Modelling campylobacteriosis dynamics: Impacts of contaminated animal products and environmental decontamination interventions

Campylobacteriosis is responsible for approximately 500 million cases of illness globally each year. Globally, human campylobacteriosis infections and contaminated animal products cause an estimated loss of 8.6 and 12.6 billion US dollars annually, respectively. The disease is transmitted through consumption of contaminated foods and water, licking unsanitary hands and contact with infected hosts. As global demand for animal products like meat and milk continues to grow, the transmission of campylobacteriosis through these products has become a critical concern. This study aims at utilising mathematical modelling and analysis techniques to quantify the effects of contaminated animal products and environmental decontamination interventions on campylobacteriosis dynamics in host populations. A mathematical model as a system of ordinary differential equations is proposed with human and cattle populations and contaminated animal products. The next-generation matrix method is applied to compute the effective reproduction number $R$ that describes disease persistence and extinction. The global stability of equilibria states is examined using the Lyapunov stability theory. The uncertainty and sensitivity of model parameters are examined using the Latin Hypercube Sampling and Partial Rank Correlation Coefficient methods. Model fitting and parameter estimations are performed using the least squares method alongside the human cases from January to August for the years 2017 to 2020 in the EU. The analysis indicates that the disease-free and endemic equilibria are globally asymptotically stable whenever $R<1$ and $R>1$, respectively. The numerical results show that the ingestion rates of contaminated animal products, shedding rates and the natural replication rates of Campylobacter jejuni bacteria are directly proportional to $R$, while the environmental cleanliness and the decay rate of Campylobacter jejuni bacteria are inversely proportional to $R$. In order to reduce the impact of contaminated animal products, the study recommends a couple of strategies for reducing shedding rates, killing bacteria, and vaccinating infected hosts.