Investigations on reactivity of sera in endemic syphilis from Bosnia 20 years after treatment.

Sera from 225 patients who 20 years earlier had been infected with endemic syphilis and adequately treated with penicillin (PAM 4.8-6 megaunits) at various stages of the disease, were investigated for serological reactivity by the fluorescent treponemal antibody absorption (FTA-ABS), treponemal haemagglutination, and Venereal Diseases Research Laboratory tests. Specific antibodies were found in a large percentage of cases and their presence may be assumed to depend on persisting specific antigen which stimulates their synthesis.