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The presence of Sarcocystis cysts in the muscle tissue of domestic dogs (Canis familiaris), which normally serve as definitive hosts, is unusual and infrequent. Here, S. caninum sarcocysts were identified for the first time in two of 37 dogs (2.7%) from China. Examination using light microscopy found that the S. caninum sarcocysts were up to 1520 μm long and up to 147 μm wide and contained numerous 1.5-3.3 μm wedge-like villar protrusions (vp). Transmission electron microscopy revealed that the sarcocysts had pleomorphic vp that closely resembled those of “type 9c.” Five loci, 18S rDNA, 28S rDNA, mitochondrial cox1, ITS1 and ropB, were sequenced and characterized in S. caninum sarcocysts. The sequences of the five loci shared similarities of 99.9-100%, 99.0-100%, 99.4-100%, 99.6-100%, and 99.7-100%, respectively, with those of S. arctica. Phylogenetic analysis based on the sequences of 28S rDNA and mitochondrial cox1 indicated that S. caninum and S. arctica are closely related to Sarcocystis species that use a raptorial bird as their definitive host. [ABSTRACT FROM AUTHOR]

Water buffalo ( Bubalus bubalis) is the intermediate host for at least four species of Sarcocystis: S. fusiformis, S. buffalonis, S. levinei, and S. sinensis/ S. dubeyi. Here, a new species, Sarcocystis dehongensis, is reported in 51 of 756 (6.7%) water buffaloes in China. By light microscopy, the cysts of S. dehongensis were macroscopic, up to 18.5 mm long and 95 μm in diameter; 4.9-11.9 μm villous protrusions extended beyond the sarcocyst wall. Using transmission electron microscopy, the sarcocyst wall had lancet- or leaf-like protrusions in longitudinal section, but the cross section showed that the protrusions appeared as mushroom-like in shape with a core of tightly packed microtubules, similar to 'type 24.' BLAST searches revealed that S. dehongensis shared the most similarities with the 18S rDNA sequence of S. hardangeri (92.4%) and mitochondrial cox1 gene sequence of S. ovalis (81.0%), whereas no sequences in GenBank were found to be significantly similar to the ITS-1 region of S. dehongensis. A phylogenetic analysis based on 18S rDNA and mitochondrial cox1 gene sequences suggested that S. dehongensis was closely related to Sarcocystis species from cervids that employ corvids as definitive hosts. [ABSTRACT FROM AUTHOR]

There is considerable confusion concerning the relationships among species of Sarcocystis found in donkeys and horses. Here, we describe a Sarcocystis species in Chinese donkeys (Equus asinus). Sarcocysts were found in 12 of 32 (37.5%) adult donkeys. By light microscopy, they were divided into two types, thin-walled and thick-walled. The thin-walled were macroscopic (up to 320 μm wide) and had short club-like protrusions (up to 2.7 μm long); the thick-walled were microscopic (up to 135 μm wide) and had villar protrusions (up to 5.4 μm long). Ultrastructures of the two types exhibited similar morphological characteristics, including bundled microtubules in the core of the villar protrusions penetrating diagonally into the ground substance, similar to wall type 11c. Three genetic markers, 18S rDNA, 28S rDNA, and mitochondrial cox1, obtained from the two morphotypes were sequenced and analyzed. The sequences of the three loci in the two morphotypes presented high intraspecific similarities of 97.2–99.5%, 97.8–99.6% and 99.0 − 99.9%, respectively. The most similar sequences in GenBank to the newly obtained 18S rDNA, 28S rDNA and cox1 sequences were those of Sarcocystis spp. in horses, with similarities of 90.0 − 97.5%, 94.7 − 95.1%, and 82.6 − 84.5%, respectively. Phylogenetic analysis using the three genetic markers indicated that the Sarcocystis sp. in donkeys formed an individual clade most closely related to a clade encompassing Sarcocystis spp. in horses. Further studies are needed for taxonomic identification of sarcocysts in donkeys because the Sarcocystis species in donkeys and horses are not successfully cross transmissible despite morphological similarities. [ABSTRACT FROM AUTHOR]

In the present study, sarcocysts of Sarcocystis cymruensis were found in four of 42 (9.5%) Norway rats and those of S. ratti were observed in six of 60 (10%) black rats in China. With light microscopy, the sarcocysts of the two parasites were microscopic, and had smooth, thin cyst walls (≤ 1 μm). Ultrastructurally, the sarcocysts of S. cymruensis had small, osmiophilic, bleb-like protrusions, similar to type 1c; those of S. ratti had a cyst wall with regular, short, conical protrusions, similar to type 1 g. Three loci, i.e., 18S rDNA, the mitochondrial cox1 gene (Cox1), and the mitochondrial Cytb gene (Cytb), of the two parasites were sequenced and analyzed, and the Cytb sequences of the two parasites constituted the first records of this marker in GenBank. A comparison of the newly obtained sequences of the three loci between the two parasites revealed that the interspecific similarities of 18S rDNA, Cox1, and Cytb were 96.4–97.2%, 96.5%, and 93.7%, respectively. Therefore, the two species could be better discriminated with Cytb than with 18S rDNA and Cox1. Phylogenetic analysis based on 18S rDNA sequences and Cox1 sequences indicated that the two parasites had a close relationship with Sarcocystis in nonruminant animals, especially birds and canids. [ABSTRACT FROM AUTHOR]

In this study, 36.8% (28/76) of tissue samples collected from domestic pigs (Sus scrofa) contained sarcocysts, as determined by light microscopy. The organisms were identified as Sarcocystis miescheriana and Sarcocystis suihominis based on their morphological and molecular characteristics. Four genetic markers, i.e., 18S rDNA, 28S rDNA, ITS-1 region (ITS-1), and the mitochondrial COX1 gene (COX1), of the two parasites were sequenced and analyzed, and the 28S rDNA and ITS-1 of S. suihominis obtained from pigs constituted the first records of these markers in GenBank. The sequences of the four loci (18S rDNA, 28S rDNA, ITS-1, and COX1) of S. miescheriana shared high identities with those of S. miescheriana obtained from domestic and/or wild pigs in GenBank, with similarities of 99.6%, 99.6%, 95.9%, and 95.4%, respectively. The 18S rDNA sequences of S. suihominis exhibited 99.4% identity with those of S. suihominis from domestic and wild pigs. The comparison of the newly obtained sequences of the four genetic markers between the two parasites revealed that the interspecific similarities of 18S rDNA, 28S rDNA, ITS-1, and COX1 were 97.7%, 96.6%, 80.3%, and 81.2%, respectively. Therefore, the two species could be better discriminated with ITS-1 and mitochondrial COX1 compared with 18S rDNA or 28S rDNA. The phylogenetic analysis using 28S rDNA indicated that the two Sarcocystis species in domestic pigs had a close relationship. [ABSTRACT FROM AUTHOR]

In our previous study, we obtained a large number of differentially expressed genes (DEGs) between second-generation merozoites (MZ-2) and third-generation merozoites (MZ-3) of Eimeria necatrix using RNA sequencing (RNA-seq). Here, we report two subtractive cDNA libraries for MZ2 (forward library) and MZ3 (reverse library) that were constructed using suppression subtractive hybridization (SSH). PCR amplification revealed that the MZ2 and MZ3 libraries contained approximately 96.7% and 95% recombinant clones, respectively, and the length of the inserted fragments ranged from 0.5 to 1.5 kb. A total of 106 and 111 unique sequences were obtained from the MZ2 and MZ3 libraries, respectively, and were assembled into 13 specific consensus sequences (contigs or genes) (5 from MZ2 and 8 from MZ3). The qRT-PCR results revealed that 11 out of 13 genes were differentially expressed between MZ-2 and MZ-3. Of 13 genes, 11 genes were found in both SSH and our RNA-seq data and displayed a similar expression trend between SSH and RNA-seq data, and the remaining 2 genes have not been reported in both E. necatrix genome and our RNA-seq data. Among the 11 genes, the expression trends of 8 genes were highly consistent between SSH and our RNA-seq data. These DEGs may provide specialized functions related to the life-cycle transitions of Eimeria species. [ABSTRACT FROM AUTHOR]