Host immune defenses are important components of host-parasite interactions that affect the outcome of infection and may have fitness consequences for hosts when increased allocation of resources to immune responses undermines other essential life processes. Research on host-parasite interactions in large free-ranging wild mammals is currently hampered by a lack of verified non-invasive assays. We successfully adapted existing assays to measure innate and adaptive immune responses produced by the gastrointestinal mucosa in spotted hyena (Crocuta crocuta) faeces, including enzyme-linked immunosorbent assays (ELISAs), to quantify faecal immunoglobulins (total IgA, total IgG) and total faecal O-linked oligosaccharides (mucin). We investigated the effect of infection load by an energetically costly hookworm (Ancylostoma), parasite richness, host age, sex, year of sampling and clan membership on immune responses and asked whether high investment in immune responses during early life affects longevity in individually known spotted hyenas in the Serengeti National Park, Tanzania. Faecal concentrations of IgA, IgG and mucin increased with Ancylostoma egg load and were higher in juveniles than in adults. Females had higher mucin concentrations than males. Juvenile females had higher IgG concentrations than juvenile males whereas adult females had lower IgG concentrations than males. High IgA concentrations during the first year of life was linked to reduced longevity after controlling for age at sampling and Ancylostoma egg load. Our study demonstrates that the use of non-invasive methods can increase knowledge on the complex relationship between gastrointestinal parasites and host local immune responses in wild large mammals and reveal fitness-relevant effects of these responses.

All methods used to produce this dataset have been described in detail in the research article.

Age= 1: juvenile; 3: adult

Sex= 1: male; 2: female

age = age at sampling

age_death = age of death

Rich_a = Number of parasite taxa present other than Ancylostoma

IMDSx = Sample scores of axis x of the immune profile Non-metric Multidimensional Scaling (NMS)

PMDSx = Sample scores of axis x of the parasite community Non-metric Multidimensional Scaling (NMS)