New York College Student With Measles Boarded Amtrak Train at Penn Station

— -- A New York college student with measles boarded an Amtrak station from Penn Station earlier this week and may have exposed other passengers to the contagious virus.

The student at Bard College in Dutchess County took Amtrak train #283 from Penn Station to Albany, according to state health officials. He got off in Rhinecliff, N.Y.

He has been isolated during his recovery, said officials with the college.

"In order to prevent the spread of illness, DOH is advising individuals who may have been exposed and who have symptoms consistent with measles to call their health care providers or a local emergency room BEFORE going for care. This will help to prevent others at these facilities from being exposed to the illness," said a statement from the New York State Department of Health.

At Bard College, the Dutchess County Department of Health held a measles vaccination clinic for any students, faculty, or staff who have not been vaccinated against measles. New York has had three cases of measles this year, the department said, one in Dutchess County and two in New York City.

New York requires that all college students show proof of immunity to measles. At Bard College, medical forms show that a student's immunity to the disease must be documented, but they don't state whether exemptions are allowed.

The current nationwide outbreak of measles has spread to 14 states and includes 84 cases reported this month.

Measles is one of the most contagious viruses in existence and will infect an estimated 90 percent of people who not immune to the virus. The incubation period is on average 14 days, but an infected person can be contagious up to four days before they start to show symptoms.

ABC News' Dr. Richard Besser contributed to this story.