Evans Omondi, PhD

Friday 30 June, 16:45 – 18:00

Abstract: This paper presents a differential equation model which describes the transmission dynamics for brucellosis in cattle (livestock) and humans. The model aims to draw epidemiological and theoretical inferences on how to eliminate brucellosis from both the cattle and human populations. We first determine the effective reproduction number R0 and make sensitivity analysis of the effective reproduction number in terms of some parameters. A global sensitivity analysis (GSA) is performed in order to investigate the influence of all the model parameters on the model outcome (model variables of interest). The numerical simulations were carried out to reflect the known prevalence of brucellosis in Marsabit County in Kenya which stabilized at 13% in the cattle population and 43% in the human population in the absence of intervention. Vaccination coverage that corresponds to > 70% reduces prevalence in the cattle population to 6% and that in humans to 15% after 10 years of vaccination accounting for 70% and 65% reduction in prevalence, respectively. Observing biosecurity measures that correspond to reducing the baseline contact rate in our model by at least 10% reduces the prevalence for brucellosis by 70% and 68%, in cattle and humans after 8 years, respectively. Furthermore, educational campaigns that correspond to reducing the baseline contact rate between the human and the infected cattle by at least 90% reduces the prevalence for brucellosis in humans by 50%. A combination of vaccination, biosecurity and educational campaigns have the potential of eliminating brucellosis within a period of less than 10 years. The factors that are obviously important to the success of the brucellosis control efforts are the enhancement of effectiveness of these intervention measures, and ensuring their high adherence/coverage.

About: Evans is a Senior Lecturer at the Institute of Mathematical Sciences at Strathmore University in Kenya. He holds a PhD in Mathematical Biology from Strathmore University, an MSc in Mathematics from Stellenbosch University in South Africa, an MSc in Mathematical Sciences from AIMS-South Africa in collaboration with Stellenbosch University, and a BSc in Applied Statistics with Computing from the University of Eldoret. His primary research interests lie in building mathematical and statistical models applied in management and containment of infectious diseases.