Steve Bellan

Published on March 15, 2011 by

Counting Wildlife Carcasses: Anthrax surveillance in Etosha National Park, Namibia

In Etosha National Park, Namibia, the plains zebra and other herbivores experience outbreaks of anthrax. Anthrax is generally not considered to be a problem in Etosha but rather a natural regulating force in the ecosystem. However, the extent to which anthrax plays this role remains poorly understood. Estimating how many carcasses there really are will help us understand the extent to which anthrax regulates zebra and other host populations. The general approach we take is to think about all the factors that affect the probability any carcass is detected (distance from road, time since death, if and when that road was driven, how long carcasses are scavenged for) and then estimate the number of carcasses that were missed. Keeping track of both how we collect data, in addition to the items of interest themselves, can thereby allow us to tease much more information out of our data as well as avoid biasing our results. And with better estimates of anthrax incidence we can learn more about the role anthrax plays in Etosha and elsewhere.

Published on June 21, 2010 by

Building Capacity for Meaningful Epidemiological Modelling

Mathematical modelling is valuable in public health because it for example provides a way to evaluate strategies for controlling disease before actually trying such strategies in the field. By varying the values of model parameters, it is possible to ask questions such as: “How will the number of people getting sick during an influenza outbreak in Cape Town be affected if we give half of all sick people a drug that reduces their infectiousness by 50%?”. In May 2009, the first annual clinic on the Meaningful Modelling of Biological Data was organised at the African Institute for Mathematical Sciences (AIMS) in Muizenberg, South Africa.