Zika Defense: Hunting Mosquitoes That Transmit Virus

Feb 4, 2016

  Gov. Rick Scott has declared a health emergency in five Florida counties with a dozen confirmed cases of the travel-acquired Zika virus: Hillsborough, Miami-Dade, Lee and Santa Rosa.

Long before this most recent outbreak, mosquito control officers across Florida have been on the front lines, trying to keep at bay diseases such as Zika, chikungunya and dengue. 

Outside of a used tire shop off Orange Blossom Trail in Orlando, there are racks and racks of tires exposed to the weather – a favorite hiding spot for mosquito larvae.

In particular, Aedes aegypti and Aedes albopictus, commonly known as the yellow fever mosquito and the Asian tiger mosquito. These are the mosquitoes that can transmit Zika virus from person to person.

Amador Rodriguez, operations supervisor for Orange County Mosquito Control division, walks up to a tire that’s collected rain water. He uses a dipper, basically a cup at the end of a long stick, to get a sample.

“And we have some right here,” Rodriguez said.

The little black mosquito larvae wriggle around in the cup. They look like tiny tadpoles.

Kelly Deutsch, assistant manager of Orange County Mosquito Control Division, said it’s almost a guarantee that the larvae we’re looking at are one of the two breeds that can transmit Zika. That’s because the yellow fever mosquito and the Asian tiger mosquito love man-made structures: Tires, flower pots, garbage cans. Anything that can hold water in your backyard.

Florida Gov. Rick Scott declared a public health emergency in the four Florida counties with confirmed cases of travel-related Zika. Florida now has nine confirmed cases of travel-acquired Zika virus in Miami-Dade, Hillsborough, Lee and Santa Rosa counties. Scott’s order dictates public health officials to target residential neighborhoods with backpack mosquito spray measures.

But this kind of work, hunting and pecking for mosquito larvae, is the bread-and-butter of mosquito control all across Florida. Spraying to kill adult mosquitoes is a last line of defense. Going after the larvae – before they can transmit Zika – is a better approach, officials said.

The World Health Organization this week called Zika a public health emergency. The virus has been linked to a severe birth defect.

You might think of mosquito control as nuisance control. Not so, said Dr. Christopher Hunter, director of Orange County’s Health Services Department. Mosquito control is under the auspices of health services.
Orange County spends about $2 million a year on mosquito control, and workers inspected more than 29,000 sites last year.

“My opinion is yes, we’ll see [Zika],” Hunter said. “We see it with Dengue, with chikungunya, we see it with all these others, I think it will happen.”

Orange County has extra risk factors for Zika. One, the tourism industry brought in 1.9 million visitors from South America in 2014, where nine countries have active Zika transmissions.

But Central Florida is also home to large populations that have family in countries like Puerto Rico and Haiti. The worry is someone may spend a few weeks in a country with Zika and bring it back.

Dengue, chikungunya and Zika are all spread by the same mosquitoes, and those mosquitoes live in Florida year-round.

“Many of these are viruses that don’t have specific treatments,” Hunter said. “So the best way we can avoid people getting ill is controlling the vector, controlling the mosquito. From a public health perspective, it’s much simpler to control the mosquito population than the virus itself.”

Hunter said there’s a level of personal responsibility when it comes to the two breeds of mosquitoes that can spread Zika. People need to look for standing water on their property.

“These mosquitoes don’t travel far from where they breed,” Hunter said. “So if you have them in your yard or around where you live, they’re almost certainly breeding nearby.”

Reporter Abe Aboraya is part of WMFE in Orlando. Health News Florida receives support from the Corporation for Public Broadcasting.