Maricopa County is targeting mosquitoes that could be carrying the West Nile virus.
Weather permitting, the county plans to conduct mosquito fogging Thursday in a handful of places.
The spraying in Chandler, Gilbert, Mesa, Phoenix and Queen Creek is expected to last about five hours. All of the communities had mosquitoes that have tested positive for carrying West Nile or have a large concentration of mosquitoes.
Maricopa County confirmed its first death from West Nile virus on Tuesday. The victim was an older man with pre-existing health problems.
The virus can cause serious illness in humans and horses. Only 20 percent of those infected will develop flu-like symptoms, but some people, especially the elderly, may experience heightened symptoms including death, according to health officials.
The following areas are scheduled to be fogged between midnight and 5 a.m. Friday:
State health data shows that Arizona had 67 cases of West Nile last year, four of which were fatal. There have been more than 1,000 case reported cases since the virus was discovered in Arizona in 2003.
Copyright 2012 Associated Press. All rights reserved. CBS 5 (Meredith Corporation) contributed to this report.