The girl, who is from Plymouth, was initially suspected to have tonsilitis and complained of ulcers in her throat, Plymouth Live reported.
She also suffered from convulsions, red, blotchy skin and fever, as well as “severe” pain in her legs and body aches, the report said.
Symptoms that are more commonly associated with the virus include a dry cough and other upper respiratory issues, such as trouble breathing.
The girl’s school warned others about her confirmed case in a letter home to parents, according to the report.
“Please monitor your children and yourselves carefully for symptoms, stay at home and stay safe,” the letter said.
There have been more than 450,000 people infected by the virus worldwide, with the majority of severe cases in older patients and people suffering from underlying health issues.
More than 8,000 people in the UK have tested positive, according to Johns Hopkins University data.