The student and staff at Indio High School are all being tested for TB by the Riverside County Department of Public Health and state officials after 45 students tested positive for possible exposure, CNN reported.
"The entire school is being tested out of an abundance of caution," said Riverside County Public Health Officer Dr. Cameron Kaiser.
The county health department expanded the testing to the entire school "after results of an initial screening were higher than expected," spokesman Jose Arballo Jr. said in a statement. About 131 students were screened Monday.
"Someone who is exposed does not necessarily have active tuberculosis, a condition that must be confirmed with more tests," Arballo said. "On Thursday, follow up X-rays identified five students who require further examination."
Officials said there is one active case of tuberculosis and that they do not fear an outbreak.