DALLAS (AP) Health officials say a dozen people have died in North Texas as a result of being infected with the West Nile virus.

Dallas County Health and Human Services on Monday announced the 12th death. Further details on the victim and when or where the death occurred were not immediately released.

The West Nile death toll has reached at least 20 in the Dallas-Fort Worth area. Denton County health officials say a Carrollton woman who was in her 80s died Friday from West Nile fever.

Mosquitoes spread the virus from birds to people.

Aerial spraying of insecticide was completed last week in parts of Dallas County. Ground spraying was scheduled to continue Monday night in parts of Dallas.