Disease pathophysiology: Syphilis is a Sexually Transmitted Disease (STD) caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis. Other human diseases caused by related Treponema pallidum include yaws (subspecies pertenue), pinta (subspecies carateum) and bejel (subspecies endemicum). Disease Statistics: Syphilis has been placed under the category IV notifiable infectious diseases under the National Epidemiological Surveillance of Infectious Diseases since April 1999.
The physician who has diagnosed a syphilis case must notify it to the nearby health center within 7 days. The disease is classified into four types depending on the stage; early symptomatic (primary and secondary syphilis), late symptomatic, asymptomatic and congenital syphilis. During April-December 1999, 735 cases, during January-December 2000, 769 cases (0.61 cases per 100,000 population), and during January-December 2001, 581 cases (0.46 cases per 100,000 population) were reported, totaling at 2,085 cases. Of these cases, 754 were early symptomatic (342 primary and 412 secondary), 131 late symptomatic, 1,177 asymptomatic, and 23 congenital syphilis cases. Male cases numbered at 1,385 and female ones at 700; male cases exceeded female ones in early and late symptomatic syphilis.
Cases reported in Osaka, Tokyo, Fukuoka, and Hyogo prefectures accounted for 47% of all cases; early symptomatic cases were outstanding also in Osaka and Tokyo prefectures. The ages of the cases were widely spread; there were many young adult cases of early symptomatic syphilis, with a peak at 25-29 years. Many asymptomatic cases may have been found by syphilis testing at examinations for other STIs, blood donation, health check-up for the pregnant women, examinations before surgical operation, etc. Of 5,774,269 instances of blood donation during January-December 2001, there were 11,309 antibody positives (about 0.2%) by the Tp particle agglutination test (Japanese Red Cross Society). There were particularly a large number of asymptomatic cases among the aged persons due to the finding in the tests at the time of entering the facilities for the aged. Major Research: Major Research on Syphilis is conducted by Syphilis Diagnostic Market.