81ºF

'Zika killer' developed on University of Florida campus

Grad student, professors create trap for Zika-carrying mosquitoes

GAINESVILLE, Fla. – Concerns are certainly growing as a second suspected case of non-travel-related Zika virus was announced in South Florida -- meaning the people may have been infected in the United States, not out of the country. The Florida Department of Health announced Thursday evening it is now investigating a case in Broward County. Earlier this week, a suspected case was announced in Miami-Dade County.

The White House said President Barack Obama has been in contact with Gov. Rick Scott, offering financial and other support to investigate the origins and prevent future cases.

The answer to protecting people from Zika may be on the University of Florida campus. A graduate student and researchers have developed a weapon of sorts that may be the way to win the battle against the mosquito-born virus.

Entomology grad student Casey Parker helped professors create a mosquito trap, that is coated with a slow-release pesticide, to be used by homeowners in their yards. They actually started the project to battle other diseases transmitted by mosquitoes, but then Zika arrived.

"You put some water in the bottom of the trap. The female mosquito flies in when she's ready to lay her eggs," Parker said. "She lands on the surface of the trap and comes into contact with a lethal dose of pesticide. So when she flies away, she will eventually die. And if she does have the opportunity to lay her eggs, those eggs will never develop because of the pesticides inside the trap."

The pesticide is safe for humans, according to Parker, and will last up to 6 months -- a full mosquito season.

"The goal is to have people be able to buy them and use them around their home to protect themselves," Parker said. "We want people to be able to do their own pest control against these Zika vectors."

Parker and her professors originally started the project six years ago, to control the dengue and chikengunya vectors. The same mosquitoes that vector those diseases also vector Zika.

Their trap's colors are bold red and black, and its inventors joke at the UF facility that it's not a Georgia Bulldog theme. Actually, the contrasting colors are proven to lure in mosquitoes, and there's an attractant inside the trap that's like food to the insects.

Each trap could cover about 3,000 square feet, so some homeowners may want several of the traps to place in damp areas of their yard -- especially where rainwater tends to pool, near potted plants or pet bowls.

Aedes aegypti, which is commonly known as the yellow fever mosquito, is a known carrier of Zika. The other type of moquito that can carry the virus is known as Aedes albopictus, or the Asian tiger mosquito

Parker hopes to see the trap registered and available to the public.

"So they can practice their own mosquito control and hopefully, as a community, we can get the Aedes aegypti and Aedes albopictus problem under control," she said.

They say the pesticides they're using have been used in the pesticide industry for years. One is a synthesized form of a plant extract, and another has been deemed safe for drinking water by the World Health Organization.

Dr. Roberto Pereira, a research scientist in the UF entomology and nematology department, says the concern of Zika outweighs any worries some may have about pesticides.

"With this specific mosquito, the consequences are very, very harsh. So it's worth using a little bit of pesticides that are very safe, to control this mosquito," he said.

Pereira is from Brazil, and says Zika affects him very personally.

"I've had members of my family in Brazil that had dengue. It's a hard disease to go through but it doesn't have the consequences that Zika has," he said.

"I am holding the most dangerous animal in the world," said Dr. Philip Koehler, UF endowed professor of urban pest management.

He said the research is exciting and frustrating at the same time. They are finalists for a program to put the traps out in Honduras, to try to protect the people there, but they're still working to get the traps regulated by the U.S. government. He expects it will be a number of weeks, at least, until they could be mass produced.

"So we're a finalist for a grant to be able to put this out in other parts of the world," Koehler said. "Now, we haven't been successful in being able to get grants to try this even here in Florida, so it's been rather interesting, seeing that we have to go overseas in order to evaluate the product in the field."

Unlike previous warnings about mosquito-borne viruses, such as the West Nile virus, the mosquito that carries the Zika virus is a daytime flier. Anyone outside should wear repellent throughout the day, not just in the evening or early morning.

"They are aggressive daytime biters," Parker said. "They will actively pursue you during the day and they prefer to feed on humans over any other host."

Researchers at UF explain, in order to get local transmission, one of the travelers infected with Zika would have to be bitten by one of the carrier mosquitoes here in the U.S., and then that mosquito would have to feed on another human.

Follow Zika cases and Zika information in Florida on the Department of Health's website.

With no vaccine for the Zika virus and no drug to treat Zika infections, it has become clear that avoiding mosquito bites is essential. Consumer Reports has done the following investigations, trying to help consumers keep their families safe.

Clothing that's claimed to ward off mosquitoes

Manufacturers of special permethrin-treated clothing promise it will protect from mosquitoes. Permethrin is a chemical insecticide approved by the Environmental Protection Agency against a wide range of insects -- everything from ticks to mosquitoes.

L.L. Bean and ExOfficio say their shirts will repel mosquitoes and other bugs for up to 70 washings. The shirts don't come cheap, costing more than $70 each.

Consumer Reports tested to see how well the shirts prevent mosquito bites, both when new and after being washed 25 times. Volunteers put their arms into cages containing 200 mosquitoes. The permethrin-treated clothing did stun or kill many mosquitoes that landed, but none was foolproof in preventing mosquito bites.

The volunteers were not bitten when wearing the new L.L. Bean shirt, but after the shirt had been washed, Aedes mosquitoes that can carry the Zika virus bit three out of four testers. With the ExOfficio shirts, both new and washed, all four testers received bites from the Aedes mosquitoes as well as from Culex mosquitoes, which can carry the West Nile virus.

Consumer Reports contacted Burlington and Inspect Shield, the companies that make the permethrin treatment. Both cited formal studies and field testing data to underscore the effectiveness of their products. And a government expert says the clothing can reduce the number of mosquitoes in the immediate area.

There is another way for people to protect themselves, according to the Centers for Disease Control and Prevention. Any repellent that works on skin should work for just as long when applied to clothing.

Insect repellents to help keep you safe

Consumer Reports tested 16 insect repellents for their effectiveness at repelling bites from the Aedes mosquitoes that can carry the Zika and Chikungunya viruses and the Culex mosquitoes, known to spread West Nile virus. The lab also tested the repellents against deer ticks, which can carry Lyme and other diseases.

Some of the repellents are labeled "natural," and contain plant-based oils. But Consumer Reports found they were not very effective. Five out of the six that were tested lasted only an hour and a half or even less against the Aedes mosquito, the one that carries the Zika virus.

In response to Consumer Reports' concerns about natural insect repellents, a trade group, the Natural Products Association, says that some plant oils do work, and some people want alternatives to DEET.

The only "natural" repellent that did a good job was Repel 30 percent Lemon Eucalyptus. It was able to ward off Aedes mosquitoes for 7 hours. It should not be used on children under 3 years old.

Other repellents that did well in Consumer Reports tests were Sawyer 20 percent Picaridin and Ben's 30 percent DEET Tick and Insect Wilderness Formula.

When used properly, they are safe for children and all are safe for women who are pregnant or breast-feeding.

Here is more advice from Consumer Reports on buying insect repellents.
 


About the Authors: