The rapid rise of syphilis, including among young women, has prompted the health ministry to form a special research team to find ways of stopping the sexually transmitted disease.

According to hospital reports from across Japan, there were 4,259 syphilis cases from Jan. 1 to early December 2016, up 77 percent from the 2,412 cases logged in the same period in 2015, and up by more than seven-fold from a decade ago.

Most of the cases are believed to be caused by heterosexual intercourse, but cases of mother-to-child transmission, which is rare, are also on the rise.