INDIANAPOLIS -- Marion County health officials said they have confirmed the first pool of mosquitoes to test positive for West Nile virus.

The mosquitoes were found in the 1800 block of Caribbean Drive in Warren Township, said Marion County Health Department spokesman John Althardt.

Related: CDC: West Nile Virus Illness Continue To Decline | Tire Collection Aimed At Thwarting Mosquito Boom

"This tells us mosquitoes carrying the virus are active," said Chuck Dulla, mosquito control administrator. "We also know mosquitoes with West Nile virus are likely in most areas of the county. This is just the first site where we have confirmation."

There have not been any human cases of West Nile virus so far this year.

Health officials urged residents to walk around where they live and work and look for any containers capable of holding water, including clogged gutters, unused tires and poorly working septic systems.

The containers should be cleaned, covered or put indoors, officials said.

Anyone with questions concerning mosquitoes is asked to call the Marion County Health Department at 317-221-7440.