Gastrointestinal parasite community structure in Procyon lotor: relationships to demographic variables, host condition, and immune response

Abstract

Historically, the study of parasites has been limited to their interactions with their hosts and has often ignored the impact that interactions between different species of parasites can have on hosts. In wild populations, however, hosts are often simultaneously infected with a number of parasite species, and the ensuing interactions may have significant effects on host and population health. Raccoons (Procyon lotor) are an ecologically important species living in close connection with human settlement and often subject to management practices. These animals also harbor a wide variety of micro- and macro-parasites, many of which can go on to infect other species including humans. Using a data set developed using cross-sectional sampling of wild raccoons from the Burlington, VT area, I examined the relationships of host condition, demographic variables, and immune profile to the gastrointestinal parasitic community composition. I found evidence for a primarily facilitatory association between nematodes and coccidia. Results based on demographic variables indicate that parasite prevalence and burdens are roughly equal across the sexes, ages, and lactation statuses, with any differences seen in this study likely due to the timing of fieldwork and methodology to calculate nematode burden. Immune analyses indicated immune-mediated facilitation between the two parasite types, but further research is needed. Body mass index was not shown to be associated with infection status or burden, suggesting infection tolerance, but this may be confounded by host access to anthropogenic food sources. Conclusions drawn from this study may help inform further research as well as wildlife management and public health efforts.