Jacksonville, Florida - Officials from the Centers for Disease Control and Prevention are working with the Florida Department of Health to investigate the first Zika case that appears to have no connection to travel or sexual contact transmission.

Mayo Clinic internal medicine specialist Dr. Vandana Bhide from Mayo Clinic's campus in Jacksonville, Florida, says the challenge is determining if there is now an infected population of mosquitoes in the U.S.

“We know which mosquitoes carry the Zika virus, and they are very common and like being around people,” says Dr. Bhide. “The concern is that we don’t yet know if there is an infected mosquito population here in the U.S. or if there is some other person-to-person spread.”

"Identifying a population of mosquitoes that are infected with the Zika virus is not a simple process, despite the tracking and monitoring of the insects," says Dr. Bhide. “Now is the time when we need to think about this,” she adds, noting that the best defense against infection is to avoid being bitten.

To avoid mosquito bites, you should:

• Control environmental factors, such as standing water.
• Stay indoors more.
• Use insect repellant or protection such as mosquito nets.

According to local Florida news reports, health officials say they are investigating a second possible case of Zika spread locally.