A group of mosquitoes testing positive for West Nile were collected July 13 near Lakewood Drive and Summer Lakes Drive in Oakley, the same location where mosquitoes collected July 7 also tested positive, district spokeswoman Deborah Bass said.
Dead birds carrying the virus were found near Bordeaux Court and Tuscany Way in Danville, at St. George Drive and Port Chicago Highway in Concord, and at Via El Dorado Lane and Howe Road in Martinez, Bass said.
"This hot weather coupled with standing water is the perfect environment for mosquitoes and increases the risk for contracting West Nile virus through their bites," Bass said.
The continuing risk prompted health officials to remind county residents to use insect repellents containing DEET or oil of lemon eucalyptus, and to drain or report any standing water that could support mosquito breeding habitats, such as neglected swimming pools.
Residents who would like more information on eradicating potential water sources in yards, vaccinating pets against West Nile, mosquito fogging or receiving free mosquitofish for ornamental ponds should visit the district's Web site, http://www.ccmvcd.dst.ca.us.
Anyone wishing to report standing water or other mosquito problems should contact the district at (925) 771-6195 or visit their office at 155 Mason Circle in Concord between 8:00 a.m. and 4:30 p.m.