Mumps epidemiology and demographics

Overview
In 2006, the United States experienced a multi-state outbreak involving 6584 reported cases of mumps. This resurgence predominantly affected midwestern college students with the highest attack rates occurring among those living in dormitories. In the following two years, the number of reported cases returned to usual levels, and outbreaks involved fewer than 20 cases.

However, beginning in July 2009, the largest U.S. mumps outbreak since 2006 has occurred. The index case was an 11-year-old boy who had returned on June 17 from the United Kingdom where an ongoing mumps outbreak involves more than 4000 cases. Because of the potential for more extensive disease transmission, efforts should be made to heighten surveillance for mumps and assure that children and adults are appropriately vaccinated against this disease.

Epidemiology and demographics
Paramyxovirus that is responsible to cause mumps is present throughout the world. According to WHO reports, approximately only 57% of the countries use mumps vaccine. Thereby, in many countries, mumps still remains endemic.

I. Canada: April 2007
Dalhousie University was struck with an outbreak of the mumps confirmed in many students and suspected cases in dozens of others. The main causes of the large outbreak include students being unaware of being infected, and other students who knowingly ignored quarantine restrictions. The outbreak began after St. Patrick's Day, and has spread beyond the university community, with confirmed cases reaching 350 cases of mumps since February, including about 24 new cases that have surfaced during the week ending June 9, 2007. The end of the university year in May meant that many students travelled to their homes across the country carrying the infection, leading to a large scale spread, the extent of which is still not clear, although the prevalence of the disease lay in people aged 17 to 24.

Roughly 50 personnel of the Halifax-based navy ship HMCS Glace Bay were sent home as a precaution. Reported outbreaks have begun in New Brunswick (Approximately 100 cases), Prince Edward Island (1 case), Ontario (3 cases confirmed, 5 suspected), West Coast of Newfoundland (2 cases), and Toronto (3 cases). On October 3rd 2007, a new case was reported at Nipissing University/Canadore College, in North Bay, Ontario.

II. United Kingdom: 2004 - 2007
In the United Kingdom over the last two years, a mumps outbreak has involved more than 70,000 patients. The cause of the outbreak was attributed to low immunity in those who were too old to have received MMR vaccine, but young enough to have not developed natural immunity through exposure. A catch-up programme of immunisation of under twenty five year olds, particularly in university towns such as Exeter was implemented.

On 12 November 2004, internal news from the University of Bath reported that twenty three students had presented to the University Medical Centre with Mumps. A Mumps Vaccination programme was announced to address the outbreak.

III. United States: 2005 - 2006
Although there may not be a direct link with the mumps outbreak in Ireland, United States CDC Director Dr. Julie Gerberding has been quoted stating that the genotype from the U.S. outbreak, in the early cases of this outbreak, was the same genotype of virus that was associated with the United Kingdom outbreak.

Entrez Gene contains a placeholder database record for a new Mumps gene; the record is dated 23 Feb 2006.

On 31 January 2007, 6404 cases of mumps in 2006 compared to 314 in 2005. As of today, YTD 15 deaths in the United States were reported.

1. Iowa (2005-2006)
In early 2006, for reasons still not fully understood, the state of Iowa experienced a large surge in the number of reported mumps infections. According to the New York Times, college students accounted for about a quarter of the 245 cases, while about half of the cases are people aged seventeen to twenty five. Doctors are attributing the rise in mumps case frequency to low vaccination rates in Iowa's youth, coupled with the close quarters in dormitories, classrooms and cafeterias.

According to Canadian media reports, there may be something novel about this mumps strain which indicates a standard MMR-series vaccination is not 95% effective, as was thought.

On 14 April 2006, Iowa has experienced more than 600 suspected cases since December. The mumps outbreak is the nation's largest in twenty years. On 18 April 2006, 815 cases have been reported in Iowa alone, representing a  caseload reporting increase of 200 in the last week. On 25 April 2006, there are over 1,120 confirmed, probable and suspected cases of mumps. Over 1000 of the cases are confirmed. By 2 May 2006, Iowa reported 1,487 cases. and confirmed 1,184, 253 probable, and 237 suspect cases, or 1674 total by 11 May 2006.

2. Georgia (2006)
28 April 2006: A confirmed case of mumps is reported in a college student at the Georgia Institute of Technology campus in downtown Atlanta.

3. Illinois (2006)
There have been three confirmed cases of the mumps at Southern Illinois University-Carbondale, Two cases at Loyola University Chicago, and has spread to three other neighboring counties in the Southern Illinois area. There has also been one confirmed case at Knox College, in Galesburg (Western Illinois). Wheaton College has also been affected by 93 cases since early September (as of Jan 9). By 9 May 2006, 279 total cases were reported. And by, September 28, 2006, The Illinois Department of Public Health has reported 636 cases of mumps in Illinois between January 1, 2006 and September 28, 2006. 

4. Indiana (2006)
21 April 2006: A case is reported in a college student at Indiana University.

5. Kansas (2006)
On 2 May 2006, 340 mumps cases were reported in Kansas, state health officials have asked the U.S. Centers for Disease Control and Prevention to help. By 10 May 2006, Kansas reported a total 546 cases.

6. Kentucky (2006)
4 May 2006: Two cases diagnosed by Doctor Roach in Paducah,KY, a border town to Southern Illinois.

7. Michigan (2006)
20 April 2006: A woman in Saginaw County was diagnosed with mumps, with another pending results. Cases in Oakland County and Delta County were previously confirmed, and results in neighboring Bay County came back negative.

04 May 2006: A case of the mumps is reported in Plymouth-Canton High School, Canton. The three high schools in Canton are requiring students to provide documentation of vaccination.

8. Minnesota (2006)
May 2006: The Minnesota Department of Health has confirmed eleven mumps cases in Minnesota in 2006. Four of the eleven cases may be linked to Iowa. Please continue to check back for updates. 

9. Missouri (2006)
10 May 2006: Missouri reports twenty one confirmed, eighty eight probable, for a total of 109 cases

10. Nebraska (2006)
10 May 2006: Nebraska reports sixty four confirmed, 193 probable, twenty two suspect, for a total of 279 cases in forty three counties. Officials say many people with mumps in Nebraska had connections to Iowa.

11. North Carolina (2006)
4 May 2006: An 8-year-old in Mecklenburg County is diagnosed with the mumps, the first case in the county since 2002. NOTE: This case may not be related to the current epidemic in the Midwest.

12. Oregon (2006)
18 May 2006: three cases in Lane County are confirmed, including a potential of four more at the University of Oregon alone. 

6 June 2006: twenty four confirmed and four presumptive cases in Lane County, two cases in Multnomah County, one each in Douglas, Hood River, and Linn Counties. 

13. South Dakota (2006)
12 May 2006: SD Department of Health reports thirty three confirmed cases, fifty three probable cases, and six suspect cases for a total of ninety two cases. 

14. Wisconsin (2006)
10 May 2006: 185 confirmed cases, at least one case in one out of three counties.

Resources
CDC: Mumps Outbreaks