For the second time in less than a week, the Park Cities will undergo aerial spraying for mosquitoes, weather permitting, in an effort to stop the spread of West Nile virus throughout the area.

The spraying will begin for both Highland Park and University Park at 8:30 p.m. Monday, and because of which, the Holmes Aquatic Center will shut down for the evening at 7:30 p.m.

The second round of spraying will take place to kill new mosquitoes born since the last round. 

Crews with the Centers for Disease Control are in Dallas County to observe and learn from the spraying operation, WFAA-TV (Ch. 8) reported on its website. The county doesn't have any new data from the West Nile virus traps, but it's expecting additional information from trapped mosquitoes sometime in the next 24 hours.  

Dallas County Judge Clay Jenkins, who declared an emergency, told the station that preliminary results show the chemical is working.

"What we're seeing from the test so far is a decrease in the West Nile virus carrying activity mosquitoes in the traps," he said.

For more information about aerial spraying, click here or visit the City of University Park's website.