Associations of, and interactions among, Helminths in coyotes (Canis latrans)
LE3 .A278 2021
Master of Science
Variables that can influence health include age, sex, diet, condition, and parasites. Parasitism, by definition, is a relationship in which a parasite exploits (e.g., by feeding on tissue) its host. Animals come in contact with parasites frequently, including from feeding, and interacting with conspecifics and their environment, which may result in individuals harbouring multiple species of parasites. Parasites can cause hosts to upregulate their immunity, to spend energy repairing tissue damage, and to lose nutrients. It is assumed that these three demands will decrease host health. To evaluate this, I quantified coyote health using three indices, and tested if host health was related to helminth intensities and species richness. There were no significant relationships between log-intensity tracheal nodules or Taenia sp. tapeworms and the three measures of host health (Ps >0.07); however, there was a significant negative relationship between log-intensity Crenosoma vulpis fox lungworms and condition (P= 0.04), and log-intensity Uncinaria stenocephala hookworms and size (P= 0.02), condition (P= 0.04), and kidney-femur fat index (P< 0.01). Next, I tested if coinfections were independent, and if helminth interactions were positive, negative, or negligible. Coyotes infected with tracheal nodules (Oslerus osleri) were more likely to be also infected with fox lungworms (Crenosoma vulpis; P= 0.0002), but four other pairs of helminth infections appeared to be independent of one another (Ps>0.18). Interactions were undetectable for four of the five helminth combinations tested (P>0.13). However, mean intensities of Taenia sp. tapeworms were significantly higher in coyotes that also had hookworms (Uncinaria stenocephala; P= 0.03), consistent with a positive numeric response. This study found significant negative relationships between host health and some helminths, but associations were not universal for all species. Parasites are of concern for all organisms including humans, and investigating these relationships are important in improving our understanding of how to protect ourselves against infection.
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