Mathematical modeling of Lassa fever transmission dynamics with nosocomial and environmental pathways

Lassa fever remains a major public health concern in West Africa, with persistent outbreaks driven by zoonotic spillover, human-to-human transmission, and inadequate infection prevention practices in healthcare settings. In this study, we develop and analyze a deterministic mathematical model for Lassa fever transmission that incorporates zoonotic, community, nosocomial, and environmental transmission pathways. The effective reproduction number ( R e ) is derived and the local and global stability properties of the disease-free and endemic equilibria are established. The analysis of the endemic-equilibrium polynomial and numerical bifurcation results support a forward transcritical bifurcation at R e = 1 , with no evidence of backward bifurcation under the baseline parameterization. The local and global sensitivity analyses identify the most influential parameters governing the disease transmission and persistence. The results show that rodent-driven, community and healthcare-associated transmission rates contribute strongly to increasing R e , whereas treatment and natural recovery rates significantly reduce the spread of the disease. The analysis also reveals structural non-identifiability of the parameter combinations C β H , β E ξ H , and β e ξ B from R e alone. The numerical simulations further demonstrate that hospital infection control measures, rapid treatment initiation, and reduction of rodent-driven environmental contamination substantially decrease the prevalence of the infection. The findings highlight the critical role of integrated intervention strategies combining rodent control, environmental sanitation, patient isolation, the use of personal protective equipment, and strengthened healthcare infection prevention measures.