The morphology of cysts of Sarcocystis infecting birds in western Canada

Abstract

A light microscope study of the cyst wall of some avian Sarcocystis spp. was undertaken to determine if there were morphological differences in cysts found in different bird species. The cyst wall of macrocysts was different in young and old ducks. Five kinds of microcysts were described from birds, two having smooth outer walls, and three having radial spines on their outer surface. Cysts were differentiated on the basis of the thickness of the outer wall, and on the length and proximity of the radial spines to each other. Specific cyst types were found in several different bird species, and given bird species may harbor more than one cyst type, sometimes concurrently. It is hypothesized that the different cyst types represent different species of Sarcocystis.

Sarcocystis sp. from white-fronted goose (Anser albifrons): cyst morphology and life cycle studies

“…Publications of this nature are not abundant in Europe and Asia (Pak and Eshtokina 1984;Kalisińska et al 2003;Kutkienė and Sruoga 2004). Though several types of Sarcocystis cysts have been recorded in ducks (Drouin and Mahrt 1980;Kutkienė and Sruoga 2004), only one species-Sarcocystis rileyi-whose definitive host is a skunk in North America, has been described at length (Dubey et al 2003). According to the morphological features, this species is found in Europe too (Kutkienė and Sruoga 2004); however, its definitive host is unknown on this continent.…”

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

“…In most cases, sarcocycts found in the mallard are described as S. rileyi; however, in this host in Canada, Drouin and Mahrt (1980) also found microcysts of two wall surface types of which (1.5 to 2.0 μm) the following was detected under a light microscope: (1) radial spines closely crowded together and (2) radial spines widely spaced. It is possible that one type of these cysts corresponds to our type (cyst type II) from the mallard.…”

“…As was shown in our earlier (Kutkienė and Sruoga 2004) and recent investigations, sarcocysts of this type (having a smooth and thin cyst wall and small cystozoites by light microscopy) were found in ten (including the wigeon) further species of anseriform bird. Sarcocystis microcysts with a smooth wall were also found in four species of duck in Canada (Drouin and Mahrt 1980). However, unfortunately, investigations carried out by us and other authors by light microscopy only do not allow us to make a detailed comparison of the peculiarities of the cyst morphology of these protists.…”

“…In many cases, macroscopic sarcocysts of a rice grain size, which have been described as S. rileyi, were found in ducks. However, further species of Sarcocystis found in these birds have not been sufficiently studied and remain unnamed (Drouin and Mahrt 1980;Kutkienė and Sruoga 2004). It is difficult to judge about the prevalence of these parasites and their species composition in wild ducks in Europe because there are only a few publications available about this issue: sarcocysts were found in Bulgaria, Poland, and Lithuania (Kalyakin and Zasukhin 1975;Kalisińska et al 2003;Kutkienė and Sruoga 2004).…”

Morphologic characterization of Sarcocystis sp. sarcocysts from the Buffon’s macaw (Ara ambigua)

“…The sarcocyst wall in S. rileyi corresponds to type 21, characterized by cauliflower-like anastomosing villar protrusions (Dubey et al 1989(Dubey et al , 2003. By contrast, the sarcocyst wall in S. falcatula is thick, striated, with finger-like villar protrusions (Drouin and Mahrt 1980;Box et al 1984;Dubey et al 2000Dubey et al , 2001aLuznar et al 2001). The sarcocysts of S. ramphastosi are macroscopic and divided into two distinct zones, whereas the species in the macaw is microscopic.…”