The Disneyland measles outbreak, which was first reported in individuals who visited two adjacent Disney theme parks located in Orange County, California in mid-December, has affected scores, according to a recent CDC Morbidity and Mortality Weekly Report (MMWR).
As of February 11, a total of 125 measles cases with rash occurring during December 28, 2014–February 8, 2015, had been confirmed in U.S. residents connected with this outbreak. Of these, 110 patients were California residents. Thirty-nine (35%) of the California patients visited one or both of the two Disney theme parks during December 17–20, where they are thought to have been exposed to measles, 37 have an unknown exposure source (34%), and 34 (31%) are secondary cases. Among the 34 secondary cases, 26 were household or close contacts, and eight were exposed in a community setting. Five (5%) of the California patients reported being in one or both of the two Disney theme parks during their exposure period outside of December 17–20, but their source of infection is unknown.
In addition, 15 cases linked to the two Disney theme parks have been reported in seven other states: Arizona (seven), Colorado (one), Nebraska (one), Oregon (one), Utah (three), and Washington (two), as well as linked cases reported in two neighboring countries, Mexico (one) and Canada (10).
The source of the initial Disney theme park exposure has not been identified. Specimens from 30 California patients were genotyped; all were measles genotype B3, which has caused a large outbreak recently in the Philippines, but has also been detected in at least 14 countries and at least six U.S. states in the last 6 months.
Public Health Canada reports that 5 of the Quebec cases were genotyped and were also genotype B3.
The Philippines recorded 57,564 suspected cases of measles, including 21,403 confirmed cases and 110 deaths from January 1 through December 20, 2014.
Of the 110 California patients, 93 percent were either unvaccinated, undervaccinated or had an unknown vaccination status.