The association of selected climatic factors with natural alimentary parasites of the dog

In an effort to define the effects of the natural climate on the infection rates of canine alimentary parasites, a fecal flotation examination for alimentary parasites was performed on 2093 domesticated dogs during a 15-month period at Fort Leonard Wood, Missouri. Concurrently, 15 climatic variables were collected for comparison with the frequency of parasitism. The frequency of natural mono- and multi-infections with coccidia ( Isospora spp.), ascarids ( Toxocara canis and Toxascaris leonina), hookworms ( Ancylostoma caninum), and whipworms ( Trichuris vulpis) was determined and used to evaluate the randomness of multi-infections. In comparing parasitisms with the climatic factors, a complex bioclimatic relationship was found. The relationship was dependent on the parasitic agent(s) and the relative time frame. Natural climatic conditions influenced the ability of Isospora spp. to multi-infect hosts and strongly influenced the infection rate of Ancylostoma caninum. The study suggests that there is a bioclimatic interaction involving both the canine host and the parasite's extra-host life stages.