Dallas-area officials have launched an aerial assault on the mosquito population in the hope of ending a West Nile virus epidemic.

That epidemic has sickened at least 230 Dallas County residents and killed 10 of those.

The aerial spraying began at 10 p.m. Thursday, focusing on the county's northeast quadrant the first night.

It's the first time in more than 45 years that Dallas County launched aerial spraying against mosquitoes. The efforts have provoked a debate between health officials trying to quell disease risk and people concerned about insecticidal mist drifting down from above.

The hot, dry weather has created ideal conditions for mosquitoes, speeding up their life cycle and turning standing water stagnant.