Officials wary of new mosquito-borne virus
Published: Wednesday, July 2, 2014 at 3:14 p.m.
Last Modified: Wednesday, July 2, 2014 at 3:14 p.m.
The hot, humid, rainy summer months make for prime mosquito-breeding conditions, and this year health officials are warily watching a new virus.
Over the past several months, chikungunya, a painful, sometimes debilitating mosquito-borne virus, has spread from the Caribbean to the Southeast by way of infected travelers coming to the U.S. So far, Florida has been the hardest-hit state.
So far this year, 48 cases have been reported in the state, according to the Florida Department of Health's weekly mosquito activity report released last Tuesday. Each was travel-related, with no reported infections yet from a mosquito bite in Florida.
So far, there have been no reported cases in Alachua and Marion counties. Still, health officials say there is reason to be concerned that the virus will continue to spread.
Two mosquitoes transmit the virus. One of them, the Aedes albopictus, or Asian tiger mosquito, is the most common backyard mosquito in this area of the state and often feeds during the day, not the dawn or dusk times typically associated with mosquito activity.
"If you are out there during the day under an oak tree and there is a mosquito trying to bite you, this is that mosquito," said Phil Koehler, a professor of entomology at the University of Florida.
Given the Asian tiger mosquito's large population, it stands to reason that, as more infected people travel to the state, mosquitoes here could well begin to transmit the disease, Koehler said.
"The cases have been imported up to this point, but it's only a matter of time until mosquitoes attack a person who has the virus and then it spreads," he said.
Adding to the concerns in Florida and other areas of the country, World Cup host country Brazil is in the midst of outbreaks of both chikungunya and Dengue fever, a mosquito-borne illness with some similar symptoms.
There is "significant concern" that soccer fans returning to the U.S. from Brazil will further spread chikungunya, Alachua County Health Department Administrator Paul Myers said in an email last Tuesday.
Last week, U.S. Sen. Charles Schumer, D-N.Y., called on the Centers for Disease Control and Prevention to issue a health alert for doctors to be on watch for chikungunya in fans returning from Brazil.
While Eastern equine encephalitis and the West Nile virus are spread when a mosquito first bites a bird carrying the virus and then a human, people, not birds, are the "reservoir" or host for chikungunya, Myers said. "In order to maintain transmission of the virus, you have to have a concentration of people infected," Myers said.
To combat the spread of mosquito-borne diseases and hold down the mosquito population in general, health officials recommend steps to eliminate the most fertile breeding conditions: standing water.
Standing water should be emptied and avoided in tarps, bird baths, children's toys left outside, containers on the bottom of potted plants and even old tires left outside.
Protection is another step, Marion County Health Department spokesman Craig Ackerman said.
"What we're focusing on is for people to protect themselves," Ackerman said. "Wear long sleeves and long pants and use (insect repellent) DEET."
Chikungunya first appeared in the Caribbean in late 2013, following outbreaks in Africa, Asia, Europe, and the Indian and Pacific oceans, according to the CDC.
While watching for chikungunya, health officials are also monitoring the sometimes fatal Eastern equine encephalitis. So far, two horses in Marion County have tested positive. Last month in Alachua County, two sentinel chickens at a monitoring station in northeast Alachua County tested positive. Myers said those tests show the virus is active in the county and that residents countywide should take precautions.
Gainesville and Ocala both have active mosquito control programs. Peter Jiang, an entomologist with the city of Gainesville, said the first step is usually a larvicide treatment at breeding sites to kill larvae before they become adults. Spraying also is used to kill adult mosquitoes. Jiang described spraying as a "last resort."
Christopher Curry is a Gainesville Sun staff writer.