A warning is being directed especially toward hikers, mountain bikers and others who spend time in wooded areas or high grassy areas.The Allegheny County Health Department and the Pennsylvania Department of Environmental Protection say the deer tick population is at its highest in a decade and 40 percent carry the bacteria that causes Lyme disease.VIDEO: Watch Sheldon Ingram's report"I developed Bell's palsy. I couldn't close my eye or this side of my mouth," says Stacey Gray, of Glenshaw. Bell's palsy is a neurological condition affecting muscles in the face and resulting in disfiguration, one of the worst stages of Lyme disease if a tick bite is not caught and treated in a timely manner."Over the last to five to eight years, we've seen a tremendous increase so Lyme disease is definitely here in Allegheny County," says Dr. Kristen Mertz, an epidemiologist with the county Health Department."Ticks are more widespread than they used to be, and 40 percent are infected with the bacteria," says Mertz.The public is advised to avoid high grassy areas if possible; wear long, light-colored clothing; use Deet and Permethrin repellants for skin and clothing; and check for ticks and take a shower when returning home from wooded areas and trails.