Minnesota's U.S. senators gathered infectious-disease experts at the University of Minnesota on Friday to discuss the Zika virus, amid research showing that a species of mosquito endemic to the Midwest could spread the virus in this state.

While causing little more than cold symptoms in most cases, a Zika infection in a pregnant woman can cause birth defects for her baby, and in others has been a rare cause of Guillain-Barré disorder, which severely weakens leg and arm muscles.

"The mosquito season is upon us in Minnesota," said U.S. Sen. Amy Klobuchar, D-Minn., "and we're starting to see this" virus in the United States.

Zika spread rapidly throughout South and Central America in recent months, but only emerged in the United States as winter travelers were bitten by infected mosquitoes.

Minnesotans have so far brought back 17 confirmed cases from tropical trips, a disproportionate 4 percent of the nation's 544 cases. North Dakota's first case involved a woman who gave birth after traveling to Puerto Rico; state health officials are monitoring the health of her baby.

One of the experts talking with the senators was Dr. William Stauffer, who works at the HealthPartners travel clinic, where 85 sickened travelers have been tested for Zika, three have been confirmed with infections, and one has Guillain-Barré.

The risk of Zika spreading in Minnesota remains low; while the virus can be spread through sex, research suggests it clears the body within two months — reducing chances for person-to-person transmission. But hopes that it only could be carried by tropical mosquitoes were dismissed last month when researchers found that the Aedes albopictus mosquito could bring the virus farther north than originally thought.

Michael Osterholm, who directs the U's Center for Infectious Disease Research and Policy, told Klobuchar and U.S. Sen. Al Franken, D-Minn., that Zika would be tough to eradicate if it spread in Aedes albopictus mosquitoes, localized "ankle-biters" that are tough to eliminate by spraying.

However, he said any outbreaks that do occur in the United States would be in isolated clusters.

The senators held the roundtable event following Thursday's Senate vote in favor of $1.1 billion in Zika prevention funding.

Public health officials have grappled with the proportionate response to Zika. Minnesota already has public health concerns such as mosquitoes carrying West Nile, ticks spreading Lyme disease and infected sexual partners quadrupling the rate of chlamydia cases since 1996.

And Osterholm has sounded the alarm about a yellow fever outbreak in central Africa. The World Health Organization on Thursday found the yellow fever outbreak wasn't yet a global emergency, but the mosquito-borne infection has a higher fatality rate than Zika.

"Yellow fever is not far behind," Osterholm said to Franken. "Yellow fever is going to make Zika feel like a bad cold."

The comedian-turned-senator paused and stared at Osterholm. "OK," he deadpanned. "The purpose [today] is not to scare me."