Yaws in West Sumatra, Indonesia: clinical manifestations, serological findings and characterisation of new Treponema isolates by DNA probes

Abstract

The results of a yaws survey on the island of Sumatra in Indonesia are presented. The prevalence of yaws in the investigated region was found to be very high, a minimum of 300 cases per 100,000 individuals, which indicates that yaws is far from being eradicated and that campaigns for treatment are necessary. Patients suffering from early infectious yaws showed florid skin lesions. Of 101 serum samples from such patients, 100 had a positive reaction in one or more treponemal tests. The Treponema pallidum haemagglutination assay was found to be the most sensitive test (97% positive) in detecting antibodies against Treponema pallidum subsp. pertenue, followed by the fluorescent treponemal antibody absorption test (94%), the Venereal Disease Research Laboratory test and the TmpA enzyme immunoassay (91%), and analysis by Western blot using Treponema pallidum antigens (88%). Of 42 asymptomatic contacts of yaws patients 32 showed positive reactions in one or more tests, indicating that many people in the investigated region have been infected with treponemes. Eight new Treponema pallidum subsp. pertenue strains were isolated from yaws skin lesions. In vitro amplification of treponemal DNA and hybridisation with specific DNA probes showed that all eight strains were identical with Treponema pallidum subsp. pertenue CDC 2575, with regard to the subsp. pertenue specific tyfl gene.