Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA, USA.
Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA.
Malar J. 2018 Jan 8;17(1):12. doi: 10.1186/s12936-017-2165-5.
New World vultures (Cathartiformes: Cathartidae) are obligate scavengers comprised of seven species in five genera throughout the Americas. Of these, turkey vultures (Cathartes aura) and black vultures (Coragyps atratus) are the most widespread and, although ecologically similar, have evolved differences in morphology, physiology, and behaviour. Three species of haemosporidians have been reported in New World vultures to date: Haemoproteus catharti, Leucocytozoon toddi and Plasmodium elongatum, although few studies have investigated haemosporidian parasites in this important group of species. In this study, morphological and molecular methods were used to investigate the epidemiology and molecular biology of haemosporidian parasites of New World vultures in North America.
Blood and/or tissue samples were obtained from 162 turkey vultures and 95 black vultures in six states of the USA. Parasites were identified based on their morphology in blood smears, and sequences of the mitochondrial cytochrome b and nuclear adenylosuccinate lyase genes were obtained for molecular characterization.
No parasites were detected in black vultures, whereas 24% of turkey vultures across all sampling locations were positive for H. catharti by blood smear analysis and/or PCR testing. The phylogenetic analysis of cytochrome b gene sequences revealed that H. catharti is closely related to MYCAMH1, a yet unidentified haemosporidian from wood storks (Mycteria americana) in southeastern USA and northern Brazil. Haemoproteus catharti and MYCAMH1 represent a clade that is unmistakably separate from all other Haemoproteus spp., being most closely related to Haemocystidium spp. from reptiles and to Plasmodium spp. from birds and reptiles.
Haemoproteus catharti is a widely-distributed parasite of turkey vultures in North America that is evolutionarily distinct from other haemosporidian parasites. These results reveal that the genetic diversity and evolutionary relationships of avian haemosporidians are still being uncovered, and future studies combining a comprehensive evaluation of morphological and life cycle characteristics with the analysis of multiple nuclear and mitochondrial genes will be useful to redefine the genus boundaries of these parasites and to re-evaluate the relationships amongst haemosporidians of birds, reptiles and mammals.
新世界秃鹫（Cathartiformes：Cathartidae）是美洲五个属中七种专性食腐动物。在这些物种中，火鸡秃鹫（Cathartes aura）和黑秃鹫（Coragyps atratus）分布最广，尽管它们在生态上相似，但在形态、生理和行为上已经进化出了差异。迄今为止，已有三种血液原虫在新世界秃鹫中被报道：Haemoproteus catharti、Leucocytozoon toddi 和 Plasmodium elongatum，尽管很少有研究调查过这个重要物种群中的血液原虫寄生虫。在这项研究中，使用形态学和分子方法调查了北美的新世界秃鹫的血液原虫寄生虫的流行病学和分子生物学。
从美国六个州的 162 只火鸡秃鹫和 95 只黑秃鹫中获得血液和/或组织样本。寄生虫根据血液涂片的形态学进行鉴定，并获得线粒体细胞色素 b 和核腺嘌呤核苷琥珀酸裂解酶基因的序列进行分子特征分析。
黑秃鹫中未检测到寄生虫，而在所有采样地点，24%的火鸡秃鹫通过血液涂片分析和/或 PCR 检测呈 H. catharti 阳性。细胞色素 b 基因序列的系统发育分析表明，H. catharti 与 MYCAMH1 密切相关，后者是来自美国东南部和巴西北部的伍德鹳（Mycteria americana）的一种尚未鉴定的血液原虫。Haemoproteus catharti 和 MYCAMH1 代表一个与所有其他 Haemoproteus spp. 截然不同的分支，与来自爬行动物的 Haemocystidium spp. 和来自鸟类和爬行动物的 Plasmodium spp. 最为密切相关。
Haemoproteus catharti 是北美的火鸡秃鹫广泛分布的寄生虫，与其他血液原虫寄生虫在进化上不同。这些结果表明，鸟类血液原虫的遗传多样性和进化关系仍在被揭示，未来将结合对形态学和生命周期特征的全面评估以及对多个核和线粒体基因的分析的综合研究，将有助于重新定义这些寄生虫的属界，并重新评估鸟类、爬行动物和哺乳动物血液原虫之间的关系。
