Braxton Davis said he sometimes dreads going outside to play with his 4-year-old son because of all the mosquitoes he knows he’s going to encounter.
No matter what he does, Davis said, he can’t seem to avoid bites from the pesky insects — and the soreness and itchiness that follows.
“The mosquitoes have been out of control,” he said. “It’s made going outside an absolute disaster.”
Climate trends are causing mosquitoes to appear earlier in the spring and stick around later into the fall, researchers say.
The homeowners association for Davis’ Midtown neighborhood had suspended use of the private mosquito control spraying it paid for in recent years because it didn’t believe the effort was working. This summer the bugs have been so bad it had to re-up the service.
But consistent rain in the Atlanta area has made it difficult for the insecticides to do what they need to do — and also allows the mosquitoes to breed more easily.
Because the planet is currently experiencing warmer temperatures for more days of the year, mosquitoes are around for longer chunks of time, scientists say.
“Seasonal insects typically don’t fly or aren’t very active until it’s 50 degrees or more Fahrenheit,” University of Georgia entomologist Elmer Gray said. “As that shifts a little bit each year, or as it’s shifting, obviously insects are going to be a little more active.”
More warm days
In Georgia, Department of Public Health officials track mosquito season by monitoring when nighttime temperatures are consistently above 50 degrees. However, other factors affect the season, including daytime temperatures, humidity, rain, places to breed and the types of mosquito species in the area.
State health officials said the early warm weather this year followed by a cold snap led to a slower start to the mosquito season. But if it takes longer for it to cool down in the fall, mosquitoes will stick around longer, Gray said.
“An area of particular concern could be prolonged or higher overnight temperatures,” he said. “In the fall, as soon as it starts cooling off, mosquitoes start dropping off.”
It’s hard to track the number of days of the mosquito season of any year, researchers say.
Michael Reiskind, a professor of entomology at North Carolina State University, said it generally makes sense that warmer weather will lead to more mosquitoes.
“But it’s been difficult to look at weather patterns and say what it means for the abundance of mosquitoes,” he said.
It’s an area that’s not very well studied yet, said Sadie Ryan, a medical geography professor at the University of Florida.
“Big, rich cities have more money than county districts in the same state may have,” she said. “It makes it complicated to study in a systematic way.”
Spreading disease
Anecdotally, researchers say they believe the season is lasting longer — leaving more opportunity for mosquito-borne illnesses to be passed to humans. That should be a concern to many Georgians during the peak West Nile virus season, which runs from Aug. 15 to Sept. 15, Gray said.
The Georgia Department of Public Health, as of Monday, had confirmed four cases of West Nile virus in humans this year. According to data from the U.S. Centers for Disease Control and Prevention, there were 48 reported cases in 2017, a drastic jump from the six reported the year before.
A recent report by Climate Central, a group that studies climate change, found that the warming climate is also increasing the number of "mosquito disease danger days" — when there is a higher risk of humans being infected.
Research shows that viruses are more likely to be transferred to humans when temperatures are between 61 degrees and 93 degrees Fahrenheit, according to the study.
Climate Central found that Atlanta temperatures in 2017 provided nearly 210 mosquito danger days, which is 15 more days than in 1970.
“If you’re living in an urban environment, rain patterns can mean more standing water, so more breeding, and it means that you have to be vigilant for more of the year as temperatures continue to get warmer,” Ryan said.
Staying safe
State health officials say the best way to prevent mosquito bites is to observe the “Five D’s”:
- Dusk/Dawn — Mosquitoes usually bite at dusk and dawn, so avoid or limit outdoor activity at these times.
- Dress — Wear loose-fitting, long sleeve shirts and pants to reduce the amount of exposed skin.
- DEET — Cover exposed skin with an insect repellent containing DEET, which is the most effective repellent against mosquito bites.
- Drain — Empty any containers holding standing water because they can be excellent breeding grounds for virus-carrying mosquitoes. Like candidates include flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires and birdbaths.
- Doors — Make sure doors and windows are in good repair and fit tightly, and fix torn or damaged screens to keep mosquitoes out of the house.
Davis said it has gotten to the point where, other than accompanying his son to the baseball and soccer games when his 4-year-old is playing, he and his family spend more time indoors.
“If we want to sit on the porch, we might light a citronella candle,” he said. “But we actually haven’t sat on the porch much lately. When I look out there I see swarms of mosquitoes.”
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