Measles Outbreak in an Unvaccinated Family and a Possibly Associated International Traveler — Orange County, Florida, December 2012–January 2013

The Florida Department of Health in Orange County (DOH-Orange) was notified by a child care facility on January 11, 2013, that a parent had reported that an attendee and three siblings were ill with measles. All four siblings were unvaccinated for measles and had no travel history outside of Orange County during the periods when they likely had been exposed. A fifth, possibly associated case was later reported in a Brazilian citizen who had become ill while vacationing in Florida. The outbreak investigation that was conducted at multiple community settings in Orange County, including at an Orlando-area theme park, identified no additional cases. The genotype sequence was identical for cases 2-5, and visits to the same theme park suggested an unknown, common exposure and link between the cases. Sources of measles exposure can be difficult to identify for every measles case. Measles should be considered in the differential diagnosis of febrile rash illness, especially in unvaccinated persons. Reporting a confirmed or suspected case immediately to public health authorities is critical to limit the spread of measles.