Illera Juan Carlos, Emerson Brent C, Richardson David S
Island Ecology and Evolution Research Group, IPNA, CSIC, C/ Astrofísico Francisco Sánchez, 3, E-38206 La Laguna, Tenerife, Canary Islands, Spain.
Parasitol Res. 2008 Nov;103(6):1435-43. doi: 10.1007/s00436-008-1153-7. Epub 2008 Sep 2.
Exotic pathogens have been implicated in the decline and extinction of various native-island-bird species. Despite the fact that there is increasing concern about the introduction of diseases in island ecosystems, little is known about parasites in the islands of Macaronesia. We focus on Berthelot's pipit (Anthus berthelotii), an endemic and widespread Macaronesian bird species, using a combination of field studies and molecular techniques to determine: (1) the range and prevalence of avian pox and malaria in Berthelot's pipits throughout the species' distribution, (2) the genetic characterization of both parasites in order to ascertain the level of host specificity. We sampled 447 pipits across the 12 islands inhabited by this species. Overall, 8% of all individuals showed evidence of pox lesions and 16% were infected with avian malaria, respectively. We observed marked differences in the prevalence of parasites among islands both within and between archipelagos. Avian pox prevalence varied between 0-54% within and between archipelagos and avian malaria prevalence varied between 0-64% within and between archipelagos. The diversity of pathogens detected was low: only two genetic lineages of avian malaria and one lineage of avian pox were found to infect the pipit throughout its range. Interestingly, both avian malaria parasites found were Plasmodium spp. that had not been previously reported in the Macaronesian avifauna (but that had been observed in the lesser kestrel Falco naumannii), while the avian pox was a host specific lineage that had previously been reported on two of the Canary Islands.
外来病原体被认为与多种本土岛屿鸟类物种的数量减少和灭绝有关。尽管人们越来越关注岛屿生态系统中疾病的引入，但对马卡罗尼西亚群岛的寄生虫却知之甚少。我们以贝氏鹨（Anthus berthelotii）为研究对象，这是一种特有的、分布广泛的马卡罗尼西亚鸟类，采用野外研究和分子技术相结合的方法来确定：（1）在贝氏鹨整个分布范围内禽痘和疟疾的分布范围及流行率；（2）两种寄生虫的遗传特征，以确定宿主特异性水平。我们在该物种栖息的12个岛屿上对447只鹨进行了采样。总体而言，所有个体中分别有8%出现痘疹病变迹象，16%感染了禽疟疾。我们观察到，无论是在群岛内部还是群岛之间，各岛屿上寄生虫的流行率都存在显著差异。群岛内部和之间禽痘的流行率在0 - 54%之间变化，禽疟疾的流行率在0 - 64%之间变化。检测到的病原体多样性较低：在贝氏鹨的整个分布范围内，仅发现两种禽疟疾遗传谱系和一种禽痘谱系感染该物种。有趣的是，发现的两种禽疟疾寄生虫均为疟原虫属，此前在马卡罗尼西亚鸟类中未曾报道过（但在红脚隼Falco naumannii中观察到过），而禽痘是一个宿主特异性谱系，此前已在加那利群岛的两个岛屿上被报道过。
