Pupils have been asked to self-isolate after a classmate tested positive for coronavirus at the Community School of Auchterarder.
All close contacts of the youngster have been advised to stay home until October 2.
Heath chiefs said there was no evidence of transmission within the school.
Parents were told of the single case in an email from the Perth and Kinross Council-run school on Saturday night.
NHS Tayside consultant in public health medicine Dr Emma Fletcher said: “I would like to reassure parents that if you have not been contacted individually this means that your child has not been identified as a contact in the school, and they can continue to attend school and undertake other activities as normal. All appropriate precautions are in place and the schools remain open.”
Perth and Kinross Council’s Lifelong Learning Committee Convener Councillor Caroline Shiers added: “I hope the pupil makes a speedy recovery. Every time there is a confirmed case of Coronavirus in schools it is unsettling for everyone in the school community.
“A number of pupils at the Community School of Auchterarder will have to self-isolate because of this case but this disruption is necessary to prevent further spread of the virus.
“Our dedicated teachers will continue to provide excellent learning online while pupils are isolated.”