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Sick moose calf suffered from brainworm

A moose calf befriended by passing motorists in Fredenberg Township in late March was suffering from brainworm infestation, said Mike Schrage, a wildlife biologist with the Fond du Lac Band of Lake Superior Chippewa.

A moose calf befriended by passing motorists in Fredenberg Township in late March was suffering from brainworm infestation, said Mike Schrage, a wildlife biologist with the Fond du Lac Band of Lake Superior Chippewa.

A veterinary pathologist with the University of Minnesota's Veterinary Diagnostic Lab told Schrage Monday that the moose calf had been infected by brainworm, a parasite that destroys a moose's brain and can cause death.

Schrage and conservation officers from the Fond du Lac band observed the calf on March 24 and eventually decided to shoot it and submit it to the laboratory for examination.

"There were a lot of holes in the brain tissue," Schrage said after talking with a pathologist at the veterinary lab. "That indicated serious larval migration, that the worms were crawling around in the brain. The usual suspect is Parelaphostrongylus tenuis, the brainworm."

Anibal Armien, a veterinary pathologist at the University of Minnesota's Veterinary Diagnostic Lab, confirmed that information and the brainworm diagnosis on Tuesday.

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"The moose also had a number of liver flukes," Schrage said. "It's hard to know if that would have killed the moose, but it certainly didn't help the animal's condition."

The moose calf had been observed by motorists along the Taft Road for nearly a week before it was killed. Schrage examined the moose closely before determining that it was likely suffering from disease. The 10-month-old calf weighed 284 pounds, which was less than it should have weighed, he said.

Schrage and the Fond du Lac band are cooperating with the Minnesota Department of Natural Resources and other agencies in an ongoing moose research project in Northeastern Minnesota. Schrage said this calf's behavior was similar to other sick animals that researchers have seen.

The calf was one of five "sick-acting" moose calves reported this spring, Schrage said. Two others have been sent to the Veterinary Diagnostic Lab, but results of those examinations are not available yet, he said.

There is no treatment for wild animals suffering from brainworm, Schrage said.

Many who saw this calf said its mother was not around. That isn't uncommon for calves suffering from disease, Schrage said.

"Every time I've had a report of a sick moose calf, I've never found the mother," he said.

He suspects the cow moose know they're "dealing with a lost cause" and abandon the calves.

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Others who observed the Taft Road moose calf said it was still eating. Some people, in fact, fed the moose branches from trees. A sick moose eating is common, Schrage said.

"I've never done a field necropsy on a moose carcass and found anything other than a full stomach. They always have something in the stomach," he said. "They've been eating but seem to get no value from it. They're often very skinny."

The Northeastern Minnesota moose population is declining slowly, according to the ongoing research project. Mortality rates in the population are higher than those for most other North American moose populations. Causes of the increased mortality are not clear, biologists say. A warming climate and parasites such as brainworm and liver flukes are all suspected of playing a part in the population decline.

Related Topics: HUNTING
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