The mosquito-transmitted West Nile virus is working its way through the Valley. Maricopa County has confirmed 35 cases, including two deaths, so far this year, an uptick from the same time a year ago.

Dr. Rebecca Sunenshine with the Maricopa County Public Health Department says this year’s count is probably an underestimate.

"We know that we’re only seeing the tip of the iceberg. A lot of people are getting infected and may not even know that they’re getting sick with West Nile, may not go to the doctor to get diagnosed, and some aren’t getting diagnosed properly," Sunenshine said.

Sunenshine says flu-like symptoms occur in 20 percent of the infected people. Officials recommend residents avoid the outdoors during dawn and dusk, wear long-sleeved shirts and pants, and use mosquito repellant with DEET.

They also should clear out stagnant water where mosquitoes breed from their property.