Science features Ebola mathematical modelling predictions


“If the epidemic in Liberia were to continue in this way until the 1st of December, the cumulative number of cases would exceed 100,000,” says ISPM’s Christian Althaus.

No one can be sure what the eventual toll of Ebola virus disease in West Africa will be. Science journalist Kai Kupferschmidt interviewed Christian Althaus and mathematical modellers in the USA, saying, “scientists across the world are scrambling to create computer models that accurately describe the spread of the deadly virus… the modelers all agree that current efforts to control the epidemic are not enough to stop the deadly pathogen in its tracks.”

Christian Althaus posted the first estimates of the reproduction number for Ebola virus in the Guinea, Sierra Leone and Liberia outbreaks. The effective reproduction number (Re) shows the potential for further spread after initial control efforts have started. In the Science article, Christian explained that, “’In Guinea and Sierra Leone, Re is close to 1 and the outbreak could be stopped if interventions improve a bit.’ In Liberia, Re has been near 1.5 the whole time. ‘That means work is only just beginning there.’” (see photo of model output, which suggests that Ebola virus is still spreading exponentially in Liberia).

The full Science article is online at Kupferschmidt also interviewed modellers Alessandro Vespignani in Boston, Ira Longini in Florida and Caitlin Rivers in Virginia. Vespignani, who uses data on international air travel in his model, says that Ghana, the UK and USA are most likely to introduce cases. Rivers, who has been modelling the effect of interventions, suggests that “In the most optimistic scenario, every contact of infected people is traced, and transmission in hospitals is reduced by 75%. Even that, while drastically reducing the number of Ebola deaths, did not push Re below one.”

Jeremy Farrar, director of the Wellcome Trust in London stressed the importance of mathematical modelling in infectious disease control to Kupferschmidt, “They can help agencies such as WHO predict the medical supplies and personnel they will need—and can indicate which interventions will best stem the outbreak.”

Christian Althaus is leading ISPM’s modelling efforts to predict the spread of Ebola virus and the potential impact of control interventions with statistician Sandro Gsteiger and epidemiologists Nicola Low and Fabienne Krauer. Matthias Egger is a member of the WHO Ebola Deployment and Data Collection working group, which will meet in Geneva on 4-5th September. 

If you are interested in additional sources of information about the Ebola virus epidemic, try:

World Health Organization: WHO provides regular updates and advice on its Global Alert and Response page.

ProMED compiles surveillance reports and news items about all infectious diseases, including Ebola. You can sign up for email alerts

Twitter: Yes, sign up and follow the latest Ebola virus news from news services and journals such as @nytimescience, @Promed-mail, @NatureNews, @ScienceMagazine, @bbcworldservice, @MicrobesInfect, and people like @davidfisman, @cmyeaton (Caitlin Rivers), @c_althaus, @nicolamlow.

Several major journals are allowing free access to all their published articles about Ebola virus, even the ones that usually charge for access: The Lancet, Science.