'Little ninja': Zika-spreading mosquito puts up tough fight

MIAMI -- The mosquitoes spreading Zika in Miami are proving harder to eradicate than expected, the nation's top disease-fighter said Tuesday as authorities sprayed clouds of insecticide in the ground-zero neighborhood, emptied kiddie pools and handed out cans of insect repellent to the homeless.

Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, said the mosquito-control efforts in the bustling urban neighborhood aren't achieving the hoped-for results, suggesting the pests are resistant to the insecticides or still are finding standing water in which to breed.

"We're not seeing the number of mosquitoes come down as rapidly as we would have liked," he said.

Mosquito-control experts said that's no surprise to them, describing the Aedes aegypti mosquito as a "little ninja" capable of hiding in tiny crevices, sneaking up on people's ankles and breeding in just a bottle cap of standing water.

Fifteen people have become infected with Zika in Miami's Wynwood arts district, officials said Tuesday. These are believed to be the first mosquito-transmitted cases in the mainland U.S., which has been girding for months against the epidemic coursing through Latin America and the Caribbean.

On Monday, the CDC instructed pregnant women to avoid the neighborhood, marking what is believed to be the first time in the agency's 70-year history it warned people not to travel somewhere in the U.S.

The Zika virus can cause severe brain-related defects, including disastrously small heads.

At the same time, U.S. health authorities have said they don't expect major outbreaks in this country, in part because of better sanitation and the use of air conditioners and window screens.

On Tuesday, Miami-Dade County mosquito-control inspectors toting backpack blowers released white clouds of bug spray in Wynwood.

They also went door to door, handing out information, checking tires and other objects for standing water and dipping cups to take water samples from vacant lots, building sites and backyards.

In one lush yard, an inspector tipped over a kiddie pool and a cooler full of water.

Daily aerial spraying for adult mosquitoes and larvae has been approved for the next four weeks over a 10-square-mile area around Wynwood, county officials said.

The city of Miami said it is running more street sweepers in Wynwood to remove the litter and stagnant water that can serve as breeding grounds, and police officers handed out 50 cans of bug spray to homeless people in the neighborhood.

"Be sure that you use it," officer James Bernat said as he gave repellent to several people who had been sleeping on the street.

Dozens of pregnant women streamed into Borinquen Medical Center, a clinic just outside Wynwood where doctors said they were getting more and more nervous requests for Zika testing.