Samridhi Rijal , Peter Neuhaus , Jack Thorley , Nigel Caulkett , Susan Kutz , Kathreen E. Ruckstuhl
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引用次数: 0
Abstract
Males and females in sexually dimorphic species show differences in their physiology and behaviour due to differences in energetic investment into reproduction and soma. This means that the two sexes may show different patterns of parasitism at different times of the year. In this study, we evaluate the abundance of fecal eggs and larvae of 5 parasite types (Strongyles, Nematodirus spp., Marshallagia marshalli., Protostrongylus spp. lungworms, and Eimeria spp.) in relation to season and sex in Rocky Mountain bighorn sheep (Ovis canadensis). We use fecal egg counts (FEC) as a proxy for infection intensity. Parasite FECs differed between male and female bighorn sheep and varied with season. We found pronounced fluctuations in fecal egg counts of various parasite species in males and females across different seasons and reproductive stages. Strongyle counts were significantly higher during late gestation and lactation/summer, and particularly pronounced in males. Nematodirus counts were highest during late gestation in females and during the rut in males. Marshallagia counts peaked during late gestation in females and during the rut in males. Protostrongylus spp. lungworm counts were highest during late gestation in females and in males during lactation/summer and the rut. Eimeria oocyst counts varied across seasons, with higher counts in males during the rut and in females during winter and late gestation. Additionally, significant differences in Strongyle counts were observed between coursing and tending rams, with tending rams exhibiting higher counts. We discuss why the sexes might differ in FECs and suggest that differences between FECs of the parasites across seasons may be due to different life cycles and cold tolerance of the parasites themselves.
期刊介绍:
The International Journal for Parasitology: Parasites and Wildlife (IJP-PAW) publishes the results of original research on parasites of all wildlife, invertebrate and vertebrate. This includes free-ranging, wild populations, as well as captive wildlife, semi-domesticated species (e.g. reindeer) and farmed populations of recently domesticated or wild-captured species (e.g. cultured fishes). Articles on all aspects of wildlife parasitology are welcomed including taxonomy, biodiversity and distribution, ecology and epidemiology, population biology and host-parasite relationships. The impact of parasites on the health and conservation of wildlife is seen as an important area covered by the journal especially the potential role of environmental factors, for example climate. Also important to the journal is ''one health'' and the nature of interactions between wildlife, people and domestic animals, including disease emergence and zoonoses.