Health officials tracking a measles outbreak said on Wednesday there are now a total of five confirmed and suspected cases in Boston.
The tally includes a second confirmed case of measles in a woman living in the same building as a woman diagnosed last month, city health officials said. Three more suspected cases are being monitored, with final lab results expected sometime next week.
The initial measles case in Boston was a young woman employed at the French Consulate. Health officials believe she contracted measles overseas.
Elsewhere in the country, in an unrelated case, health officials are on the lookout for measles cases that might be tied to an infected plane passenger. The New Mexico woman took a series of flights last week, passing through four major airports in Virginia, Maryland, Colorado and New Mexico and spent time in Washington, DC.
In Boston, one of the suspected cases is a University of Massachusetts-Boston professor in his 40's, whose symptoms were reported earlier in the week. The school has notified about 45 students and five faculty who may have been exposed to measles.
As part of their effort to contain the spread of the illness, Boston health officials have been offering free vaccination clinics.
People are considered immune to measles if they have had two doses of the vaccine or were born in the United States before 1957.
Symptoms of measles look and feel like a cold initially, but later a rash develops on the face and spreads to the rest of the body. People are contagious four days before and four days after the tell-tale rash appears.
Measles is a leading cause of death among young children in the developing world, but is seldom seen in the United States where vaccination is required of all school children.
Because the rate of immunization in the United States is so high and colleges are diligent about ensuring entering freshman are appropriately immunized, epidemics in the United States do not take hold easily, said Dr. Mark Pasternack, chief of the pediatric infectious disease unit at Massachusetts General Hospital.
There were 61 reported cases of measles in the United States in 2010 and 12 cases reported this year through mid-February, according to Centers for Disease Control and Prevention data.
The most recent large outbreak of measles in the United States was in 2008, when more than 130 cases were reported in 15 states, according to the CDC.