Conclusion
Interactions among parasites in naturally coinfected animals are
well-recorded. Incorporating multiple guilds of parasites in a
comprehensive network has, however, been less commonly reported,
particularly in model species. Every parasite surveyed in this wild host
population was implicated in an association with at least one other
parasite, with multiple cross-guild interactions observed. Interactions
which may explain many of these associations are potentially
immune-mediated, as most of the species pairs exhibiting associations
exist within different niches. C. hepaticum and T. muris
impart well-characterised changes to immune state in infection models
which may be evident here. While potential pathogens such as viruses are
not included in this study, we have demonstrated the importance of
accounting for coinfection when studying parasitic infection in wild
populations, and the prevalence of cross-guild associations which may
not be always accounted for during studies of natural infections. This
point is highlighted by the prominence of associations between C.
hepaticum, an often overlooked infection in wild rodent populations,
and ectoparasites, bacteria, protozoa and helminths within other niches.
The associations reported here are based on cross-sectional data; this
work would be greatly improved with the addition of longitudinal data,
to determine causality in associations, examine the significance of
order of infection, and obtain a clearer picture of the mechanisms
underlying coinfection dynamics.