Students from two Bay schools may have been exposed to measles after attending a sports tournament in Hamilton.
An Auckland student playing at the New Zealand Secondary Schools Girls Football tournament last week was later confirmed to have measles. The tournament was also attended by students from Katikati and Mount Maunganui Colleges.
Leigh Perry, the NZ Secondary School Sports national administrator, said the Waikato public officer of health notified her of the confirmed case. She immediately contacted the senior managers at the eight schools involved in the tournament.
"The problem was the teenager did not know they were infected until they returned home."
Perry said the eight schools involved included teams from Waikato and Wellington.
"The concern is measles lies dormant for 10 days and people may not know they have it until they start experiencing symptoms."
Perry said three weeks prior to the tournament, which ran from September 2 to 5, she notified the schools urging them to ensure all their students were vaccinated.
School Sports New Zealand also sent out the same message to schools in relation to all winter sports tournaments, she said.
Toi Te Ora medical officer of health Dr Phil Shoemack said so far there were 41 confirmed cases of measles in the Bay of Plenty and Lakes Districts this year.
Shoemack said Toi Te Ora was working with the two local schools to identify anyone at the tournament who had contact with Auckland student or may be at risk.
"Any of those who have not been vaccinated and may have potentially been exposed will be placed into quarantine."
Shoemack said any adults who attended the tournament would also need to check their vaccination status and potential exposure.
Mount Maunganui College principal Alistair Stainton said the college was working to notify any of those that may have been exposed and was communicating with the wider school community.
"As with all schools, we are following the advice of Toi Te Ora Public Health, Ministry of Health and Ministry of Education."
Katikati College's principal could not be contacted for comment.