Figure 1. Disease mediation of a lion-zebra-grass tritrophic chain in the Etosha National Park ecosystem in Namibia.

The anthrax pathogen, Bacillus anthracis, accounts for a substantial number of deaths of zebra and other herbivores (including springbok, elephant, wildebeest), thereby providing a largess of resources for the scavenger community dominated by jackals, hyenas, and several species of vultures and corvids, not to mention lions themselves. (In the lower right picture is a zebra carcass a few hours after death from anthrax with vultures and jackals the first to arrive on the scene). Thus the microbe B. anthracis plays an important role in determining the ultimate structure of the Etosha herbivore-carnivore-scavenger foodweb.