Epidemiology of parasitic protozoan infections in Soay sheep (Ovis aries L.) on St Kilda
Epidemiology of parasitic protozoan infections in Soay sheep (Ovis aries L.) on St Kilda
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DOI：
10.1017/s0031182006001144
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发表时间：
2007-01-01
期刊：
影响因子：
2.4
通讯作者：
Pemberton, J. M.
中科院分区：
文献类型：
--
作者：
Craig, B. H.;Pilkington, J. G.;Pemberton, J. M.
圣基尔达州赫塔的野生索伊羊 (Ovis aries L.) 种群是多种寄生虫群落的宿主，但之前对该种群的寄生虫学研究仅集中于后生动物物种。本文报告了对索伊羊中原生动物物种（包括小隐孢子虫、十二指肠贾第鞭毛虫和 11 种艾美耳球虫）的首次流行病学研究，历时 3 年在不同的宿主种群密度下进行。几乎所有原生动物种类的流行率和强度均随着宿主年龄的增长而显着降低，但颗粒状原虫例外，其流行率随着宿主年龄的增长而增加。小隐球菌的流行率似乎随宿主种群密度呈正向变化，但十二指肠隐球菌的流行率并未随密度而显着变化。自 2002 年宿主种群崩溃以来，大多数艾美耳球虫物种的感染水平都表现出明显的滞后性，需要长达 2 年的时间才能下降。 2002 年是寄主密度较低的一年，艾美耳球虫混合物种的强度和多样性最高。寄生虫多样性随着寄主年龄的增长而降低，并且在雄性中更高。就患病率而言，原生动物物种之间存在 5 个正配对关联。这项研究的结果强调了原虫感染可能影响携带不同寄生虫物种的野生宿主种群的寄生虫抗性进化。
The feral Soay sheep (Ovis aries L.) population on Hirta, St Kilda, is host to a diverse component parasite community, but previous parasitological studies of the population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprising Cryptosporidium parvum, Giardia duodenalis and 11 species of Eimeria in Soay sheep across 3 years of varying host population density. Prevalence and intensity of almost all species of protozoa significantly decreased with host age, with the exception of E. granulosa, which increased in prevalence with host age. The prevalence of C. parvum appeared to vary positively with host population density but that of G. duodenalis did not vary significantly with density. Most species of Eimeria showed a distinct lag in infection level following the host population crash of 2002, taking up to 2 years to decrease. Mixed Eimeria species intensity and diversity were highest in 2002, a year of low host density. Parasite diversity decreased with host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild host populations harbouring diverse parasite species.