The Japanese National Institute of Infectious Diseases reported for the second year in a row more than 5,000 syphilis cases in the country. With 88 cases reported the last week of September, health officials put the case tally at 5,081.

syphilis
Image/CDC

In all of 2017, Japan saw 5,534 syphilis cases, the first time that happened in more than 4 decades.

Nearly 1,300 of the cases have been reported in Tokyo, while Osaka reported more than 800 cases. The sexually transmitted infection is seen mostly among men in their 20s to 40s and women in their 20s.

“Many of the patients are women involved in sex-related work and men who are their customers,” said Yasuhiko Onoe, director of Private Care Clinic Tokyo in Shinjuku Ward, Tokyo, which provides treatment for sexually transmitted diseases as reported in The Japan News. “There are also cases in which a husband infected [with syphilis] transmits [the disease] to his wife,” the doctor added.

Syphilis is a sexually-transmitted disease (STD) that can cause long-term complications if not treated correctly. Symptoms of syphilis in adults include a painless sore that will go away without treatment followed by a non-itchy body rash. If left untreated syphilis can lead to damage through the body including neurological and cardiovascular complications. Syphilis also increases the risk of HIV infection and, for women, can cause problems during pregnancy and for the newborn.