LIFE CYCLE, HOST UTILIZATION, AND ECOLOGICAL FITTING FOR INVASIVE LANCET LIVER FLUKE, DICROCOELIUM DENDRITICUM, EMERGING IN SOUTHERN ALBERTA, CANADA
LIFE CYCLE, HOST UTILIZATION, AND ECOLOGICAL FITTING FOR INVASIVE LANCET LIVER FLUKE, DICROCOELIUM DENDRITICUM, EMERGING IN SOUTHERN ALBERTA, CANADA
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DOI：
10.1645/16-140
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发表时间：
2017-06-01
影响因子：
1.3
通讯作者：
Goater, Cameron P.
中科院分区：
文献类型：
--
作者：
van Paridon, Bradley J.;Gilleard, John S.;Goater, Cameron P.
在进化过程中，寄生虫分布在其原生宿主和地理范围之外的扩张一再发生。当代的例子包括新出现的传染病，其中许多对人类、家畜和野生动物种群构成威胁。理论预测，寄生虫与复杂的生活史将是罕见的EID由于在每个生活史阶段的主机专业化所施加的限制。与此理论的预测相反，我们报告了2个新的中间宿主在3-主机生活周期的肝吸虫Dicrocococoadendriticum在柏树山省立公园，阿尔伯塔，加拿大。细胞色素氧化酶1（cox 1）的线粒体基因序列分析的结果确定的陆生蜗牛Oreohelix surudis和蚂蚁Formica aserva的第一和第二中间主机，分别在该地区。这些中间宿主，以及它们生活史中所使用的一套家养和野生哺乳动物食草动物，都不存在于D. dendriticum在欧洲我们的调查结果显示，D。O.样本中的树枝状突起。Subrudis的平均囊蚴密度在4%~ 10%之间; aserva在33和41之间变化（n = 163，平均值+/- SD = 38 +/- 35）。这些结果是第一次描述完整的生活周期新兴柳叶刀吸虫在北美西部。多层次的生态拟合的过程中，柳叶刀吸虫具有预先存在的性状，利用宿主资源，而不是宿主物种，在每个生命周期阶段提供了一个机制，建立这种复杂的生命周期在一个新的栖息地和新的主机。
The expansion of parasite distributions outside of their native host and geographical ranges has occurred repeatedly over evolutionary time. Contemporary examples include emerging infectious diseases (EIDs), many of which pose threats to human, domestic animal, and wildlife populations. Theory predicts that parasites with complex life cycles will be rare as EIDs due to constraints imposed by host specialization at each life-cycle stage. In contrast to predictions of this theory, we report 2 new intermediate hosts in the 3-host life cycle of the liver fluke Dicrocoelium dendriticum in Cypress Hills Provincial Park, Alberta, Canada. Results of sequence analysis of the cytochrome oxidase 1 (cox1) mitochondrial gene identified the terrestrial snail Oreohelix subrudis and the ant Formica aserva as first and second intermediate hosts, respectively, in the region. Neither of these intermediate hosts, nor their suite of domestic and wild mammalian grazers used in the life cycle, occurs within the native range of D. dendriticum in Europe. Our results from host surveys show that the prevalence of D. dendriticum in samples of O. subrudis varied between 4% and 10%, whereas mean metacercariae intensity in F. aserva varied between 33 and 41 (n = 163, mean +/- SD = 38 +/- 35). These results are the first to describe the complete life cycle of emerging lancet fluke in western North America. The process of multi-level ecological fitting, in which the lancet fluke possesses pre-existing traits to utilize host resources, rather than host species, at each life-cycle stage provides a mechanism for the establishment of this complex life cycle in a novel habitat and in novel hosts.