Mathematical analysis of a modified Secirda-Sei model for Lassa fever transmission with contact tracing and awareness campaigns

Abstract

This study develops and analyses a deterministic Susceptible (S), Exposed (E), Contact traced (C), Infectious (I), Recovered (R), Dead (D), and Aware susceptible (A) individuals in the human population, Susceptible (S) and Exposed/Infectious (E/I) rodent population (SECIRDA-SEI) model for Lassa fever transmission that explicitly incorporates (i) contact tracing of exposed-butnot-yet-infectious individuals, (ii)  public awareness interventions that divert susceptible individuals into a low-risk awareness class, and (iii) multiple infection routes (human–human, rodent-human, and corpse-human/rodent). Analytical results establish the nonnegativity and boundedness of solutions, the existence of a disease-free equilibrium (DFE), and the derivation of the basic reproduction number, 𝑅0, via the next- generation matrix approach. A compact two-host reduction provides an interpretable closed-form for 𝑅0, showing that awareness and tracing rates directly suppress the effective reproduction potential. The DFE is locally asymptotically stable when 𝑅0 < 1 and unstable otherwise. Conceptual numerical illustrations demonstrate that moderate improvements in public awareness and contact tracing can jointly drive 𝑅0 below unity, thereby halting epidemic growth. These findings underscore the synergistic value of behavioural education, early case  detection, and ecological management in controlling Lassa fever in an endemic setting.