Bald eagles face a new threat this year, but humans and toxins are not the culprits.

The University’s Raptor Center confirmed that the West Nile virus killed four male bald eagles in the Minnesota and Wisconsin area last week, and the number could keep climbing.

Professor and Raptor Center Director Patrick Redig said he is “reasonably certain” another bald eagle in the center will test positive for the virus. The virus is transmitted from mosquitoes and can cause death in humans and animals.

“With the wet and warm weather, we might get another crop again,” he said.

The virus tends to infect birds, humans and horses, and it had been rare in bald eagles until this summer, Redig said.

More occurrences of the disease among bald eagles might stem from environmental changes, Redig said.

“Eagles are getting exposed in a way there weren’t before. That’s the bottom line,” he said.

Bald eagles are currently listed on the federal endangered species list. More than 3,000 bald eagles live in Minnesota and Wisconsin, Redig said.

“(West Nile virus) could have some bearing on the status of the eagle as a threatened species,” Redig said. “It represents another known cause of mortality.”

The human link

Two people have died from West Nile this year, the Minnesota Department of Health reported earlier this month. Four people died from the virus last year.

“The year’s not over yet, so we don’t know if we’ll have fewer deaths (than last year) because we expect to have additional cases come in,” Minnesota Department of Health communications specialist Doug Schultz said. “It’s still too early to say.”

He said the colder weather this summer might be why Minnesota had fewer cases this year.

The department constantly monitors behavior of the virus, he said.

Minnesota Department of Health epidemiologist Dave Neitzel said the department is studying species of mosquitoes that feed on birds and people.

“I think we have it pinned down to one species that is transmitting it to people,” he said.

Minnesota hosts 50 species of mosquitoes, he said.

Schultz said the biggest part in combating the virus is making people aware of it.

“You can control mosquitoes to some extent,” he said. “But it’s much more effective for people to protect themselves from mosquitoes than eliminate mosquitoes all together.”

Some University students said they are not worried about getting infected with the virus.

Sophomore Laura Nelson said the thought of coming into contact with the virus had crossed her mind, but it was not a major concern.

“I wasn’t outside a lot this summer, and when I was, I used mosquito spray,” she said.

Global studies senior Dan Emory also said he had thought about the potential of getting the virus, but it didn’t alter his outdoor behavior.

“The bugs haven’t been bad this year,” he said. “I’m not worried about it.”