A few Zika-bearing mosquitoes could buzz into Iowa

Southern mosquitoes could buzz into Iowa this summer, but state experts don't expect them to be a major carrier of the Zika virus.

New maps from the Centers for Disease Control and Prevention show Iowa in the range of one of two mosquito species believed to carry the virus, which causes birth defects. The maps show the Aedes aegypti mosquito’s range petering out in Missouri, but they show the Aedes albopictus mosquito’s range extending through Iowa and into southern Minnesota.

Earlier CDC maps didn’t show either species being active here. Do the new maps suggest Iowans could be at serious risk from Zika-laden mosquitoes? Probably not, according to experts for the Iowa Department of Public Health and Iowa State University.

RELATED:

• What travelers need to know about the Zika virus
• Zika Q&A: What to know about efforts to fight the virus, conspiracy theories
• Complete Zika virus coverage

Ryan Smith, an entomology professor at Iowa State, suspects he’s partly responsible for the inclusion of Iowa in the new CDC map showing the albopictus mosquito's range. Smith said he filled out a CDC survey asking if either mosquito species had been found in Iowa. He answered yes, because the albopictus occasionally shows up in researchers’ mosquito traps.

“But it’s only been a handful in the last 15 years or so,” he said.

Smith said Iowa scientists haven’t focused in the past on trapping albopictus mosquitoes, which tend to fly during the day and are attracted to different things than more common Iowa species, including Culex mosquitoes.

The Zika virus’ main danger is it can cause serious birth defects if a pregnant woman is infected. The birth defects can include small heads and brains, which lead to lifelong disability.

His team plans to look more intently this summer for albopictus. They'll use special traps, including ones emitting carbon-dioxide gas from dry ice. The mosquitoes are drawn to carbon dioxide, which is exhaled by humans and other mammals. Once the insects get close to the trap, a fan sucks them in.

Smith said he would advise women who might be pregnant to reconsider traveling to countries where Zika is spreading. Women who need to go to such places for work or for an important family event would probably be all right if they take precautions against insect bites, he said.

“But if it’s somewhere you’re just going for vacation, maybe you should choose a different destination,” Smith said.

Patricia Quinlisk, medical director of the Iowa Department of Public Health, agreed with Smith’s travel cautions for women who might be pregnant. If such women go to affected areas, she said, they should consider using bed nets and insect repellent.

She acknowledged concerns about the effects of chemical repellents on unborn children, “but certainly that would be better than taking a chance on getting Zika.”

Quinlisk also noted Zika can be transmitted sexually. That’s why men who travel to affected areas are advised to abstain from sex or use condoms for at least eight weeks after they return, especially if their partners might be pregnant.

RELATED: Ames company to develop Zika virus vaccine

Iowa has recorded four confirmed cases of Zika infection so far this year, all in people who traveled to the Caribbean or Central or South America. Quinlisk doesn’t expect to see a major threat of transmission from mosquitoes in Iowa, even if a few albopictus mosquitoes wander up here. She said albopictus mosquitoes are believed much less likely to carry the virus than aegypti mosquitoes.

Quinlisk expressed optimism about a possible vaccine against the virus, although she said those shots could be years away. In the meantime, she said, other measures will help protect the public. For example, blood centers are asking people to wait four weeks to donate blood if they’ve recently visited Zika-affected countries. A test should be available soon to help assure the blood supply is free of the virus, she added.

Quinlisk said over several years, people’s immune systems could become accustomed to the presence of the Zika virus, which would dampen outbreaks. That’s apparently what happened in Iowa after the introduction of West Nile virus in 2001. Fourteen Iowans were sickened by that mosquito-borne virus last year, and none died. The peak year was in 2003, when West Nile sickened 141 Iowans and killed six.