title: A stochastic model of the bovine spongiform encephalopathy epidemic in Canada.
abstract: Bovine spongiform encephalopathy (BSE) appeared in the United Kingdom in the mid 1980s, and has been attributed to the use of meat and bone meal (MBM) in cattle feed contaminated with a scrapie-like agent. Import of infectious materials from a country where BSE has occurred is believed to be the major factor underlying the spread of the BSE epidemic to other countries. This study presents a new stochastic model developed to estimate risk of BSE from importation of cattle infected with the BSE agent. The model describes the propagation of the BSE agent through the Canadian cattle herd through rendering and feeding processes, following importation of cattle with infectious prions. This model was used estimate the annual number of newly infected animals each year over the period 1980-2019. Model predictions suggested that the number of BSE infections in Canada might have been approximately 40-fold greater than the actual number of clinically diagnosed cases. Under complete compliance with the 2007 ban on feeding MBM, this model further predicts that BSE is disappearing from the Canadian cattle system. A series of sensitivity analyses was also conducted to test the robustness of model predictions to alternative assumptions about factors affecting the evolution of the Canadian BSE epidemic.
authors.affiliation: a Department of Mathematics , University of Texas Rio Grande Valley , Edinburg , Texas , USA.|b McLaughlin Centre for Population Health Risk Assessment , University of Ottawa , Ottawa , Ontario , Canada.
authors.forename: Tamer
authors.initials: T
authors.lastname: Oraby
authors.affiliation: b McLaughlin Centre for Population Health Risk Assessment , University of Ottawa , Ottawa , Ontario , Canada.|c Department of Community and Environmental Health, College of Public Health and Health Informatics , King Saud University for Health Sciences , Riyadh , Saudi Arabia.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Al-Zoughool
authors.affiliation: d School of Epidemiology, Public Health and Preventive Medicine , University of Ottawa , Ottawa , Canada.
authors.forename: Susie
authors.initials: S
authors.lastname: Elsaadany
authors.affiliation: b McLaughlin Centre for Population Health Risk Assessment , University of Ottawa , Ottawa , Ontario , Canada.|d School of Epidemiology, Public Health and Preventive Medicine , University of Ottawa , Ottawa , Canada.|e Risk Sciences International , Ottawa , Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
mesh_terms: D000818:Animals; D002170:Canada / Q000453:epidemiology; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000453:epidemiology* / Q000209:etiology; D058872:Epidemics; D008962:Models, Theoretical; D012307:Risk Factors; D013269:Stochastic Processes