SAN DIEGO -- Another 10 dead birds discovered around San Diego County have tested positive for West Nile virus, bringing the total number to 29 this year, county health officials reported Tuesday.

The latest finds were made in Vista, Carlsbad, Encinitas, Del Mar, Carmel Valley, Rancho Penasquitos, College Area, La Mesa and El Cajon, according to the San Diego County Department of Environmental Health.

"We have never seen this many positive birds so early in the season," said Gary Erbeck, director of the DEH.

"Last year, we found mosquito breeding areas in the backyards of all 15 local West Nile victims," Erbeck said. "It is imperative that residents protect themselves and check their own back yards for mosquito breeding sites every week."

Dead birds can be reported, and more information on West Nile virus obtained, on the county's Web site at www.SDFightTheBite.com, or by calling 888-551-INFO (4636).