Authorities are warning that mosquitoes infected with the West Nile Virus have been found in Louisville.
Approximately 80% of people infected experience no symptoms, but up to 20% can develop a mild illness, called West Nile fever.
The West Nile virus does not usually affect domestic animals, but can cause severe illness in horses and certain species of birds. This year, the Illinois Department of Public Health has reported four human cases with no deaths.
More than 250 "pools" of mosquitos have tested positive for the virus so far this season, Giordano explained.
The Warren County Health District provides tips on how to reduce your risk of being bitten by mosquitoes.
Cases of the virus appear to be picking up in Oklahoma, although no cases have been confirmed in LeFlore or neighboring counties.
West Nile Virus was originally identified in 1937 from the blood of a woman living in the West Nile district of Uganda.
To prevent mosquitoes from breeding in standing water - in ponds, bird baths, animal watering troughs, stock tanks, neglected swimming pools and rain barrels - use a product that contains BTI (Bacillus thuringiensis israelensis) such as Mosquito Dunks.
According to Toronto Public Health, 31 mosquito traps tested positive in the city since August 16. "They may not be in greater abundance, but definitely at this time is when we start to see the positive traps and unfortunately this is when we start to get into some of the human cases".
When a donut-shaped Mosquito Dunk is placed in standing water, mosquito larvae eat the BTI and quickly die. Those who do can show symptoms such as fever, headache, body ache, fatigue, nausea or rash.
Use a mosquito repellent with an EPA-registered ingredient such as DEET while you are outdoors. Make sure your doors and windows have tight fitting screens that keep mosquitoes out.