As of July 1, mosquitoes in Clark and Elkhart counties have tested positive for the virus.
Clayton says South Dakota historically has a disproportionately high number of West Nile virus case compared with other states.
The state Department of Health has confirmed a human case of West Nile Virus (WNV) in a Hunterdon County man in his 70s.
Other preventive measures include avoiding being outdoors from dusk to dawn, when mosquitoes are most active, covering exposed skin and using an Environmental Protection Agency-registered insect repellent.
Symptoms include headaches, body aches and joint pain.
Most people infected with West Nile virus experience no symptoms.
West Nile virus can cause West Nile fever, which can develop into a more severe form of the disease that affects the nervous system. It's the most common disease transmitted from mosquitoes to humans in the United States, the CDC says.
Everyone is encouraged to walk around their home or property and look for areas of standing water where mosquitoes are most likely to breed.
Public health officials in New Jersey are bracing for what looks to be a summer of increased West Nile virus. "It only takes one chunk from an infected mosquito to trigger a severe sickness, so Hoosiers in each county needs to be taking precautions".
Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets, and barrels. Individuals who think they might have West Nile virus should see their healthcare provider.