By Julie Steenhuysen
CHICAGO, Sept 1 (Reuters) - Hurricane Hermine, set to cause flooding and damage when it hits Florida overnight, will make it harder for the state to fight Zika, a mosquito-borne virus shown to cause birth defects, experts in infectious diseases and mosquitoes said on Thursday.
Forecasters are warning of potentially life-threatening storm surges and as much as 20 inches of rain. Governor Rick Scott declared a state of emergency in most of Florida's 67 counties ahead of the first hurricane to strike the state in more than a decade.
Once Hermine passes, the remaining water "will provide all kinds of breeding sites for the mosquitoes," that can spread Zika said Dr. William Schaffner, a professor of Infectious Diseases at the Vanderbilt University School of Medicine in Nashville.
The hurricane is also likely to disrupt mosquito abatement activities as state authorities prioritize other emergency efforts. On Thursday, Florida officials said they had trapped the first mosquitoes shown to have the Zika virus after weeks of searching. Schaffner said the finding showed there is a substantial amount of Zika in circulation.
"People around their homes will be worried about themselves and their families and neighbors rather than looking for mosquito breeding sites," Schaffner said. "Emergency responders will be focused on things other than mosquito abatement."
Florida is the first state in the continental United States to confirm local Zika transmission, with 47 cases of infection so far, raising concerns among pregnant women and threatening the state's multibillion-dollar tourism industry.
First detected in Brazil last year, Zika can cause the rare birth defect microcephaly, marked by abnormally small heads and underdeveloped brains, when pregnant women are infected. Brazil, has confirmed more than 1,800 cases of microcephaly since last fall.
Earlier this week, Scott urged residents and business owners to remain vigilant against Zika-carrying Aedes aegypti mosquitoes once the storm had passed. Scott and other state officials have stressed the need to dump standing water and take other steps to eliminate breeding areas.
High winds from the hurricane will also make aerial spraying with pesticides impossible, disrupting a key effort by the state to keep mosquito populations under control, said Joseph Conlon, a retired U.S. Navy entomologist who serves as technical adviser for the American Mosquito Control Association.
"If it's raining or if the winds are above five to 10 miles per hour, aerial spraying is out," said Conlon, who lives in Jacksonville, Florida.
Conlon said initially, high rains will likely wash out a lot of mosquitoes, but if flood waters leave behind debris, that could provide breeding sites for the mosquitoes that carry Zika.
"It will make for more mosquitoes, there's no doubt about that," he said.
Aedes aegypti mosquitoes can lay their eggs in small pools of standing water no bigger than the size of a bottle cap. The eggs cling to the edges of containers and can survive long droughts.
Florida officials have been working to drain water in containers on residents' property and scrub away rings of eggs, but fresh rains from a large storm could refill them, and any remaining eggs could hatch.
"If you can't get rid of the water source, scrub the insides of containers to get rid of the eggs," Conlon said.
Conlon said the storm will also likely hatch hoards of flood water mosquitoes that present a nuisance, but do not carry disease.
(Reporting by Julie Steenhuysen; Editing by Michele Gershberg and Andrew Hay)
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