Sarcocystis sp. from the goldeneye (Bucephala clangula) and the mallard (Anas platyrhynchos): cyst morphology and ribosomal DNA analysis

Abstract

By light microscopy, cysts of Sarcocystis sp. (cyst type I) from the goldeneye (Bucephala clangula) seemed filamentous with a smooth and thin (<1 microm) cyst wall. Ultrastructurally, the cyst wall surface was irregular with minute undulations of the primary cyst wall. These sarcocysts had type-1 cyst wall. Cystozoites were banana-shaped and measured 7.0-8.5 microm in length. By light microscopy, cysts of Sarcocystis sp. (cyst type II) from the mallard (Anas platyrhynchos) were ribbon-shaped, very long, and thin. On the surface of the wall (up to 1.5 microm), they had palisade-like villar protrusions closely crowded together. Electron micrographs showed villar protrusions (up to 1.3 microm in length) different in size and shape. The latter had short microprojections especially obvious in the oblique sections. Cystozoites were slightly bent with blunt ends, broader at one end, and measured 13.0-16.1 x 1.8-2.5 microm. Phylogenetic analysis based on the comparison of partial 28S rRNR gene sequences of Sarcocystis sp. (cyst type II) derived from the mallard, Sarcocystis sp. (cyst type I) and Sarcocystis sp. (cyst type III) both derived from the white-fronted goose (Anser albifrons) suggested that these sequences belonged to separate Sarcocystis species.

The mallard duck (Anas platyrhynchos) as intermediate host for Sarcocystis wobeseri sp. nov. from the barnacle goose (Branta leucopsis)

“…However, as the earlier data and those presented in this article showed, the results of TEM can be at variance with the results of light microscopy. For example, Sarcocystis cyst walls of the common goldeneye (Bucephala clangula; Kutkienė et al 2008) and the barnacle goose, which seemed to be smooth by light microscopy (according to our classification cyst type I), were clearly wavy by TEM. The case might be that only one cyst type, which has a thin wall with a characteristic wavy surface and many invaginations of the primary cyst wall (according to the classification of Dubey and Odening (2001)-cyst wall type-1) is found in the birds order Anseriformes.…”

“…As has already been noted earlier, the wall type-1 (Dubey and Odening 2001) has been determined for sarcocysts from the lesser snow and Canada geese ) and from the goldeneye (Kutkienė et al 2008). An undulating cyst wall was seen in the white-rumped swift and the night heron from South Africa (Kaiser and Markus 1983).…”

“…Cyst wall ultrastructure of other anseriforms, i.e., of S. rileyi (Dubey et al 2003), Sarcocystis sp. (cyst type II) from the mallard (Kutkienė et al 2008), Sarcocystis sp. (cyst type III) from the white-fronted goose (Kutkienė et al 2006) and sarcocysts (with finger-like protrusions on the cyst wall surface) from lesser snow and Ross geese ) differed greatly from morphology of Sarcocystis isolates presented in this paper.…”

“…Since the same types of cysts were found in different species of birds order Anseriformes, the hypothesis was put forward that the same species of Sarcocystis could parasitize different species of birds order Anseriformes. Later investigations into the ultrastructure of the cyst walls of some bird species and DNA analysis were undertaken (Kutkienė et al 2006;Kutkienė et al 2008).…”

“…Kutkienė and Sruoga (2004) present similar data. They discovered four types of microcysts in ducks: two of them had a smooth or wavy cyst wall that is difficult to distinguish by light microscopy and other two had protrusions of different length and shape on the wall surface (Kutkienė et al 2008).…”