Zika (not) in Minnesota: What you need to know

The mosquitoes that transmit Zika virus are not established in Minnesota, so the risk of acquiring the disease here is extremely low.

But travelers headed to outbreak zones should take precautions.

Has the Zika virus arrived in Minnesota yet?

More than thirty Minnesotans have returned to the state from outbreak areas with the infection and health officials say that number will continue to grow. But those people do not represent a significant risk to anyone but their sexual partners.

More importantly, the mosquitoes that can carry and spread the Zika virus don't live here and the virus has never been found in mosquitoes here.

Some mosquitoes capable of carrying the virus have been found in the southern part of the state on occasion, but it's nearly impossible that they would carry the virus.

Since 1991 small populations of Asian tiger mosquitoes, also known as Aedes albopictus, have been detected a total of 17 times.

Asian Tiger mosquitoes are typically found in Minnesota near commercial tire recycling businesses. It's likely the mosquitoes hitch a ride to Minnesota in old tires during their larval stage.

Standing water in old tires is a magnet for breeding mosquitoes. Then the larvae hatch after arriving in Minnesota.

But since there's no sustained presence of Zika in the state, it's highly unlikely the adult moquitoes would ever pick up the virus.

And they've only been found during the summer in Minnesota. State mosquito experts don't think Aedes albopictus eggs could survive a Minnesota winter, but they recently expanded their surveillance efforts to include a half dozen southern Minnesota cities where it might be warm enough for the insects to eventually gain a foothold.

The primary carrier of Zika virus has never been found in Minnesota. The Aedes aegypti mosquito, also known as the yellow-fever mosquito, dwells in tropical and sub-tropical areas. It can't withstand Minnesota's cooler temperatures. But during the summer months it could also hitch a ride here in old tires and containers.

So is it possible to get Zika from one of these mosquitoes in Minnesota?

Yes. But your risk is almost nil.

Mosquitoes only acquire the virus from the blood of an infected person.

Travelers infected with Zika typically clear the virus from their blood quickly; within a week or two.

Minnesota Department of Health epidemiologist Dave Neitzel says for Zika to spread locally, an infected traveler would need to encounter the right kind of mosquito during a very narrow window of opportunity.

"During the short period of time when they have virus circulating in their blood, they'd need to be bitten by mosquitoes that could maintain and then further transmit this virus," said Neitzel. "And that's what's very unlikely in this state."

Reducing the odds further is the fact that both of these mosquito species tend to be homebodies. They rarely venture more than a few hundred feet from where they hatch.

So Neitzel says as long as imported mosquitoes appear primarily in commercial sites, where they are trapped and destroyed, they shouldn't come into contact with many people.

How concerned should I be about Zika, if I'm traveling to an outbreak area?

Zika doesn't cause major health problems for most people. But public health officials want to limit the virus' spread because Zika can be passed from a pregnant woman to her fetus and it can cause devastating birth defects.

Brazil has confirmed more than 1,700 infected babies have microcephaly, a life-threatening condition that results in an abnormally small head and severe brain damage.

The U.S. Centers for Disease Control and Prevention urges pregnant women or women who plan to become pregnant soon to avoid travel to outbreak areas or take precautions to prevent mosquito bites if they must travel.

The CDC says people who have traveled to a Zika outbreak area and have a pregnant sex partner should consistently and correctly use condoms to prevent infection during sex or avoid having sex for the duration of the pregnancy.

Zika can remain in semen for several months. Women who are infected with the virus can also pass it to their sexual partners.

What are the symptoms of Zika?

Zika typically causes mild illness that can include a fever, rash, red eyes and joint pain. But many people won't experience any symptoms. That's one reason it's hard to control the spread of the virus.

Zika infrequently leads to a debilitating nervous system condition called Guillain-Barré syndrome. People who develop GBS experience muscle weakness and even paralysis. Most people recover, but it can take weeks or months.

Is there a Zika vaccine?

Currently there is no vaccine to prevent Zika or medicine to treat it. Congress has not approved new funding to fight the virus, so federal agencies are diverting funds from other programs to continue work on vaccine candidates.

Some early safety trials have begun, but the process requires many regulatory steps. The earliest a vaccine could be available would be 2018.