A cross-sectional study reveals complex associations between gastrointestinal parasite composition and faecal immune and inflammatory biomarkers in wildlife and livestock in Kenya.

Background: In landscapes where wildlife and livestock co-graze, hosts are often poly-parasitised with diverse nematode and protozoan communities. The relationships between chronic, endemic parasite infections and host immune response is still unknown in many species, particularly for wildlife. Faecal ecoimmunological biomarkers allow physiological changes to be monitored Methods: Here we used an exploratory, cross-sectional study to examine the relationships between faecal immunological biomarkers and gastrointestinal parasitism in six wild and four domestic species of ungulates co-grazing in Laikipia, Kenya (10 samples per species). We measured faecal IgA, IgG, bovine lactoferrin and equine IL-6 using in-house enzyme immunoassays, alongside DNA metabarcoding, PCR screening and faecal egg counts, to explore the impacts of parasite composition and load on gut mucosal health. We aimed to identify specific parasites or community characteristic that were associated with higher faecal biomarker concentrations by fitting gobal models and using stepwise selection to identify key parasite predictors. Results: Interestingly, a comparative immunology approach revealed that no one parasite was associated with a particular biomarker pattern across all host species. For example, the nematode Conclusions: This study provides an exploratory overview of the immune responses of wild and domestic herbivores, in association with natural multi-parasitic nematode and protozoan infections. Future research using comparative immunology approaches could improve our understanding of host immune phenotypes and the impacts of co-infections, improving decision making to promote animal health in shared landscapes.