Nantambi/Modeling-Undetected-RVF-Transmission

SEIR simulation model of Rift Valley Fever transmission estimating the hidden burden of undetected human infections and evaluating sentinel screening of high-risk occupations as an early warning strategy for circulating RVF in Uganda. The project aimed to estimate the burden of undetected human Rift Valley Fever infections and evaluate sentinel screening of high-risk occupational groups as an early detection strategy. Findings indicate persistent low-level RVF circulation with substantial under-ascertainment under passive surveillance, while targeted screening markedly improves early detection. 1. Compartment Dynamics at Equilibrium Interpretation: The trajectories of the Susceptible (S), Exposed (E), Infectious (I), and Recovered (R) compartments converge toward a stable endemic equilibrium with mild periodic oscillations. The exposed and infectious populations persist at low but non-zero levels, indicating continuous low-level transmission rather than epidemic fade-out. This suggests that RVF can circulate silently in the population over long periods, sustained by recurring zoonotic spillover and seasonal ecological drivers. The stable recovered compartment reflects ongoing accumulation of immunity following repeated low-intensity exposures. Implication: RVF transmission may remain cryptic between recognized outbreaks, reinforcing the likelihood of undetected infections in endemic settings. 2. Infectious Humans Over Time Interpretation: The infectious compartment shows sustained oscillations without collapse to zero, confirming persistent endemic transmission. Peaks are relatively small, indicating that infections rarely escalate into large outbreaks under baseline conditions. Instead, the model predicts continuous low-level incidence that may not trigger clinical suspicion or reporting. Implication: Passive surveillance systems that rely on severe symptomatic cases are likely to miss the majority of infections occurring at these low endemic levels. 3. Model Dynamics at Equilibrium (All Compartments) Interpretation: This figure demonstrates synchronized oscillatory behavior across all compartments. Susceptible individuals remain abundant, while exposed and infectious populations fluctuat …