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

The WHO has reported numbers of EVD cases (confirmed and suspected) and deaths due to EVD [20] . These data were used to compare the predicted values from the model to the actual data. The infection rate for patients in an uncontrolled environment (β I ), indicates the number of susceptible individuals to be infected by an EVD patient per unit time following a gamma distribution pattern; meanwhile, the β D , β P , and β R rates reflect an exponential distribution pattern. The numbers of EVD cases and EVD-related deaths predicted by the model were similar to the actual data (Fig 3) , indicating that the model simulated the epidemic pattern of EVD accurately. Modeling the effects of isolating close contacts on the epidemic trend of EVD Individuals in close contact with EVD patients are a high-risk population and are prone to infecting other susceptible individuals if they are not isolated and closely monitored. Therefore, quarantining the close contacts of EVD patients early is critical to control and prevent transmission of EVD. As shown in Fig 4A, quarantining close contacts of patients decreased the predicted incidence of EVD dramatically. By May 31 st , 2015, the cumulative number of EVD cases predicted without isolation of close contacts was 37% greater than the predicted number with isolation.