An electron microscope image of the measles virus.
Centers for Disease Control and Prevention

DES MOINES — Patrons of two restaurants in the Des Moines area may have been exposed to measles in the past week and a half, according to the Iowa Department of Public Health.

A Missouri resident, whose measles infection has been confirmed, had breakfast April 13 at a Hardee's on Merle Hay Road in Des Moines and lunch April 16 at a Panera Bread on Southeast Delaware Avenue in Ankeny, Iowa.

"Since it is too late to prevent these exposed people from coming down with measles, they could become ill and start spreading the disease any day now," Dr. Patricia Quinlisk, the department's medical director, said in a news release. She advised that anyone in the Des Moines area who has not received two doses of measles vaccine get the vaccine or booster immediately.

"That way if they are exposed in the next month or so when they go about their normal activities, they will be protected," she said.

Two doses of the measles, mumps and rubella vaccine, generally given at age 12 to 15 months with a booster at 4 to 6 years old are 97% effective in preventing measles. One dose is 93% effective, the federal Centers for Disease Control and Prevention said.

► April 7: College student with measles had been vaccinated, health officials say
► April 5: Contagious student goes skiing, shopping before measles rash erupts
► March 16: Measles patient treated, isolated after Memphis arrival

People who contract measles, a respiratory disease with symptoms that include a red rash and fever, are contagious four days before the rash appears to four days after it appears, according to the CDC. Measles is so contagious that 9 in 10 people who get close to someone infected also will get the disease if they're not immune.

The measles virus is transmitted via the misty droplets that come when an infected person coughs, sneezes and even breathes. The virus can live up to two hours in the air and on surfaces in a room where an infected person has been.

Once a person becomes infected, no cure is available. Complications of the disease can include pneumonia and a swelling of the brain called encephalitis.

► March 14: Travelers who landed in Detroit, Newark, Memphis pop up with measles
► Feb. 27: NYC officials issue warning after Australian tourist leaves infectious trail

Someone who suspects that they've been exposed to the measles virus should call ahead before going to an urgent care facility or doctor's office so staff can make arrangements to reduce the potential risk to others who are sick. 

Kansas has had 18 confirmed cases of measles in several counties since March 8. Those cases have been traced back to a day care.

Missouri now has four confirmed cases of measles, all from the Kansas City area. 

► Oct. 27: Michigan mom jailed over vaccine refusal: Don't give my son more shots
► Sept. 10: One way for anti-vaxxers to skip shots for schoolkids: A doctor’s note

In 2015, the United States experienced a large, multi-state measles outbreak linked to Disneyland in California, and 2014 outbreaks included one with 383 cases largely among unvaccinated Amish communities in Ohio.

Iowa has not had a measles cases since 2011.

Follow Kim Norvell on Twitter: @KimNorvellDMR