A case of measles has been reported in New Haven County, according to the state Department of Health.
Health officials said an adult resident of New Haven County came down with the measles and the rash starting on April 24.
The resident reportedly attended a Monday morning playgroup at the Blackstone Library at 758 Main Street in Branford on Monday, April 21.
Because the virus is highly contagious, everyone who was at the library between 10:30 a.m. and 1:30 p.m. Monday is asked to check with their doctors to make sure they've been immunized and watch for symptoms of the disease.
"I'm concerned. We have two children of our own," said Jim Lyons, who frequently brings his daughters to the library. "You assume you're safe, especially when you got a public library."
The Connecticut Department of Public Health is working with local health departments and health care providers to identify people who could have come in contact with the infected person, according to the state.
It's not clear how many people may have been exposed.
Symptoms of the illness include fever, a runny nose, cough and a rash all over the body. More information is posted on the Centers for Disease Control Web site.
Cases are infectious from four days before a rash begins through four days after.
The average incubation period for measles, from coming in contact with someone who has measles to a rash starting, is 14 days but can range from 7 to 21 days, according to health officials.
In February, two confirmed measles cases occurred in Fairfield County. One was an adult and the other an infant.
State health officials also said cases have been reported recently from states bordering Connecticut.
More information is posted on the state Department of Health Web site.