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: A large outbreak of syphilis was reported in Dublin, Ireland, in 2001. The mean age of patients in 2001 was 35 years and 22.5% of patients were HIV-positive. The number of new cases decreased from 2003 on, however, new diagnoses have again increased.
All positive syphilis serology results from 2007-09 were identified. Patients were included if they had a newly positive syphilis serology or, in the case of patients with previously treated syphilis, had a four-fold rise in rapid plasma reagin titre. Four hundred and thirty-nine new diagnoses of syphilis were made. The mean age of patients at diagnosis was 35.7 years (range 17-73 years). Four hundred and twelve (93.8%) cases occurred in men. Three hundred and eighty-one (86.8%) cases occurred in men who have sex with men (MSM). The estimated crude incidence rate among MSM is 378.16 per 100,000 population.
Where known, 126/421 (28.7%) occurred in HIV-positive patients. Sixty-eight (15.5%) episodes of syphilis infection were diagnosed in patients who had had previously been diagnosed and treated for syphilis; 43/68 (63.2%) cases of re-infection occurred in HIV-positive patients. The rising number of syphilis diagnoses and high associated HIV co-infection rate is concerning and prevention efforts must continue to decrease the number of new syphilis cases. Treatment: The first choice for the treatment for syphilis is intramuscular benzathine penicillin G Doxycycline and tetracycline in alternative choice to those who are allergic to pencillins Resistance to macrolides, rifampin, and clindamycin is often present. Ceftriaxone, a third-generation cephalosporin antibiotic, may be as effective as penicillin-based treatment. It is recommended that a treated person avoid sex until the sores are healed. Major Research: Major Research on Syphilis is conducted by USPHS.