Valley flooding means millions of mosquitoes, growing Zika concerns

Posted at 7:14 PM, Aug 03, 2016
and last updated 2016-08-03 22:38:53-04

Flooding in the Phoenix area is causing big concerns about a mosquito explosion that could increase risks for the Zika virus.

A bottle cap full of water is all it takes to breed and hatch mosquitoes. Maricopa County Vector Control experts are keeping a close eye out for disease-carrying mosquitoes that are likely to pop up by the millions, thanks to standing flood water all around the Valley.

Vector control has roughly 800 traps out around the county. They catch, count and test mosquitoes for all kinds of diseases – including Zika. So far, no mosquitoes have tested positive for the Zika virus in Maricopa County.

Zika is the virus capable of causing severe birth defects in pregnant women. It has mainly been found in foreign countries, but recently popped up in the U.S., with local transmissions in Miami. 

The mosquito capable of causing Zika, the Aedes aegypti, is common in Arizona.

“Those Aedes aegypti will be actually be breeding in just little bits of water in people's backyard,” said John Townsend, of the Maricopa County Vector Control.

Townsend said the Aegypti mosquito eggs take about four days to hatch in standing water-- that means any water not dumped almost immediately after a storm could quickly become a breeding ground for the potentially dangerous bugs.

“Being bitten down low around your feet and ankles during the daytime, those are almost always Aedes aegypti,” Townsend said.

While Zika hasn’t been found in Arizona mosquitoes, an outbreak could happen if someone infected with the virus comes to the state and is bitten by an Aegypti mosquito. The infected mosquito would also need to then bite another human to spread the disease.

“They don't go very far. If we ever had a problem with any kind of local transmission, it would be within the backyard and maybe the surrounding houses around there,” Townsend said.

Right now, vector control is finding the most mosquitoes in the east Valley. Mosquitoes from 56 of their traps have tested positive for West Nile Virus. Vector control agents fog any area with large mosquito populations or positive disease testing.