Thursday, July 16th, 2015
Record rains produce bumper crop of mosquitoes
By Shelley Grieshop
The rainy summer is swelling the mosquito population and boosting the risk of contracting the diseases they carry.
Flooding can leave behind pockets of water that create the perfect egg-laying habitat for mosquitoes infected with diseases such as West Nile virus - the most common illness carried by the insects in the U.S.
"Culex pipiens (common house mosquito) ... are one of the main species associated with West Nile virus, and they tend to breed more in containers where the water is stagnant," Dr. Richard Gary, an Ohio Department of Health entomologist, told the newspaper this week. "Don't let water sit around."
Old tires, bird baths, gutters and hot tub covers are a few of the items that often hold water for longer periods of time and attract breeding mosquitoes, he said.
Mosquito eggs can be laid in batches of 50 to 400; one female can lay several batches. The eggs often are prompted to hatch after a heavy rainfall, health officials said.
Nearly 13 inches of rain fell in the Celina area in June - almost 10 inches more than average. July also has been soggy with nearly 6 inches recorded so far.
"There is more mosquito activity now than we've seen at this time of year for several years but still much lower than in our West Nile virus outbreak years of 2002 and 2012," ODH Medical Director Mary DiOrio said.
No cases of the West Nile virus in humans have been confirmed in Ohio this year. Eleven were reported statewide in 2014.
Mercer County has confirmed four cases of West Nile virus in humans since 2006; three of the cases occurred in 2012. Auglaize County has recorded two cases since 2006, according to ODH.
Most people infected with West Nile virus have no symptoms. About one in five will develop a fever, headache, bode ache, joint pain, vomiting, diarrhea or rash. Less than 1 percent develop a serious neurological illness.
Encephalitis is another serious disease transmitted by mosquitoes that can cause brain inflammation.
ODH recently announced that five of its mosquito pool sites across the state tested positive for West Nile virus. The locations are in Columbus and Franklin, Richland, Summit and Licking counties.
Michelle Kimmel, director of environmental health in Mercer County, said it's been a challenge finding local places for mosquito pool trapping. She's in the process of helping several ODH interns complete the work, she said.
"They use a plastic tub filled with an awful-smelling liquid ... to attract the more nuisance mosquitoes," Kimmel said. "They usually set them out overnight and go back and get them in the morning."
The samples are then taken to an ODH laboratory in Columbus, she said.
"If any test positive for West Nile virus, it gets reported by the state," she said.
An initial round of testing was completed locally several weeks ago with no positive results, Kimmel said.
"Now we're looking to do more in wooded and wetland areas," she said, adding she's recommending a site near a construction and demolition debris business where standing water has been observed in the past.
Curt Anderson, director of environmental health in Auglaize County, said mosquitoes are most active certain times of the day.
"The mosquito species that carries West Nile virus tends to be most active at night and early in the morning so if you can avoid being out at that time, do so," he said.
The use of bug repellant containing Deet is the best way to prevent annoying mosquito bites and the diseases they carry, Kimmel said.
"Wear repellant. I think that's the most realistic, easy thing to do," she said.
Tips to prevent mosquito bites:
• Wear EPA-registered mosquito repellants when the insects are present and follow label instructions.
• Wear long, loose and light-colored clothing, if possible.
• Install or repair screens on windows and doors to keep the insects out.
To reduce mosquito breeding on your property,
• remove temporary pools of water, clear debris from ditches, cut small channels to allow pooling water to drain and fill in holes and tire ruts with dirt.
• keep children's wading pools empty and on their sides when not in use.
• empty standing water from flower pots, gutters, buckets, pool and hot tub covers, pet water dishes, discarded tires and bird baths.
- provided by the Ohio Department of Health
