University of Missouri-St. Louis, Department of Biology and Whitney R. Harris World Ecology Center, 1 University Blvd., St. Louis, MO 63121, USA.
Int J Parasitol. 2011 Aug 15;41(10):1019-27. doi: 10.1016/j.ijpara.2011.03.014. Epub 2011 Jun 1.
Haemosporidian parasites are widely distributed and common parasites of birds, and the application of molecular techniques has revealed remarkable diversity among their lineages. Four haemosporidian genera infect avian hosts (Plasmodium, Haemoproteus, Leucocytozoon and Fallisia), and Haemoproteus is split into two sub-genera based on morphological evidence and phylogenetic support for two divergent sister clades. One clade (Haemoproteus (Parahaemoproteus)) contains parasites developing in birds belonging to several different orders, except pigeons and doves (Columbiformes), while the other (Haemoproteus (Haemoproteus)) has previously been shown to only infect dove hosts. Here we provide molecular and morphological identification of Haemoproteus parasites from several seabird species that are closely related to those found in dove hosts. We also document a deeply divergent clade with two haemosporidian lineages recovered primarily from frigatebirds (Fregatidae, Pelecaniformes) that is sister to the hippoboscid-(Hippoboscidae) transmitted dove parasites. One of the lineages in this new clade of parasites belongs to Haemoproteus iwa and is distributed in two species of frigatebird (Fregata) hosts from Hawaii, the Galapagos Islands, the eastern Pacific and throughout the Caribbean Basin. Haemosporidian parasites are often considered rare in seabirds due in part to the lack or low activity of some dipteran vectors (e.g., mosquitos, biting midges) in marine and coastal environments; however, we show that H. iwa is prevalent and is very likely vectored among frigatebirds by hippoboscid flies which are abundant on frigatebirds and other seabirds. This study supports the existence of two sister clades of avian Haemoproteus in accord with the subgeneric classification of avian hemoproteids. Description of H. iwa from Galapagos Fregata minor is given based on morphology of blood stages and segments of the mitochondrial cytochrome b gene, which can be used for identification. This study shows that hippoboscid flies warrant more attention as vectors of avian Haemoproteus spp., particularly in marine and coastal environments.
血孢子虫广泛分布且常见于鸟类寄生虫，分子技术的应用揭示了其谱系中显著的多样性。四种血孢子虫属寄生虫感染鸟类宿主（疟原虫、疟原虫、白细胞原虫和法尔西亚），疟原虫根据形态证据和两个不同姐妹群的系统发育支持分为两个亚属。一个分支（疟原虫（副疟原虫））包含在除鸽子和鸽子（鸽形目）之外的几个不同目鸟类中发育的寄生虫，而另一个分支（疟原虫（疟原虫））以前仅感染鸽子宿主。在这里，我们提供了来自几种海鸟的疟原虫寄生虫的分子和形态鉴定，这些海鸟与鸽子宿主中的寄生虫密切相关。我们还记录了一个深度分化的分支，该分支有两个血孢子虫谱系主要从军舰鸟（军舰鸟科，鹈形目）中回收，与 hippoboscid-（ Hippoboscidae ）传播的鸽子寄生虫有亲缘关系。这个新寄生虫分支中的一个谱系属于疟原虫 iwa，分布在来自夏威夷、加拉帕戈斯群岛、东太平洋和整个加勒比海地区的两种军舰鸟（ Frigatebird ）宿主中。由于某些双翅目（如蚊子、吸血蠓）在海洋和沿海环境中缺乏或活性低，血孢子虫通常被认为在海鸟中很少见；然而，我们表明 H. iwa 很普遍，并且很可能通过 hippoboscid 蝇在军舰鸟和其他海鸟中传播，这些蝇在军舰鸟和其他海鸟中很丰富。这项研究支持鸟类疟原虫的两个姐妹群的存在，与鸟类血原虫的亚属分类一致。根据血液阶段和线粒体细胞色素 b 基因片段的形态描述了来自加拉帕戈斯群岛小军舰鸟的 H. iwa，可用于鉴定。这项研究表明， hippoboscid 蝇作为鸟类疟原虫 spp.的传播媒介值得更多关注，特别是在海洋和沿海环境中。
