PSA 307, Friday February 18th 2005, 3.40p.m-4.30p.m

Speaker: Sze-Bi Hsu,
              Institute of Applied Mathematics, National Tsing-Hua University, Taiwan,
              and Texas A&M University

Title: Modeling Intervention Measures and Behavior Change During a
        Severe Acute Respiratory Syndrome Outbreak

Abstract.   The Severe Acute Respiratory Syndrome (SARS) epidemic of
               November 2002 to June 2003 came with much fanfare and left swiftly,
               resulting in more than 8000 probable cases worldwide and 774
              casualties.
                Many had believed that the simple age-old system of quarantining those
              individuals suspected of being infected had been instrumental in quick
              containment of the infections. In this talk,  we propose a
              differential equations model which includes quarantine as well as other
              intervention measures by authority, including those to prevent nosocomial
              infections and  decrease contacts among general public. We also consider the
              possible behavior change by general populance in reaction to these measures.
              For the general model, the  basic reproduction number is derived. Full global
              mathemtical analysis is provided for the model without quarantine. For the
              model with quarantine, local stability analysis and the prediction of the
              outcomes are  given. The results indicate that the measures will be effective in
              reducing infections only if the quarantined/isolated SARS patients can successfully
              reduce their contact rate and/or transmission probabilities for such contact. Hence
              diligent adherence to these measures is essential to any intervetion
              measures.