Predicting and Evaluating the Epidemic Trend of Ebola Virus Disease in the 2014-2015 Outbreak and the Effects of Intervention Measures

Guo, Zuiyuan; Xiao, Dan; Li, Dongli; Wang, Xiuhong; Wang, Yayu; Yan, Tiecheng; Wang, Zhiqi

Based on the SIR model, without any outbreak control or prevention measures, the total population number would decrease rapidly in a short period of time (Fig 1) . The net growth threshold values for the epidemic in Guinea (0.95), Liberia (1.01), and Sierra Leone (0.90) were all close to 1.0. Therefore, when the parameters of the model are held constant over a sufficiently long time period, the populations of the three countries decrease to constant levels, and the numbers of individuals in the s, i, and r blocks would oscillate with a periodic weakly dampened oscillation, and reach a positive dynamic equilibrium. The equilibrium points for s, i, and r were found to be 58.5%, 0.1%, and 41.1%, respectively, in Guinea, 54.6%, 0.1%, and 45.3%, respectively, in Liberia, and 49.5%, 0.1%, and 50.4%, respectively, in Sierra Leone.