cerebralis can only infect trout and salmon, with rainbow and brook trout thought to be the most susceptible. It cannot infect other fish species and poses no threat to humans or household pets.

According to the DNR, the parasite is nearly impossible to eradicate once it has been established, but steps can be taken to limit the spread – including cleaning and disinfecting equipment after fishing.

Signs of whirling disease include blackened tails, and skeletal deformities or swimming in circles. If any of these symptoms are spotted, anglers are encouraged to report sightings to their local fisheries biologist.

According to a press release, although no fish have been discovered to have clinical symptoms yet, the DNR is implementing a surveillance program to determine if trout populations have been affected. A list of other diseases that have been spotted among Wisconsin fish can be found here.