Nosocomial transmission of syphilis during haemodialysis in a developing country

Patients with end-stage renal disease (n = 187) secondary to diverse aetiologies who underwent haemodialysis (HD) between November 1996 and November 2000 were routinely screened for syphilis using the rapid plasma reagin (RPR) test and confirmed by means of a microhemagglutination assay for Treponema pallidum. All the confirmed syphilis patients were asymptomatic and were diagnosed serologically. A true seroprevalence of 6.9% (13/187) and a biological false seropositivity of 4.2% (8/187) for syphilis were recorded. Most (11/13) of the true seropositive patients were aged between 51 and 80 y. Whilst 10113 patients were true syphilis seropositive at the time of first HD, 3/13 patients became true seropositive an average of 12 months (range 10-14 months) after HD. Penicillin treatment was given to all 13 patients simultaneously only after the appearance of 3 new true syphilis seropositive cases. Complete seroreversion was observed in 4/10 patients in the pre-HD true syphilis seropositive group of presumptive transmitters who became RPR-negative, whereas the 3 new true seropositive cases showed a serial 4-fold decline in RPR titres 12 months after penicillin therapy, suggestive of an active disease with adequate therapeutic response. These results clearly indicate that latent syphilis is prevalent in long-term elderly HD patients. The true seroconversion of 3 new patients who had undergone HD for an average of 12 months is indicative of nosocomial transmission and the silently active nature of the disease, which necessitates regular monitoring of syphilis serology among HD patients.