(AP) -- Health officials say a high school is at the center of a tuberculosis outbreak in Sacramento County.
The Sacramento Bee reported Tuesday that four more students at Grant Union High School have contracted active TB. A student at the school tested positive for the disease earlier this year.
Beyond the Grant cases, four relatives and friends of the student who initially tested positive have also contracted active TB - bringing the total to nine known cases.
Sacramento County Public Health Officer Olivia Kasirye says three related tuberculosis cases is considered an outbreak.
Symptoms of active TB include a persistent cough and fever. Only active TB is contagious. It is spread through the air.