An outbreak of the measles virus has hit the Waikato with 8 confirmed cases and a further three possible cases having been reported. 

Waikato District Health Board has been notified 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 out break 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 event held on April 16 in Hamilton where around 5000 gathered for the festival. 

The DHB said any secondary cases from the festival would be expected to be developing symptoms this week.

There have been no confirmed cases resulting from attendance at the event to date however attendees should be looking out for symptoms until April 30. 

Another person who tested positive for measles also attended Nga Taiatea Wharekura School while infectious prior to the school holidays.

The first symptoms of measles are fever, runny nose, sore runny eyes, a cough and later on, a rash.

Of the eight confirmed cases, all patients were treated in the Waikato Hospital Emergency Department. Three required hospitalisation and have been since discharged.

The measles virus is highly infectious and can be very serious. 

It is spread by tiny droplets in the air and is one of the few diseases that can spread so easily to those nearby.