Epidemiological characteristics of Ebola virus disease epidemic in Sierra Leone

Objective To understand the epidemiological characteristics of Ebola virus disease (EVD) epidemic in Sierra Leone and the reasons for epidemic control failure, provide evidence for the prevention and control of emerging and imported communicable disease in China in future. Methods Descriptive epidemiological analysis was conducted on the EVD epidemic data published by World Health Organization (WHO) and the Ministry of Health and Sanitation of Sierra Leone. Results A total of 11 446 EVD cases were reported, including 3546 deaths, as of 1 March 2015. The morbidity was 180.6/lakh, the mortality was 55.9/lakh. Five stages of the epidemic were observed, i.e. silent and slow transmission, outbreak, sharp rise, sharp decline and decline in fluctuating. The EVD cases were first reported in Kailahun in southeastern area, then in Port Loko in northwestern area. EVD spread rapidly to all the areas in the country. The data revealed sex differences in the incidence (P=0.01), however the morbidity increased with age (2=2136.07,P0.001). The morbidity in health workers was higher than national level (P0.001). Conclusion The main reasons for failure in control of the epidemic in Sierra Leone included: the fall behind economy, traditional custom, limited prevention and control resources and poor implementation of early prevention and control measures. The lessons learnt from EVD prevention and control in Sierra Leone are important for the prevention and control of emerging and imported communicable diseases in China.