Bifurcation and Stability Analysis of Nipah Virus Transmission with Imperfect Vaccination

The Nipah virus (NiV) is a highly fatal zoonotic disease that poses a serious public health threat, particularly in Southeast Asia. This study analyses its transmission dynamics using an SVEIRD compartmental model incorporating imperfect vaccination. The model formulation explicitly accounts for key transmission routes, including direct contact and unprotected exposure to NiV-infected deceased bodies, with an exposed compartment representing the incubation period. The basic reproduction number (R₀) is derived using the next-generation matrix method. The dynamical analysis identifies two equilibrium points: the disease-free equilibrium (DFE) and the endemic equilibrium (EE). The DFE is shown to be globally asymptotically stable when R₀< 1, ensuring disease extinction. When R₀> 1, the DFE becomes unstable and a unique EE emerges. The global asymptotic stability of the EE is established by constructing a suitable Lyapunov function, confirming persistent endemicity. The system undergoes a forward bifurcation at R₀= 1. Numerical simulations corroborate all analytical findings. These results highlight the critical role of vaccination coverage and public health interventions in controlling Nipah virus outbreaks.