The Philadelphia Quarantine Station, operated by the U.S. Centers for Disease Control and Prevention, has requested manifests from two flights on Aug. 25 - from the Dominican Republic to Miami and then from Miami to Philadelphia - on which the student was a passenger, said CDC spokeswoman Christine Pearson.
The CDC will then work with the Pennsylvania Department of Health to track down passengers who sat in the same row and in two rows ahead and behind, Pearson said, as well as any "lap babies" who are too young to have developed immunity after vaccination.
She said casual exposure in the airport is not a concern because most Americans have been vaccinated or gained immunity after infection years ago.
The two recent cases are the only measles infections that have been reported in Montgomery County since at least 2006, Morton said.
The first case involved a 47-year-old woman who had recently traveled to Malawi. She developed symptoms and became infectious after returning home, Morton said, and has recovered.
Measles, a respiratory disease that spreads primarily through breathing, coughing, or sneezing, is so contagious that almost every child who does not have immunity and gets exposed to the virus will become infected, according to the CDC. Common symptoms include fever, runny nose, cough, and a rash all over the body, but it can also cause ear infections and pneumonia. One or two of every 1,000 cases in children is fatal.
Contact staff writer Don Sapatkin at 215-854-2617 or dsapatkin@phillynews.com.