Mumps Outbreak: An Introduction
The state of Iowa has been experiencing a large outbreak of
mumps that began in December 2005. As of April 12, 2006, 605 suspect, probable, and confirmed cases of mumps have been reported to the Iowa Department of Public Health (IDPH). The majority of these cases are occurring in people 18 to 25 years of age, many of whom were vaccinated.
Additional cases of mumps, possibly linked to the Iowa mumps outbreak, are also under investigation in eight neighboring states, including:
- Illinois
- Indiana
- Kansas
- Michigan
- Minnesota
- Missouri
- Nebraska
- Wisconsin.
Where Did the Outbreak of Mumps Start?
The source of the current mumps outbreak in the United States is unknown. However, the mumps strain has been identified as genotype G, the same genotype circulating in the United Kingdom. The outbreak in the United Kingdom that lasted from 2004 to 2005 involved more than 70,000 cases. Most cases in the United Kingdom occurred among unvaccinated young adults. The G genotype is not an unusual or rare genotype and, like the rest of known genotypes of mumps, it has been circulating globally for decades, if not longer.
Current information indicates that the outbreak of mumps may have begun on a college campus in eastern Iowa. Colleges that have group living, dining, studying, and sports are areas that make
mumps transmission more likely and that increase the chance of an outbreak. Once started, outbreaks can spread to the community, causing the illness in people who do not attend college.
