Ecological parasitism of baboons and lions

Thesis

This thesis investigates the epidemiology of intestinal parasites in wild populations of two social animals, olive baboons (Papio anubis) in Gombe Stream National Park, Tanzania, East-Africa, and lions (Panthera leo) in the Serengeti and Ngorongoro-Crater, Tanzania. These populations have been observed for over 20 years and detailed information on individual hosts was available for analysis with the parasitological data allowing to address questions about the relationship of host genetics and social behaviour to parasite infection.

The baboons were infected with seven different helminths as well as two types of protozoans. Fifteen morphologically different parasites were found in the lions. All baboons and almost all lions were parasitized. Parasite distribution in both host species was overdispersed. Spatial differences in parasite infection in the baboons and lions emerged as the strongest effect on heterogeneity of infection. Parasites of both host species showed seasonal and temporal variation. Parasite-parasite associations did not appear to have a strong impact on overall patterns of infection in either baboons or lions. Across all parasite taxa, age (with one exception in baboons), sex, reproductive status and group size had little significant influence on parasite burden. For baboons age-prevalence and age-severity profiles resembled those for the same parasites in humans. Correlations between baboon social rank and parasite burden were equivocal. Parasite infection was not correlated with size of baboon female genital swelling. Two lion populations were compared, an inbred and an outbred. Only one parasite, Spirometra spp., had a significantly higher prevalence in the inbred population, contrary to expectations.

Results of this study suggest that any effects on levels of infection in these wild populations due to social behaviour, genetics, sex and reproductive effort may be masked by the stronger influence of environmental and/or behavioural components of exposure, at least in the short term. This implies that the importance of factors such as genetics or social behaviour on infection may not always be apparent and may be dependent on the details of the local ecology of both host and parasite at the time the system is studied.

Authors: M�ller-Graf, C

• DOI: 10.5287/ora-gpgbwxzz0
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford