Mumps Outbreak in the U.S. State of Iowa

The Public Health Agency of Canada is currently monitoring a large outbreak of mumps in the U.S. state of Iowa as well as several smaller outbreaks in neighbouring states.

Iowa : According to the Iowa Department of Public Health, between December 2005 and April 19, 2006 a total of 975 confirmed, probable, and suspect cases of mumps have been reported in what has become the largest mumps outbreak in the United States since 1988 .

At this time, 66 of 99 counties have reported mumps activity and cases have been confirmed in at least one county bordering each neighbouring state.

The majority of cases have occurred among persons 18 to 25 years of age. A significant proportion of cases have been reported in individuals who had been previously vaccinated with two doses of MMR vaccine. Investigations concerning this anomaly are ongoing.

The Centers for Disease Control and Prevention ( CDC) has confirmed the strain in this outbreak as genotype G. Genotype G is not uncommon and is similar to the strain responsible for the 2004-2005 mumps outbreak in the United Kingdom. The source of this outbreak has not yet been established.

Additional outbreaks of mumps, possibly linked to the outbreak in Iowa have been reported in the neighbouring states of Kansas, Nebraska, and Illinois. The states of Indiana, Michigan, Minnesota, Missouri, and Wisconsin are also reporting case activity but to a lesser extent.

Kansas : As of April 19, the Kansas Department of Health and Environment has received 147 reports of confirmed and probable mumps cases. Cases have been reported in 31 of 105 counties, the majority of which have occurred in Douglas County (84 cases). Investigation is under way to determine if there are links to outbreaks in other states.

Nebraska : As of April 16, Nebraska's Health and Human Services System has received 109 reports of suspected mumps cases, 32 of which have been laboratory confirmed. Cases have been confirmed in 18 of 93 counties.Officials indicate that many of the cases in Nebraska have connections with those in Iowa.

Illinois : As of April 14, the Illinois Department of Public Health has received 72 reports of mumps cases, 35 of which have been confirmed. Officials indicate that three of the cases in Illinois have connections with Iowa.

Since 2001, in the U.S., an average of 265 mumps cases (range: 231--293 cases) have been reported each year. In Iowa, an average of five cases has been reported annually since 1996.

Source: Iowa Department of Public Health, CDC, Kansas Department of Health and Environment, Nebraska's Health and Human Services System, Illinois Department of Public Health

Mumps is an acute viral disease with symptoms that include fever, swelling, and tenderness of one or more salivary glands under the jaw and in the cheeks. It is spread by direct contact with or inhalation of the secretions from an infected person's nose or mouth. A vaccine is available to protect against mumps.

Mumps occurs worldwide. People living in colder climates are especially susceptible between November and March. Where national vaccination programs have been implemented, the number of mumps cases has dramatically declined worldwide in all age groups and the risk of infection is greatest among older, unvaccinated groups.

For more information on Mumps, please visit the Travel Medicine Program's Disease Information Backgrounder on Mumps.

In Canada, between 1999 and 2001, 87 to 102 cases of mumps were reported annually. Outbreaks occurred in 1997, 1998, and 2002. The 1997 outbreak occurred among university students in British Columbia and the 1998 outbreak occurred in Quebec among school children from families who had recently emigrated from countries where mumps vaccine was not included in the routine childhood immunization program. In 2002, 205 cases were reported, 193 of which were related to a localized outbreak in Alberta, in a largely unimmunized population who declined vaccination for philosophical reasons.

Recommendations

Canadians travelling internationally should ensure that their routine childhood immunizations - including diphtheria, whooping cough (pertussis), tetanus, polio, measles, mumps and rubella - are up to date before travelling, regardless of their destination.

The National Advisory Committee on Immunization recommends vaccination of all children at 12 months of age with a combined vaccine against measles, mumps and rubella (MMR) followed by a booster dose at either 18 months of age or at 4 to 6 years of age.

As a reminder...

The Public Health Agency of Canada routinely recommends that Canadian international travellers consult their personal physician or a travel clinic four to six weeks prior to international travel, regardless of destination, for an individual risk assessment to determine their individual health risks and their need for vaccination, preventative medication, and personal protective measures.

The Public Health Agency of Canada recommends, as well, that travellers who become sick or feel unwell on their return to Canada should seek a medical assessment with their personal physician. Travellers should also inform their physician of any travels or accommodations made outside of Canada.

Additional information from the Public Health Agency of Canada:

• To view “Immunizations recommended for travel outside of Canada”, go to : www.phac-aspc.gc.ca/tmp-pmv/236_e.html

• To view the Canadian Immunization Guide by the National Advisory Committee on Immunization, go to: www.phac-aspc.gc.ca/publicat/cig-gci/index.html