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On the Ground With Scientists Battling Zika in Florida

When state officials announced last week that they'd captured mosquitoes infected with Zika, it was by using these scientists' traps.

by Meredith Rutland Bauer
Sep 9 2016, 2:30pm

Ingeborg Cuba, a USDA entomologist, subjects her arms to mosquito bites to test the bug repellent on a new form of military cameo sleeves. Image: Meredith Rutland Bauer

Editor's Note: This is the first of two stories about Florida's attempt to control the Zika virus.

Ingeborg Cuba, a USDA researcher, swiftly stuck her arms into boxes swarming with 200 mosquitoes. It was late August, and after a particularly intense summer, she knew the work done at this US Department of Agriculture mosquito lab could help her pregnant friends in Miami.

Back in July, Florida became the first state to be hit by locally transmitted Zika, a mosquito-borne virus that can cause severe brain damage, especially in developing babies, according to the Florida Department of Health. The environment here makes it an ideal breeding ground for the virus, which has spread locally in the state to 43 people as of Sept. 8. But it still caught everyone by surprise in Miami-Dade and Pinellas counties, and the cases continue to stack up, with eight more reported this month, according to the CDC.

Now, while the federal government continues to delay the release of $1.1 billion in funds to fight Zika, Florida's communities and institutions have stepped up to the challenge, from the streets of Miami to university laboratories.

USDA entomologist Dan Kline stands by a mosquito trap, center, in an environment set up to mimic a South Florida backyard. Image: Meredith Rutland Bauer

Cuba's friends and family didn't always understand why she wanted to study mosquitoes earlier in her career. Now, with Zika in their backyards, they see how a tiny insect can grip the attention of a nation.

"They start to see how scary this bug really is," Cuba said, her arms surrounded by tiny, sterile swarms.

At the US Department of Agriculture Center for Medical, Agricultural and Veterinary Research in Gainesville, Florida, researchers like Cuba breed 10 types of mosquitoes—the world's worst offenders when it comes to spreading fatal or deforming diseases, the entomologists told me.

Prior to the outbreak, there wasn't enough funding to get the mosquitoes under control in Miami-Dade County, which is home to about 2.6 million people. The problem was exacerbated when Florida's Governor Rick Scott slashed statewide funding for mosquito control districts in 2011 by 40 percent—from $2.16 million to $1.29 million, according to Politico.

But after Zika cases started trickling in, Scott dedicated $26.2 million in June to stopping Zika, the governor's office stated. Florida politicians are urging the federal government to pitch in to squash the virus faster. US Rep. David Jolly, who represents Pinellas County, brought a jar of Aedes aegypti mosquitoes to the House floor this week to help Representatives visualize the issue, but they have yet to approve the bill.

The Aedes aegypti mosquito. Image: USDA/Flickr

"Can you imagine, colleagues, the fear and anxiety in this chamber if these 100 mosquitoes were outside this jar, not inside this jar?" Jolly said in his House address. "The time for the politics of Zika is over. The politics of Zika are garbage right now."

The Zika virus can be spread by two types of mosquitoes and through sexual contact, but it largely relies on Aedes aegypti, the same culprit behind dengue and yellow fever. This type of mosquito is as common as a summer's day puddle—where their lives often begin.

The researchers at this USDA lab in Gainesville have been studying Aedes aegypti for years, and their focus has intensified in the wake of Zika's spread. And the more the researchers learn, the more they hate this strange bug.

Mosquitoes usually breed in large, stagnant pools, hunt during dusk and dawn and fly around in plain sight. But Aedes aegypti are a sneaky enemy. They fly low to the ground, biting ankles and flitting away. They hunt day or night. And unlike most other types of mosquito, they've adapted to live alongside humans, specifically hunting out human blood. They can also go entire generations without leaving someone's home, said Dan Kline, a USDA entomologist.

"You hit their closet, and all these mosquitoes come flying out," he said, describing his work internationally fighting the mosquito. "Thailand, Brazil—it's an indoor mosquito."

Dan Kline with a sheet of Aedes aegypti eggs, each the size of a period. Image: Meredith Rutland Bauer

Kline led me around the Gainesville lab last month, wrestling open a sealed door inside a lab prep room. Stacks of pale plastic bins lined the walls, and a dank, oppressive smell made me feel like the air around me just got heavier. "Ammonia," Kline explained.

The containers are faux swamps, and they hold developing larval mosquitoes. Some will grow up to be adult mosquitoes which are used to test pesticides and repellants, and others will be used to test how well larvicides, which are pesticides that kill juvenile mosquitoes, work on various species.

Kline said the lab also works on testing mosquito traps. Traps are mostly used by pest control regulators and scientists to wrangle up local bugs to test for certain viruses. When state officials announced last week that they'd captured mosquitoes infected with Zika, it was by using these traps.

The current traps rely on colors and manufactured attractants (mostly chemical mixes meant to emulate human sweat and breath) to funnel the mosquitoes into a vacuum. But researchers at this lab and at others are also working on cutting-edge traps—ones that may eventually help the world's poorest families to weed out mosquitoes.

Aedes aegypti usually lay the eggs in multiple spots. And they lay their eggs just above the waterline of any small container, rather than in the shallows of stagnant ponds like most mosquitoes. The eggs can survive unhatched for a dry summer or a cold winter. One brisk shower is enough to hatch them into larvae within minutes—within a week, they'll be mature and biting.

Hundreds of mosquitoes swarm inside a holding container inside a USDA lab. The mosquitoes are fed meals of sugar cubes and blood. Image: Meredith Rutland Bauer

"It could be be bottle caps, discarded cups. It could be snail shells. It could be coconut husks," Roxanne Connelly, University of Florida entomology professor and entomology specialist for a statewide agricultural network, told me. "It could be literally anything."

This means scientists are left to fight and trap an almost-invisible enemy. Any speck of dirt can be a tiny Aedes aegypti egg. Any dark corner can hold a Zika-infested mosquito. Any hint of a raincloud can be a harbinger of disease. But if a specific flower is around, they'll lay nearly all of their eggs on that flower. Similarly, traps have long used carbon dioxide and other chemicals mosquitoes use to track down humans.

Read more: How Canadian Scientists Plan to Fight Zika With Old Tires and Milk

Kline has started to learn their game. He recently discovered that the mosquitos love smelly socks by conducting an experiment where he put 200 mosquitoes in a box and baited a trap with carbon dioxide and a smelly sock. "I got 199," he said, smiling. Researchers are now working on ways to make these habits fatal to the mosquitoes.

Outside the USDA lab, Kline and I sloshed our way through wet grass toward a mosquito trap testing area. The story-high screened-in rectangle seems out of place by the red brick buildings. The Army tent inside is even more jarring. Next door, bug screens surround lines of hedges and a white-roofed pergola.

An Army tent sits in a screened-off area outside a Gainesville, Florida where scientists test repellants, USDA lab. Image: Meredith Rutland Bauer

Researchers have to test the traps, repellents and pesticides in various environments. Decades ago, one of these areas held a jungle environment when the lab was preparing materials for Vietnam soldiers. Now, they're set up like a typical South Florida backyard.

The traps will mostly be used to see how many mosquitoes are in an area, and whether they have Zika—a sort of entomological census. Kline often tests new products from different companies, to see if they're better than what the federal government is recommending.

If the traps become really good, people might one day be able to set them inside their homes like ant traps. But for now, he said, bug spray and a fly swatter are still the better weapons.

And there's still no better bait than a human arm.