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

Abstract

The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smooth and without microtubules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was up to 4.0 μm. The vp were up to 3.0 μm long and most closely resembled "type 9c." All sarcocysts were mature and contained numerous 8.1 × 2.1 μm sized bradyzoites. Molecular characterization (at 18S rDNA, 28S rDNA, ITS-1, and cox1) showed the highest affinity for S. arctica of the Arctic fox (V. lagopus) from Norway. In the present investigation, we provide evidence that sarcocysts are common in tongues of Alaskan Arctic foxes suggesting that these carnivores are serving as intermediate hosts, and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.

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 ].…”

Genetic diversity of vector-borne pathogens in spotted and brown hyenas from Namibia and Tanzania relates to ecological conditions rather than host taxonomy

“…Carnivores are often definitive hosts of Sarcocystis spp. but a few species also use carnivores as intermediate hosts, such as Sarcocystis caninum and Sarcocystis svanai in domestic dogs and Sarcocystis arctica in arctic foxes ( Vulpes lagopus ) and red foxes [ 94 – 98 ]. Since the life cycle includes stages that infect mononuclear cells, finding Sarcocystis spp.…”

Role of three bird species in the life cycle of two Sarcocystis spp. (Apicomplexa, Sarcocystidae) in the Czech Republic

“…arctica in the white-tailed sea eagle might represent the first report of its definitive host and the first morphological and molecular characterization of these developmental stages. Sarcocystis arctica was originally described from the arctic fox in Norway ( Gjerde and Schulze, 2014 ) and later in the same host from Alaska, USA (see Cerqueira-Cézar et al, 2017 ), in the wolf Canis lupus Linnaeus, 1758 from Alaska, USA ( Calero-Bernal et al, 2016 ), in V . vulpes from the Czech Republic (see Pavlásek and Máca, 2017 ), Latvia, Lithuania and Spain (see Kirillova et al, 2018 ), as well as in corvid birds from Lithuania ( Juozaityté-Ngugu et al, 2021 ).…”