An outbreak of the measles virus has hit the Waikato with eight confirmed cases and a further three possible cases reported.
Waikato District Health Board (DHB) has been notified of 18 possible cases of measles. Eight cases were confirmed, three are under investigation and seven have been determined not to be measles.
The DHB has warned the outbreak could spread further due to several known incidents of infected people attending large events and schools while ill.
One person who tested positive for measles attended the regional Tainui Waka Kapa Haka festival, held on April 16 in Hamilton, where around 5000 gathered.
The DHB said any secondary cases from the festival would be expected to be developing symptoms this week.