Tests done Wednesday at an elementary school in Lake Forest where students and staff have been afflicted with rashes were negative for live pests, a spokeswoman for Saddleback Valley Unified School District said.
The Orange County Mosquito and Vector Control District did a "follow-up assessment" Wednesday morning at Lake Forest Elementary School, said Tammy Blakely, assistant to the superintendent of the school district.
District officials are working with the Vector Control District, the Orange County Health Care Agency, the city of Lake Forest and Safety First Pest Control to "identify and address the issue" of the outbreak of rashes, Blakely said.
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"The entire campus was sprayed, both inside and outside classrooms, and all field areas this weekend with a general pesticide that is safe for use at schools," Blakely said.
The tests Wednesday morning "came back negative for any live pests," she said. "Out of an extreme abundance of caution, the entire campus will be sprayed again this weekend, both inside and outside classrooms, and all field areas to ensure that all concerns have been addressed.''
So far, about 30 students and 10 staff members have been afflicted with the rash, Blakely said. The outbreak was first reported on Sept. 15.
The source of the rashes is a serious whodunit, said Jared Dever of the Vector Control District.
"Dozens of traps have been laid for the past week and a half," he said. "What we're looking for is a wide variety of biting or stinging insects."
After an initial investigation of the campus, "we ruled out mosquitoes and other types of vectors," Dever said. "That led us to look for different types of biting or stinging insects."
It's unlikely bed bugs are the culprit because they're noticeable and usually strike when victims are asleep and immobile, Dever said.
An outbreak of this size was "infrequent," he said.