Epidemics in Populations of Wild Ruminants: Anthrax and Impala, Rinderpest and Buffalo in Lake Manyara National Park, Tanzania

Abstract

In this paper we describe two major epidemics in wild mammals in a National Park in Tanzania, East Africa. An anthrax outbreak killed more than 90% of the impala population, and rinderpest some 20% of the number of buffalo. The two epidemics showed different patterns: anthrax continued for nearly a year, while the rinderpest outbreak lasted a few weeks only. However, both started at the end of the dry season, and in the discussion attention is given to the ecological conditions leading to the outbreak of disease. We conclude that epidemics in this Park had a more severe impact on the study populations than predation had, and we suggest that diseases are very important agents of natural selection. This means that in the study of ecology more attention should be given to disease and also that small nature reserves can depauperate easily if recolonization is prevented.