Morphological and molecular characterisation of Sarcocystis capracanis, Sarcocystis cornagliai and Sarcocystis rossii n. sp. infecting the Alpine ibex (Capra ibex).
Eglė Rudaitytė-Lukošienė, Steffen Rehbein, Rafael Calero-Bernal, Dalius Butkauskas, Petras Prakas
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引用次数: 0
Abstract
Background: The cyst-forming coccidia of the genus Sarcocystis (Sarcocystidae) are widespread protists of mammals, particularly of domestic and wild ruminants. Research on genus Sarcocystis in wild members of the subfamily Caprinae is, however, rather limited. Sarcocystis in the Alpine ibex (Capra ibex) have only been investigated in depth once and then solely by morphological techniques. In the current investigation we aimed to morphologically and genetically characterise Sarcocystis species of Alpine ibex in Austria.
Methods: Sarcocysts detected in the diaphragm and myocardium muscles were morphologically described using light microscopy and transmission electron microscopy (TEM). Isolated sarcocysts were molecularly identified and characterised at the level of the 18S ribosomal RNA (rRNA) gene and cytochrome c oxidase I gene (cox1). The obtained sequences were subjected to phylogenetic analysis.
Results: Three Sarcocystis species, namely S. capracanis, S. cornagliai and S. rossii n. sp., were found in Alpine ibex. For the first time, we genetically characterised S. cornagliai, which is most closely related to Sarcocystis species that are transmitted by corvid birds. Sarcocysts of S. rossii n. sp. were found to be ribbon-shaped, with pointed tips. Hair-like protrusions about 5 μm in length were observed on sarcocyst walls. Observation of toluidine blue-stained semi-thin sections revealed that the sarcocyst of S. rossii n. sp. was thin-walled. Using TEM, cyst walls were observed to be similar to type 7a, with thin hair-like villar protrusions on the cyst wall, which were filled with many fine electron-dense granules. The ground substance layer was particularly thin, measuring 0.2-0.4 μm. The cox1 sequences of S. rossii n. sp. had the highest similarity to those of Sarcocystis arieticanis and Sarcocystis hircicanis. Sarcocystis rossii n. sp. had a close phylogenetic relationship with species that use canids as definitive hosts.
Conclusions: This study confirms the role of the Alpine ibex as an intermediate host of three Sarcocystis species and sets a new host record for S. capracanis. It also provides the first molecular data on Sarcocystis from Alpine ibex and on S. cornagliai. In addition, a new species, S. rossii, was identified and described. Phylogenetic analyses suggested corvid birds and canids as potential definitive hosts for S. cornagliai and S. rossii n. sp., respectively.
期刊介绍:
Parasites & Vectors is an open access, peer-reviewed online journal dealing with the biology of parasites, parasitic diseases, intermediate hosts, vectors and vector-borne pathogens. Manuscripts published in this journal will be available to all worldwide, with no barriers to access, immediately following acceptance. However, authors retain the copyright of their material and may use it, or distribute it, as they wish.
Manuscripts on all aspects of the basic and applied biology of parasites, intermediate hosts, vectors and vector-borne pathogens will be considered. In addition to the traditional and well-established areas of science in these fields, we also aim to provide a vehicle for publication of the rapidly developing resources and technology in parasite, intermediate host and vector genomics and their impacts on biological research. We are able to publish large datasets and extensive results, frequently associated with genomic and post-genomic technologies, which are not readily accommodated in traditional journals. Manuscripts addressing broader issues, for example economics, social sciences and global climate change in relation to parasites, vectors and disease control, are also welcomed.