Chou Jih-haw (周志浩), deputy director of the DOH's Center for Disease Control, said that although no one has been infected after coming into contact with the baby boy, the DOH will not let down its guard until mid-March.

The 15-month-old baby boy living in central Taiwan caught the measles when he was hospitalized for diarrhea while traveling with his mother in Hunan, China, Chou said.

He returned to Taiwan on Feb. 5, and developed a bad fever the following day. He was diagnosed as contracting the measles and stayed in hospital for six days.

Chou noted that since December, there have been four imported measles cases, adding that recently a baby girl was found to have contracted measles after returning to Taiwan, and a baby boy in the same ward was infected, while five others are suspected of being infected.

Taipei and Taoyuan counties are now tracing those who have had contact with the baby girl and vaccinated those children who had yet to receive measles shots.

Chou noted that the outbreak of measles in China over the past three years have become more serious, with the number rising from 100,000 to 130,000 over that time. Some 4,600 people have been infected with the disease in China since January.

"Those who travel to China with their young children should be on high alert," Chou warned.