Helminth parasites of impalas, Aepyceros melampus (Lichtenstein) (Ruminantia: Bovidae), in the Kruger National Park, South Africa: infection patterns from birth to adulthood
Keywords:wildlife parasites, helminths, impalas, prevalence, seasonal variation
There is limited information on the development of helminth burdens of wild ungulates. This study examined the development of helminth burdens of impalas from birth to adulthood in the southern Kruger National Park, South Africa, based on systematic monthly collections of helminths from lambs, yearling and adult impalas at two sites over the course of a year. Eighteen species of nematodes, two trematode taxa and three species of cestodes were collected. Six species, Cooperia hungi, Cooperioides hamiltoni, Impalaia tuberculata, Strongyloides papillosus, Trichostrongylus deflexus and Trichostrongylus thomasi, each collected from > 75% of the impalas, accounted for > 90% of adult gastrointestinal nematodes. Infection with adult nematodes occurred in the first month of life and all lambs were infected with adults and L4 larvae by the second month. Intensities of infection of adult nematodes and larvae in lambs increased until November when they were similar to those of yearlings and adults. Adult female impalas had a lower intensity of infection of adult nematodes than males from April to July, and a higher intensity of infection from October to December. Intensity of infection of L4 larvae was higher in adult females than adult males throughout the year. These patterns were seen in the most common nematodes, but were more variable for the less common nematodes, trematodes and cestodes. The ratio of L4 larvae to adult nematodes was lowest in lambs and highest in adult impalas. Our results emphasised the importance of age, sex and season as potential sources of variation in specific parasite burdens.