Ohio’s hot and dry summer is giving a boost to the mosquito that carries the West Nile virus and increasing the risk to Ohio residents.
The number of mosquito samples testing positive for the virus is on the rise, according to the Ohio Department of Health.
So far, the virus has been found in 213 samples across Ohio this summer. This is up from 104 instances a week ago, according to state records. Last year at this time, Ohio had only 38 positive mosquito samples.
The West Nile virus threat is the greatest since 2002, another summer that favored the Culex mosquito that carries the virus, said state spokeswoman Tessie Pollock.
In 2002, Ohio had 31 deaths and 441 human cases of the virus.
The Culex mosquito thrives in hot and dry conditions.
The number of mosquito samples with the West Nile virus usually climbs in late summer, but is not usually this high in July, she said.
Neighboring states are reporting similar results, indicating that the West Nile problem could be spread across the Midwest this summer.
Eleven of the 14 Ohio counties that conduct mosquito surveillance have had positive results, including districts in Summit and Stark counties, Pollock said.
The Summit County Health District has reported 11 positive samples. That includes five new cases.
Nearly all of the spraying undertaken this year is because of the West Nile threat, said spokesman Terry Tuttle.
In 2011, Summit County had 104 positive samples, a higher-than-usual total, he said.
Hot weather plays part
The warmer-than-usual temperatures have a big impact on mosquitoes, he said. They tend to be more active, bite more and breed faster when it is hot, he said.
The Barberton-Norton Mosquito Abatement District was notified on Friday of nine new mosquito samples with the virus: five in Barberton and four in Norton, said spokesman Jeff Stewart. Previously, the district had two positive samples, both in Barberton.
This has triggered increased spraying in affected neighborhoods, he said.
The Stark County Health Department has 10 West Nile hits, all from last week’s mosquito tests. The Canton Health Department has had 11 positive samples, including seven new cases.
Franklin is No. 1
The No. 1 West Nile hot spot in Ohio is Franklin County, where 112 samples have tested positive for the virus. No. 2 is Montgomery County, with 31 positive samples.
Other counties with positive samples are Cuyahoga, Delaware, Hamilton, Lake, Licking and Lorain.
To date, Ohio has collected 99,128 mosquitoes. Of that number, 91,512 have been tested, usually in batches of 50. A total of 2,760 samples or pools have been tested and another 149 samples are pending.
Last year at this time, Ohio had collected 171,167 mosquitoes with only 38 positive samples.
At the end of 2011, Ohio had tested 290,840 mosquitoes and found 586 positive samples. There was one death: a 78-year-old New Franklin man who died in September. It was the first West Nile death in Ohio since 2008. Summit County’s first fatality was in 2002.
To date, Ohio has had no human West Nile cases this summer. But the virus was detected in one donated blood sample.
Public health experts estimate roughly 20 percent of people infected with the virus develop West Nile fever, which typically causes fever, headaches, tiredness and body aches and occasionally causes a skin rash and swollen lymph glands.
About one in 150 people infected with West Nile virus develops a more severe form of disease, such as West Nile encephalitis or meningitis, according to the U.S. Centers for Disease Control and Prevention.
Symptoms of severe disease include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.
People older than 50 and those with compromised immune systems are at the highest risk for becoming severely ill. according to medical experts.
Ohioans are advised to use insect repellent with deet, wear long sleeves and long pants, avoid outdoor activity at dawn and dusk and eliminate standing water around the house where mosquitoes may breed, said Pollock and Stewart.
Bob Downing can be reached at 330-996-3745 or firstname.lastname@example.org.