The California Department of Health Care Services (DHCS) has now identified 39 people in four states who have contracted measles, 35 of them California residents. Utah recorded two cases, while Colorado and Washington each had one case.

Most fell ill after visiting Disneyland or Disney California Adventure in December, while some were secondarily exposed to people who had traveled to the theme parks. DHCS said incubation period for people exposed at Disney parks ended last week, and health officials are on the lookout for secondary infections. According to the department, the original exposure took place between December 15 and 20, 2014.

Measles had been eliminated in the United States since 2000. However, large measles outbreaks have occurred in Western Europe, Pakistan, Vietnam and the Philippines in recent years. Travelers to areas where measles is endemic can bring measles back to the U.S., resulting in limited domestic transmission of measles. Disney and other theme parks in California are international attractions and visitors come from many parts of the world. 

Physicians are advised to consider measles in patients of any age who have a fever AND a rash regardless of their travel history. Fever can spike as high as 105°F. Measles rashes are red, blotchy and maculopapular and typically start on the hairline and face and then spread downwards to the rest of the body.

Physicians should obtain a thorough history on such patients, including whether the patient had traveled outside North or South America or had contact with international travelers (including transit through an international airport or a visit to an international tourist attraction in the United States) in the prior three weeks. Physicians should also be aware that undetected community transmission cannot be ruled out. Physicians should also ask about prior immunization for measles.

If you suspect your patient may have measles, isolate the patient immediately and alert your local health department as soon as possible. The risk of measles transmission to others can be reduced if control measures are implemented immediately.

Post-exposure prophylaxis can be administered to individuals who have come into contact with an infected patient within 72 hours of exposure (MMR vaccine) or up to six days after exposure (immune globulin - intramuscular). Please consult with your local health department regarding appropriate administration.

Click here for more information on diagnosis, isolation, reporting and prophylaxis of patients with measles.