The site distribution of adult strongyle parasites in the large intestines of horses in tropical Australia

In a study of gastro-intestinal parasites occurring in 57 horses in north Queensland, the locations where adult strongyle parasites were found in the large intestines were recorded in order to determine the preferred sites of these parasites. Differences were noted in the intensity of infection between the three sections of the large intestines with the ventral colon being the most heavily infected and having the highest number of species, followed by the dorsal colon and the caecum. The distribution of the various strongyle species between these sections of the intestines was not random. Many species showed preferences for particular sections. Changes were noted in site preferences of some species. These changes were related to season but not the age, sex and breed of the animal, nor the environment in which the animals were kept. These seasonal changes are discussed in relation to the epidemiology of equine strongyle infections in the area. There seems to be no differences in the basic site preference behaviour between strongyle species occurring in horses in the tropics and those from the temperate regions.