Female mosquitoes suck blood, spread Zika virus

Stephen Higgs, director of Kansas State's Biosecurity Research Institute, explains how female mosquitoes spread the Zika virus. The institute in Manhattan, Kan., is currently doing research into Zika.
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Stephen Higgs, director of Kansas State's Biosecurity Research Institute, explains how female mosquitoes spread the Zika virus. The institute in Manhattan, Kan., is currently doing research into Zika.
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K-State infects mosquitoes with Zika, hoping to unravel mysteries

By Rick Montgomery

rmontgomery@kcstar.com

July 29, 2016 06:23 PM

MANHATTAN, Kan.

In a laboratory room a few blocks from the football stadium, Kansas State University researchers are growing the dreaded Zika virus.

Downstairs in another room — that being the Mosquito Rearing Room — bugs are being hatched so the females can be given a Zika diet.

Scientists at K-State’s Biosecurity Research Institute hope to learn much from the process. Perhaps they can move science closer toward developing a vaccine that prevents human infections and the birth defects that can result.

Maybe they can figure out how to make the virus kill mosquitoes that carry it.

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On Friday, health officials said mosquitoes have apparently begun spreading the Zika virus on the U.S. mainland for the first time, a long-feared turn in the epidemic that is sweeping Latin America and the Caribbean.

Four recently infected people in the Miami area are believed to have contracted the virus locally through mosquito bites, Florida Gov. Rick Scott said.

No mosquitoes in Florida have actually been found to be carrying Zika, despite the testing of 19,000 by the state lab. But other methods of Zika transmission, such as travel to a stricken country or sex with an infected person, have been ruled out.

“Zika is now here,” said Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention.

Still, U.S. health officials said they do not expect widespread outbreaks in this country like those seen in Brazil, in part because of better sanitation, better mosquito control and wider use of window screens and air conditioners.

The K-State lab has more questions than answers about Zika, such as: Why doesn’t it seem to hurt mosquitoes and their offspring in the ways it can affect people?

“That’s one of the things we don’t understand,” said Stephen Higgs, the research institute’s director. “It doesn’t appear to alter (a mosquito’s) reproduction. It doesn’t seem to alter its behavior.”

We all could benefit, he said, if science knew how Zika-carrying mosquitoes travel, feed and survive compared to insects not infected. It would help to know more about how the virus is transmitted to humans and other animals, and why some mosquito species don’t spread it.

In K-State’s pursuit of answers, the Mosquito Rearing Room came into being just weeks ago.

The Biosecurity Research Institute converted a 200-square-foot maintenance area into a white-tiled place where a sign on the door reads, “Mosquitoes In Use.” Climate-controlled lockers hold mosquito larvae in water-filled containers. The conditions inside the lockers are set to replicate summertime, with fluctuating temperatures and light cycling into darkness as the day progresses.

Within days of hatching, adult mosquitoes are buzzing inside glass boxes called rearing cages, manufactured just for mosquitoes.

“We only infect the females because they take the blood meal” from people, said Dana L. Vanlandingham, an assistant professor in K-State’s College of Veterinary Medicine.

Peering into the rearing cages, Vanlandingham can distinguish the female mosquitoes from the males in an instant.

“That’s a female, that’s female, that one is a male. See?” she said, pointing to the bugs’ antennae.

The males’ antennae are bushier than those of the females.

Upstairs from the Mosquito Rearing Room, Higgs sat at a conference table alongside a plastic model of a mosquito. It’s the size of a Wal-Mart drone.

He said of Zika: “This is a virus we really don’t know much about.” He then flipped a latch on the bug model and opened it like a briefcase to explain what scientists do know.

Mosquitoes can contract the virus from infected people just as people get it from mosquitoes. On the model, he pointed to what he called the insect’s midgut, where Zika contracted from human blood produces millions of molecule particles.

Spreading throughout the mosquito’s insides, the virus ultimately reaches the salivary gland, where it becomes transmittable to humans, Higgs said. “Chances are, there’s going to be the virus in the mosquito’s spit for the rest of her life. That could be a few more days or maybe a few weeks.”

The K-State lab got its Zika virus from a Centers for Disease Control and Prevention facility in Fort Collins, Colo. The Biosecurity Research Institute is sharing the virus with the Maryland-based research company Bioqual Inc., where Zika is being tested on animals to study which species can be infected, said Bioqual president and CEO Mark Lewis.

Scientists around the globe are working swiftly to reacquaint themselves with a virus that had vanished for six decades.

As Higgs and Vanlandingham recently wrote in a paper published by the Royal Society of Tropical Medicine and Hygiene, Zika had been off researchers’ radar for more than half a century until 2007. That year, the mosquito-borne menace mysteriously reappeared on the Micronesian island of Yap.

It has since flown into the Americas. In Brazil, which next month is hosting the Summer Olympics, tens of thousands of residents and tourists have been infected. However, only about 20 percent of people who contract the virus show symptoms.

Higgs said that until a cure is discovered, the surest way to prevent infection is to avoid travel to areas where the virus has spread and to use repellants. “Pregnant women are particularly vulnerable,” he said.

As for the risks of the virus spreading from within the K-State lab, “standard operating procedures are designed to bring that risk down to zero,” Higgs said.

Vanlandingham has been researching mosquito-borne diseases since 1994 and has yet to be bitten on the job, she said.

“I’m more worried about my kids being out in the wilderness than I’m worried about working here,” she said.

The virus has triggered alarm across the Western Hemisphere’s warmer latitudes. While most people who get Zika don’t even know they are sick, infection during pregnancy can cause severe brain-related birth defects, including disastrously small heads.

More than 1,650 people in the mainland U.S. have been infected with Zika in recent months, nearly all while traveling abroad. Eight of those travelers came home to Missouri. Five are from Kansas.

The four people in Florida are believed to be first to contract the virus from mosquitoes within the 50 states.

The Associated Press contributed to this report.

Rick Montgomery: 816-234-4410, @rmontgomery_r