While April 13 will go down in history as the day an F2 tornado ravaged Iowa City, UI sophomore Kara Molitor will remember the date for another reason. That morning, she learned she had the mumps.

Living in the dorms with a recently infected roommate, Kara figured the odds were good she'd catch it, too. She retreated to solitary confinement, missing more than a week of class, five shifts at work, and an Easter celebration with her family.

"All I wanted to do was sleep or just sit around," recalls Kara, a journalism and cinema major.

This past winter and spring, eastern Iowa emerged as the epicenter of the largest U.S. outbreak of mumps in almost 20 years. Typically, state health officials confirm five cases of mumps annually. But by early May, Iowa approached 1,300, with reports of mumps in several neighboring states. Mostly affecting students in university settings, the epidemic offered no hint of slowing down.

"It seems to have started in college students—most of whom talk with, kiss, and otherwise get up close and personal with other college students," says Mary Gilchrist, 67BA, director of the UI's Hygienic Lab, where staff hustled seven days a week to keep up with the 250-plus blood samples arriving daily for mumps testing.

Iowa's last major outbreak was in 1987, when 476 people were stricken. A usually mild viral infection of the salivary glands, mumps causes fever, headache, muscle aches, and swelling of the glands near the jaw. Rare, serious complications include meningitis and deafness.

One of the most puzzling aspects of the epidemic concerned its rampant spread among a vaccinated population. A mumps vaccine was first introduced in 1967. Ten years later, Iowa legislators mandated one dose of the combined measles, mumps, rubella (MMR) shot for school entrance and in 1991 began requiring two doses. Although a majority of college students have received two doses, says UI Student Health director Mary Khowassah, 64BS, 68MD, five to ten percent of them failed to develop immunity and remain susceptible to mumps.

In an attempt to halt the spread among the most susceptible group, the U.S. Centers for Disease Control shipped 25,000 doses of MMR vaccine to Iowa so that health officials on college campuses could establish mass immunization clinics for people 18 to 22 years old.

Experts don't know exactly why mumps came to Iowa. Even as the epidemic gained steam, Gilchrist remained hopeful that Mother Nature would lend a helping hand. "Spring was the traditional time for big mumps outbreaks in the pre-vaccine era," she says, "so the whole thing could fade as the redbuds drop their blossoms, the daffodils droop, and the peonies flop over in the late May rain."