DALLAS -- Dallas County Judge Clay Jenkins declared a public health emergency Thursday night, saying the spread of the West Nile virus has become epidemic.
Dallas County health officials have reported 162 West Nile virus cases and nine deaths this year.
Mosquitoes pick up the virus from birds they bite and spread it to people.
The nation's top health officials say more serious illnesses from West Nile virus have been reported this year than any since 2004.
About 80 percent have been in Dallas, Tarrant, Collin and Denton counties, the state health department says.
On Tuesday, Dallas County commissioners supported a recommendation from county health officials to continue the targeted spraying of insecticide from the ground, mostly in north Dallas, declining a proposal for aerial spraying. The Dallas County Medical Society's community emergency response committee voted 13-0 Sunday night to recommend the first aerial spraying in the city since 1966.
Tarrant County health officials have recorded 131 cases and one death.
Denton County reported one death and 66 cases. Collin County reported 16 cases and no deaths.