A swell in reported cases of mumps has Iowa health officials on the lookout. According to the Iowa Department of Public Health (IDPH), the state typically has an average of seven reported cases per year. As of March 16, 67 cases have been reported since the start of 2006 in 15 Iowa counties. That number has since grown.
The virus affects secreting cells at the back of the mouth and glands, and the response to infection produces swelling and pain mostly in the salivary ducts and glands found in the cheeks in front of the ear.
About 18 days after infection, symptoms such as earache, jaw tenderness, bodily discomfort, headache, low fever and anorexia begin. Many infected with the mumps virus show no symptoms or signs that would point to mumps infection. In 80 percent of the symptomatic cases, mumps clears up within 10 days and leaves only a hard immunity that lasts a lifetime. Approximately 20 percent of cases will be associated with some complications of nervous tissue or testicular tissue in males past puberty.
The virus is transmitted in saliva and can be transferred three to five days before symptoms even begin.
Mumps transfers between individuals via respiratory secretions like sneezing, coughing and even talking.
As for how the virus started spreading in Iowa, many scenarios are possible. An unvaccinated child visiting a country where vaccination is uncommon can bring back the virus and spread it to siblings, unvaccinated parents or classmates. Foreign college students are often implicated in campus outbreaks.
With the recent outbreak, the average age of the infected is 22, but seven cases involved children younger than 15 and 13 cases were reported for the over 40 age bracket.
Those who are 50 years old or younger should know their vaccination status. Children who attend Iowa schools should have proof of vaccination presented during enrollment, but there are estimates that 10 to 20 percent of the population has not received the recommended vaccinations. Those who do not remember being vaccinated may wish to discuss this with their health care provider.
The MMR vaccine has been available for nearly 40 years and remains at least 95 percent effective in preventing mumps. There are sub-strains of the mumps virus but this vaccine has been demonstrated to prevent each of the sub-strains. It is unlikely that those who have been vaccinated will be susceptible to this outbreak.
The CDC has determined that the strain spreading in Iowa is similar to the 2004-05 mumps outbreak in the United Kingdom and is covered by the MMR vaccine. In addition, the IDPH has formed a mumps sentinel surveillance network to detect cases quicker and ensure appropriate labs and paperwork are completed.