title: Estimating the Reproduction Number of Ebola Virus (EBOV) During the 2014 Outbreak in West Africa.
abstract: The 2014 Ebola virus (EBOV) outbreak in West Africa is the largest outbreak of the genus Ebolavirus to date. To better understand the spread of infection in the affected countries, it is crucial to know the number of secondary cases generated by an infected index case in the absence and presence of control measures, i.e., the basic and effective reproduction number. In this study, I describe the EBOV epidemic using an SEIR (susceptible-exposed-infectious-recovered) model and fit the model to the most recent reported data of infected cases and deaths in Guinea, Sierra Leone and Liberia. The maximum likelihood estimates of the basic reproduction number are 1.51 (95% confidence interval [CI]: 1.50-1.52) for Guinea, 2.53 (95% CI: 2.41-2.67) for Sierra Leone and 1.59 (95% CI: 1.57-1.60) for Liberia. The model indicates that in Guinea and Sierra Leone the effective reproduction number might have dropped to around unity by the end of May and July 2014, respectively. In Liberia, however, the model estimates no decline in the effective reproduction number by end-August 2014. This suggests that control efforts in Liberia need to be improved substantially in order to stop the current outbreak.
authors: Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.
authors: Christian L
authors: CL
authors: Althaus
references: Biometrics. 2006 Dec;62(4):1170-7
references: 17156292
references: Epidemiol Infect. 2007 May;135(4):610-21
references: 16999875
references: N Engl J Med. 2014 Oct 9;371(15):1418-25
references: 24738640
references: Science. 2014 Sep 12;345(6202):1369-72
references: 25214632
references: J Theor Biol. 2004 Jul 7;229(1):119-26
references: 15178190