Risk Factors for Treatment Failure in Urogenital Schistosomiasis Following Praziquantel Administration in Zamfara State

Praziquantel treatment failure in urogenital schistosomiasis is a clinically important phenomenon with implications for elimination programme sustainability, and identification of associated risk factors in Northwest Nigeria is urgently needed. This analytical cohort study investigated risk factors for praziquantel treatment failure among schoolchildren with Schistosoma haematobium infection in Zamfara State. A total of 340 infected children aged 5 to 15 years received standard weight-adjusted praziquantel treatment and were followed up at 4 and 8 weeks post-treatment. Treatment failure was defined as persistent egg excretion greater than 50 percent of pre-treatment density at week 8. Baseline egg intensity, age, sex, reinfection exposure, and nutritional status were assessed as potential predictors. Treatment failure rate at week 8 was 14.7 percent, significantly higher than the WHO benchmark of less than 5 percent. High baseline egg intensity (greater than 500 eggs per 10 ml urine) was the strongest predictor (OR 4.2). Continued water contact after treatment was documented in 78.4 percent of treatment-failure cases. Stunted children had significantly higher failure rates, suggesting nutritional modulation of drug response. These findings call for intensified reinfection prevention messaging alongside praziquantel delivery and consideration of repeat treatment protocols for heavy-intensity infections in Zamfara State. Keywords: praziquantel treatment failure, Schistosoma haematobium, risk factors, Zamfara State, schistosomiasis.