Parasite infection and host's behavior.
Résumé
Animal behavior and parasitism are more tightly linked, from an ecological and evolutionary point of view, than commonly thought. In the past 30 years, the growing field of evolutionary parasitology has tackled both proximate and ultimate answers to the following question: Why and how should the behavior of hosts exposed to the risk of a disease or that of parasitized hosts be altered? Altered behavior may simply be a symptom of disease without obvious connection with host resistance or parasite-transmission strategies. However, natural selection may have shaped behavior to avoid infection, get rid of parasites, or limit their pathogenicity. Alternatively, manipulative parasites may alter the behavior of their hosts in ways that increase their own fitness, at the expense of that of their hosts.