ATLANTA – Two infected airline passengers may have helped spread Iowa’s mumps epidemic to six other Midwestern states, health officials said Wednesday, the latest example of how quickly disease can spread through air travel.

“These people may have exposed other people on those planes or in these airports,” said Kevin Teale, a spokesman for the Iowa Department of Public Health.

The mumps epidemic is the nation’s first in 20 years. Health officials say 515 suspected cases have been reported in Iowa, and the disease also has been seen in six neighboring states, according to the U.S. Centers for Disease Control and Prevention.

As of Monday, Nebraska has 43 reported cases; Kansas, 33; Illinois, four; Missouri, four; Wisconsin, four; and Minnesota, one.

The Iowa health department identified two people who were potentially infectious when they were traveling in late March and early April.

Officials in other states have not yet linked any cases to the air travelers. But because the illness’s incubation is two to three weeks, cases may not begin appearing until about now, Teale said.

This week the CDC put out an advisory about the passengers to state health departments. “Infectious diseases can travel easily on planes and other modes of transportation,” said Dr. Jane Seward, acting deputy director of the CDC’s viral diseases division.

The first traveler is Terry Poe Buschkamp, executive director of a Waterloo downtown development organization who in late March was in a delegation that traveled to Washington, D.C. She thought she caught it in the Dominican Republic.

The second person was a young man returning from vacation in Arizona on April 1, Teale said.

He flew American Airlines, from Tucson to Dallas, then to Fayetteville, Ark., to St. Louis and finally to Cedar Rapids.

No deaths have been reported.