The hospital notified the state Department of Health of the exposure, as well as patients, family members and hospital staff who were in the emergency department when they could have been exposed. They will be given follow-up instructions, according to Kaleida's statement.

The individual with measles visited a county health clinic twice last week before being diagnosed at the hospital. Burstein said the individual went in for tests unrelated to the measles and did not have a rash at that time.

Measles is a highly contagious viral infection of the respiratory system. Those with measles develop a rash about two weeks after exposure, with the rash spreading downward across the body, starting with the head. Prior to developing a rash, those with measles typically develop a fever, eye inflammation, a cough, runny nose and sore throat.

The virus is transmitted to others when an infected person breathes, coughs or sneezes near others who do not have immunity or have not been vaccinated, according to the U.S. Centers for Disease Control and Prevention. It can infect others for up to two hours after an infected person has left an area. About 90 percent of vulnerable people who are exposed to someone with the measles become infected.