Public health surveillance systems in Senegal have been established to monitor disease outbreaks and implement timely interventions. However, their effectiveness and reliability require rigorous methodological assessment. A randomized field trial was conducted among 1000 healthcare facilities across Senegal. Surveillance data were collected on influenza-like illnesses, and outcomes were measured by comparing reported cases with actual laboratory-confirmed cases. The analysis revealed that the surveillance systems had a sensitivity of 85% in detecting influenza outbreaks, indicating a moderate level of reliability. While the systems showed promise, further improvements are needed to enhance their detection accuracy and timeliness. Continuous monitoring, regular calibration exercises, and technological upgrades should be implemented to improve system performance. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.