Modeling the SARS Outbreak in Toronto, Canada

In the last century rapid spread of disease has become a critical threat due to increasing interaction on a global scale. Quick development of simple and effective models with limited data can be a crucial part of determining exactly how and for how long to handle the outbreak of a disease. The outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003 in Toronto, Canada differed from other outbreaks of the disease. Two outbreaks were observed, most likely linked to a relaxation in preventative strategies. Better predictors of how long an outbreak can last and how to best counteract new infections is key to preventing cases like this in the future. By examining a data set consisting only of counts of new infections each day and their likely method of infection (i.e. family contact, healthcare setting, travel, etc.) a multi-group compartmental model was developed to estimate the rate of infection as well as the basic reproduction number. The model was used to determine new infections, deaths, and recoveries for each day and also to determine the best methods for preventing new infections, such as quarantine, healthcare procedures, and isolation.