Health authorities in the US state of Arizona are on high alert after a thousand people may have been exposed to measles.

Arizona's Department of Health has recommended that any unvaccinated child or adult who had been in contact with infected people to spend 21 days in isolation at home to curb the risk of spreading the virus.

Director Will Humble says it's a critical point in the outbreak, which has centred around the Disneyland theme park in Anaheim outside Los Angeles.

There have so far been 84 confirmed cases in 14 states - 67 of which are linked to the Disney outbreak.