Comparative efficacy of one versus two doses of praziquantel on cure rate of Schistosoma mansoni infection and re-infection in Mayuge District, Uganda

The current recommended control strategy for schistosomiasis is annual treatment using 40 mg/kg of praziquantel. However, praziquantel is only effective on adult worms and giving a second dose may increase its efficacy. We assessed the effect of one versus two doses of praziquantel on cure rate and re-infection with Schistosoma mansoni in a high endemic community along Lake Victoria, Uganda. To investigate the effect of the two regimens, 395 infected people were randomised into two groups; one received a single standard dose of praziquantel (Distocide 600 mg, Shin Poong Pharmaceuticals, Seoul, Republic of Korea), 40mg/kg body weight, while the other group received a second dose 2 weeks later. Cure rate and infection intensity were assessed 9 weeks after the first treatment using standard parasitological procedures. Re-infection levels were monitored 8 and 24 months after treatment. Those who received two doses were more likely to be cured (69.7) compared to those who received a single dose (47.9) ((2) 18.5, p 0.001). Geometric mean intensity (GMI) of infection at 9 weeks (eggs per gram of faeces [epg]) was 12.0 epg (CI95: 8.916.1) for individuals who received 2 doses and 22.1 epg (CI95: 16.928.8) for those in the single dose arm. Eight months after treatment, prevalence of re-infection for individuals in the double dose arm (61.6, CI95: 50.273.1) was not significantly different from that of those in a single dose arm (68.3, CI95: 59.976.8). The difference in GMI of re-infection for individuals in the single dose arm (33.8 epg, CI95: 23.249.3) and those in the double dose arm (34.5 epg, CI95: 24.748.1) was not significant. Twenty four months after treatment, prevalence of re-infection was not significantly different. The difference in GMI of re-infection for those in the single dose arm (57.5 epg, CI95: 33.997.5) and those in the double dose arm (42.2 epg, CI95: 29.959.6) was also insignificant. Our results suggest that a second dose of praziquantel given 2 weeks after the first dose improves cure rate and reduces S. mansoni infection intensity. However, there is no added advantage on reduction of S. mansoni re-infection by administering two doses of praziquantel. NCT00215267.