High temps raise threat of West Nile virus cases
By ERIC SCHELKOPF
For the past two years, cool spring temperatures helped slow the spread of West Nile virus.
But local and state health officials are warning that this summer could be different because of the wet and warm spring the area has been experiencing.
Culex mosquitoes – the species most commonly associated with the disease – crave hot weather and stagnant water. The virus is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird.
“We’ve been lucky the last two years because cool spring temperatures have helped to slow the spread and keep our case counts down,” said Paul Kuehnert, Kane County Health Department’s executive director.
Kane County saw no human cases of West Nile virus last summer and there were only five cases reported across the state. In 2008, Kane County had three human cases.
In comparison, Kane County had 13 human cases in 2007. That August saw warm temperatures and flooding.
This spring has been warmer and wetter than normal. According to the National Weather Service, the period from May 1-13 was the sixth wettest on record since 1871.
March, April and May all have been warmer than usual, said National Weather Service meteorologist Charles Mott. But the long-range forecast calls for below normal temperatures in June, July and August, Mott said.
However, that forecast is not set in stone, he said.
“It gets updated all the time,” Mott said. “It could change.”
Only about two people in 10 who are bitten by an infected mosquito will experience any illness. Illness from West Nile is usually mild and includes fever, headache and body aches, but serious illness, such as encephalitis and meningitis, and death are possible, according to the Illinois Department of Public Health.
People older than 50 have the highest risk of severe disease.
“Their immune systems are beginning to weaken at that age,” said Kristen Nordlund, spokeswoman with the Centers for Disease Control and Prevention.
“They are more susceptible to infection.”
Nordlund said it’s too early to say how much of a danger West Nile virus will pose this summer.
“Most cases occur in August and September,” she said.
West Nile virus was first discovered in the United States in the summer of 1999 in New York.
Since then, the virus has spread throughout the United States.
There are measures that residents can take to help prevent West Nile virus, such as avoiding being outdoors at night when mosquitoes are most active and getting rid of standing water around your house.
“Getting rid of water now will reduce the West Nile virus risk down the road,” said George Balis, entomologist for Roselle-based Clarke Mosquito Control.
The company is in the process of larviciding catch basins, which kills mosquitoes while they are in the aquatic development stage, Balis said.
“One of the things we are doing now is using bicycles to treat catch basins,” Balis said. “It’s been more efficient than using trucks. We can treat more catch basins.”
Just like applying suntan lotion in the summer, Balis said people need to take the same precautions to prevent getting West Nile virus.
“You still have some people who will take their chances,” Balis said.
