Impact of surveillance in human-to-human transmission of monkeypox virus

Abstract

Monkeypox has become the major orthopoxvirus causing infection since the eradication of smallpox 1980s. In this paper, we developed a compartmental mathematical model that describes the transmission dynamics of the monkeypox virus incorporating contact tracing (surveillance), pre-exposure, and post-exposure vaccination. It is shown that the model is mathematically well posed and can be used to study, predict, and make suggestions on the transmission and control of the monkeypox virus. The qualitative analysis of the model shows that the model exhibits two equilibrium states: monkeypox-free and endemic equilibriums. In addition to these equilibria, the model undergoes backward bifurcation. The effective reproduction number (control parameter) is determined and the stability of two equilibriums is established using the calculated reproduction number. The monkeypox-free equilibrium is locally and globally asymptotically stable when R-eff<1. The endemic equilibrium on the contrary exists if R-eff>1 and there is a small or negligible number of vaccinated individuals (about 0.035% of the population) per week. The endemic equilibrium is globally stable under certain conditions. Model fitting and parameter estimations are performed using the least-squares curve fittings. The simulation result of the model shows that in the absence of disease surveillance, the number of un-traced infectious individuals will grow and this can lead to a large number of new infections that may lead to the outbreak of the disease. However, to avoid the outbreak, the model incorporated isolation of those un-traced infectious individuals who show symptoms of the disease. The result also shows that contact tracing, disease surveillance isolation, and vaccination can entirely stall human-human monkeypox virus transmission.