Physiological and social consequences of gastrointestinal nematode infection in a nonhuman primate

Gastrointestinal nematodes are intensely studied models for host-pathogen interactions in wildlife, yet consequences of infections are not fully understood. Among the potential costs of nematode infection are physiological changes caused by immune system activation, reduction or reallocation of available energy, as well as potential social consequences in terms of decreased social activity or avoidance of infected individuals. We used experimental anthelmintic treatment to investigate effects of strongyle nematode infection in Barbary macaques (Macaca sylvanus), comparing 56 treated to 17 untreated individuals. Deworming success was monitored by coproscopy and infection probability estimated from patch occupancy models. Increasing strongyle infection probabilities were associated with increased fecal glucocorticoid metabolite levels and slightly decreased activity, and had no significant effect on energy balance quantified as urinary C-peptide levels. The frequency to approach into clos...