摘要
Once thought to have been a thing of the past,measles has recently made a comeback.The trail of its return starts with an unvaccinated traveler visiting Shanghai,which is still widely affected by the disease.After leaving the city,the traveler continues on,but not alone.A number of new cases have been reported since January 2016.As a result,the Shanghai Disease Control and Prevention Center urges all parents to have their children vaccinated at their earliest convenience.
