Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus)

Abstract

Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in the muscles of a gray wolf (Canis lupus) from Alaska, USA, for the first time. Sarcocysts extracted from the tongue of the wolf were up to 900 μm long and slender and appeared to have a relatively thin wall by light microscope. By transmission electron microscopy, the sarcocyst wall most closely resembled "type 9c," and had a wavy parasitophorous vacuolar membrane folded as pleomorphic villar protrusions (vp), with anastomoses of tips. The vp and the ground substance (gs) layer were smooth without tubules or granules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was 3.5 μm. The vp were up to 1.5 μm long. Mature sarcocysts contained numerous bradyzoites and few metrocytes. The bradyzoites were 9.5 μm long and 1.5 μm wide, and contained all organelles found in Sarcocystis bradyzoites with at least two rhoptries. Molecular characterization showed the highest identity for 18S rRNA, 28S rRNA, ITS-1, and cox1 sequences of Sarcocystis arctica of the Arctic fox (Vulpes lagopus) from Norway. The ultrastructure of S. arctica from the fox is unknown. Here, we provide ultrastructure of S. arctica from the Alaskan wolf for the first time. The definitive host of S. arctica remains unknown.

Identification and genetic characterization of Sarcocystis arctica and Sarcocystis lutrae in red foxes (Vulpes vulpes) from Baltic States and Spain

“…3a , b ). Sarcocystis arctica detected in the red fox here presents similar ultrastructure as previously described in the Alaskan wolf and Arctic fox [ 26 , 27 ] in North America. In addition, S. lutrae sarcocysts from red foxes are morphologically similar to those of other Sarcocystis species detected in carnivores, e.g.…”

“…arctica is characterized by some intraspecific variability within 28S rDNA, ITS1, cox 1 and rpoB . The clearly distinguished S. arctica haplotypes A and B at cox 1 were identified for Norwegian isolates of the Arctic fox, and for Latvian/Lithuanian and Czech isolates from the red fox, whereas Alaskan isolates from two intermediate hosts, the grey wolf and Arctic fox, were only haplotype A, and S. arctica from the Spanish red fox had haplotype B ([ 5 , 13 , 26 , 27 ] and present study). At rpoB , two SNPs were determined between haplotype 1 and 3, and only one SNP between haplotype 1 and 2, and between haplotype 3 and 4 (Fig.…”

“…from the Japanese red fox [ 9 ] is similar to S. lutrae . Recently, the Arctic fox and the Alaskan wolf were identified as being an intermediate host of S. arctica [ 5 , 26 , 27 ]. Moreover, based on cox 1 comparison it was shown that one Arctic fox from Norway acted as the intermediate host for two Sarcocystis species, S. arctica and S. lutrae [ 6 ].…”

Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus) from Alaska, USA

“…This shared 99.3% similarity with S. lutrae from Norwegian Eurasian otters (KF601326) (Gjerde and Josefsen 2015) and 98.9% similarity with S. turdusi (KT588518) (Prakas et al unpublished). Our phylogenetic study denotes that S. arctica from Alaskan wolf (Calero-Bernal et al 2016), S. arctica from Norwegian Arctic foxes (Gjerde and Schulze 2014) and Sarcocystis from Alaskan Arctic foxes (present study) are in the same clade. That conclusion is supported here as neighbor-joining 18S rDNA and cox1 trees show greater than 99% bootstrap support for a clade encompassing all S. arctica sequences, including the sequences derived from sarcocysts present in Arctic fox tongues presented here.…”

“…The remaining species agreed with previous analyses (Gjerde and Schulze 2014) and are shown for consistency with past analyses. Bootstrap values are only shown for those partitions that appeared in greater than 85% of replicates wolf (KX022112; KX022113; KX022114; KX022115) (Calero-Bernal et al 2016) and Norwegian Arctic fox (KF601319) (Gjerde and Schulze 2014). This shared 99.3% similarity with S. lutrae from Norwegian Eurasian otters (KF601326) (Gjerde and Josefsen 2015) and 98.9% similarity with S. turdusi (KT588518) (Prakas et al unpublished).…”