Hong Kong’s Department of Health is investigating an outbreak of measles that has infected three workers at the city’s airport.

The trio, employees at the Hong Kong International Airport, each developed a rash last week, according to a government statement late Friday. Another two cases were announced Saturday, one involving a man working for an airline and the other, a 11-month-old girl.

The man traveled to countries including Japan, Thailand, Indonesia and the Philippines during the incubation and communicable periods, according to a separate government statement.

He was a pilot with Cathay Pacific Airways Ltd., Radio Television Hong Kong reported, citing the government. Cathay Pacific and the Hong Kong government’s information department couldn’t immediately be reached outside of office hours to confirm a pilot was infected.

The Philippines is in the midst of a measles epidemic. More than 21,000 cases have been recorded this year and 315 people have died, its government said.

A health talk was conducted at the Hong Kong airport to deliver measles-related health advice to workers, a government spokesman said Friday. Measles mop-up vaccinations were given to close work contacts of the three patients to prevent the possible spread of infection, he said, referring to the infected airport employees.

At the beginning of March, a man developed full-blown symptoms of measles after boarding on a Cathay Pacific flight from Hong Kong to Tokyo. He was a flight attendant at the airline, the South China Morning Post reported.