The sexually transmitted infection (STI), syphilis, has seen a rise in many areas of the globe, including the United States.

Japan Image/CIA

Japan, who reported a mere 621 syphilis cases just five years ago, it reporting a surge in cases in 2015.

According to data from the National Institute of Infectious Diseases, 2,272 syphilis cases have been reported from Jan. 1 to Nov.22. 1,670 cases were reported for all of 2014.

Tokyo led all cities with 910 cases to date, followed by 261 in Osaka and 135 in Kanagawa.

“We’re in the midst of a worldwide pandemic,” says Dr Yasuhiko Onue, an authority on sexually transmitted diseases. “Among the carriers I believe are also women from Asian countries visiting Japan,” Japan Today reports.

“It’s spreading because more people are engaging in sex without taking precautions”, says Tokyo Medical and Dental University professor emeritus, Koichiro Fujita. “Young females lacking knowledge of the ways of the world are overly trusting, and are persuaded by males to have sex with them without use of a condom.”

Syphilis, “baidoku” in Japanese, is a sexually transmitted infection that is spread by direct, skin to skin contact during unprotected sex. Pregnant women who are infected can transmit it to their unborn babies.