Silver Bay Moose had brain parasite

• A Sick Moose

A moose bedded down just west of Silver Bay in October was eventually shot and killed by a Minnesota DNR conservation officer because it was causing a traffic hazard and it was feared to have a brain disease. An autopsy has shown the young bull moose had brainworm. Submitted photo

Talk about it

A moose that met a rather public death along a Lake County road in early October had a brainworm infection, moose expert Mike Schrage reported this week. The disease is one of many being found in a dwindling moose population in the state.

The young bull moose created quite a stir the week before the moose hunting opener as it bedded down at the intersection of county roads 4 and 5 just west of Silver Bay. Schrage, a wildlife biologist for the Fond du Lac Band in Cloquet, was called up to check the moose out along with county deputies and Minnesota DNR officers.

“It had been there a long time,” Schrage said of the unusual behavior. People had pulled over on the roads to take pictures of the moose just 20 yards from the pavement, he said. “A wild moose should not just be sitting there,” Schrage said. “This isn’t Yellowstone park.”

He was causing a traffic hazard and likely had some sort of disease, he and the officers surmised. They attempted to get closer to the animal but at 10 yards away he moved into some woods further back from the road. Schrage said there was nothing obviously wrong with him physically but the behavior was off. The moose returned to the roadside 10 minutes later and the decision was made to take it down.

The brain, blood and fecal matter were studied and it turned out the moose had a brainworm, a parasite that affects the activity of moose, causing the kind of sedentary behavior seen in October.

It was a clear case, said Dr. Erika Butler, a wildlife veterinarian for the DNR. A cross section of the brain shown under a microscope clearly shows the worm. “You often don’t find the actual worm,” Schrage said.

Brainworm isn’t necessarily deadly by itself, experts say. Schrage said other factors along with the parasite can be attributed to the loss of moose in the Minnesota range. “There’s a debate on the importance (of brainworms),” he said.

Worm larvae go into the bloodstream of animals and eventual are passed through feces. Foraging animals ingest the snails or slugs on forest floors. Moose can gain symptoms in as little as 60 days.

It’s a common parasite in whitetail deer, Schrage said, but it doesn’t react in their bodies as it does in moose. In moose, the symptoms of lethargy, blindness, inability to stand, and rapid eye movements make the animal more susceptible to predators like wolves.

The parasite wasn’t diagnosed until the 1960s, Schrage said, but the symptoms have been reported as far back as 1912. With the moose population under more scrutiny than ever before, there have been a number brainworms found recently, Schrage said. Some have survived and done well.

“There are a number of other potential health issues we’re concerned about for our moose herd,” he said.

Knife River update

Regional wildlife biologist Mike Schrage said the moose spotted near Knife River at the end of the year is still in the area, but north of Highway 61 and the busy expressway. The collared moose was in the area right before Christmas and another aerial check is being done this week.

Moose do not move much once situated, Schrage said. This moose moved from the Finland and Isabella areas where many of the 150 moose tracked by state wildlife experts are found. They tend to stay in the same 20-mile area, Schrage said.

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