FAILURE OF PENICILLIN TREATMENT OF YAWS ON KARKAR-ISLAND, PAPUA-NEW-GUINEA

The endemic treponematosis yaws remains a significant cause of morbidi ty in many tropical countries, despite mass treatment campaigns to era dicate it. An outbreak of yaws in Marup village on Karkar Island, Papu a New Guinea in 1988 provided an opportunity to monitor the outcome of treatment with penicillin over an extended period. Thirty-nine childr en with clinical yaws (6% of 632 examined) were monitored clinically a nd serologically, for nearly two years after mass treatment of all vil lagers with the World Health Organization recommended dosages of benza thine penicillin. Lesions resolved within one month of treatment in al l but four (10%) children, three of whom were initially successfully r etreated. Before treatment, the Venereal Disease Research Laboratory ( VDRL) test result was reactive in 67% of the children and treponema-sp ecific IgM antibody test results were reactive in 41%. Within six mont hs of treatment, of those reactive, the VDRL titer decreased significa ntly in 25 (96%) of 26 and IgM antibody test results became negative i n 13 (81%) of 16 children. However, by the end of follow-up, 11 (28%) of the 39 children had developed clinical and/or serologic evidence of relapse. In these children, response to further treatment was slow an d, in three, evidence of active infection persisted or recurred, despi te repeated courses. Exogenous reinfection was unlikely in this isolat ed community, in which the occurrence of yaws was closely monitored af ter universal treatment. Treatment failure was most likely to have bee n due to reduced susceptibility to penicillin of Treponema pallidum su bsp. pertenue.