Resolve Lassa Fever Persistence: A Compartmental Model with Environmental Virus-Host-Vector Interaction.

Lassa fever (LF), caused by the Lassa virus and transmitted primarily by Mastomys natalensis rodents, is a severe hemorrhagic disease endemic to West Africa, particularly Nigeria, with significant morbidity and mortality rates. This study develops a dynamic model for LF, incorporating crucial but often overlooked factors such as vertical transmission in rodents, surface contamination, and asymptomatic human carriers. Persistence of the disease is proved analytically. Using data from Nigeria, the impact of various control measures is assessed. Results of the study reveal that asymptomatic individuals are key drivers of LF and that including additional LF virus transmission pathways, e.g., vertical transmission and environmental contamination, increases the estimated reproduction number threefold compared to previous studies. The full model and rodent-involved sub-models show the highest disease prevalence, underscoring the need to address rodent involvement for effective control. Effective LF control using only rodent control measures requires maintaining rodent populations below a specific threshold. Additionally, a multifaceted approach, combining antiviral treatment, environmental disinfection, and personal protective equipment, significantly enhances disease control, while the introduction of a competitor rodent species can drastically reduce human and rodent infections. Ultimately, the study underscores the need for integrated, multifaceted strategies, including targeting rodents, asymptomatic cases, and comprehensive treatment and disinfection protocols, for effective LF management.