Efficacy and safety of praziquantel against Schistosoma haematobium in the Ikata-Likoko area of southwest Cameroon.

Background: Schistosomiasis remains a parasitic infection of public health importance especially in Africa south of the Sahara including Cameroon. Chemotherapy using praziquantel has been the most effective and widespread control measure used. However, there are reports of reduced efficacy of the drug. The aim of this study was to assess the efficacy and safety of praziquantel against Schistosoma haematobium among infected individuals in the Ikata-Likoko area of southwest Cameroon. Following a baseline study, S. haematobium egg load was determined using the urine filtration technique and microscopy. Participants were treated with a unique dose of praziquantel of 40 mg/Kg body weight. A control test was carried out on the 42nd day post-treatment to determine the proportion of positive participants with viable eggs (cure rate) and the egg loads. The egg loads obtained during the control and at baseline were used to calculate the egg reduction rate (ERR) used as the main indicator of praziquantel efficacy according to the WHO, 2013 protocol.

Results: At baseline, the prevalence of S. haematobium was 34.3% (177/516). Out of these a total of 174 participants aged between 4 and 76 years were recruited into the study. A total of 130 participants came for follow up on day 42. Among them, 22.3% (29) were positive for eggs of S. haematobium but none of the eggs were viable giving a cure rate of 100%. The overall mean egg load per 10 mL (MEL/10 mL) of urine reduced from 31 (1-400) at baseline to 6.0 (1-35) on day 42. The overall ERR was reduced (80.3%). However, the efficacy was satisfactory (ERR ≥ 90%) in females, children ˂ 5 years, and some localities and for individuals with heavy infection intensity. Fifteen (8.6%) of the participants presented minor adverse events including abdominal disorders, headache and vomiting but did not last for more than 24 h.

Conclusions: Treatment with praziquantel was efficacious and safe showing reduction in prevalence as well as mean egg load in some individuals with few adverse events recorded. The distribution of praziquantel in the area should be extended to other age groups and not just school-age children. A study with multiple drug doses and longer period of evaluation could reveal more information on praziquantel efficacy in the area.