Morphological and molecular identification of Sarcocystis arctica sarcocysts in three red foxes (Vulpes vulpes) from the Czech Republic

Identification of Sarcocystis and Trichinella Species in Muscles of Gray Wolf (Canis lupus) from Lithuania

Apicomplexan Sarcocystis and Trichinella nematodes are food-borne parasites whose life cycle is carried-out in various wildlife and domestic animals. The gray wolf (Canis lupus) is an apex predator acting as an ecosystem engineer. This study aimed to identify the species of Sarcocystis and Trichinella found in the muscles of gray wolves in Lithuania. During the 2017-2022 period, diaphragm, heart, and hind leg samples of 15 animals were examined. Microscopical analysis showed the presence of two types of Sarcocystis parasites in 26.7% of the analyzed muscle samples. Based on the sequencing of five loci, nuclear 18S rDNA, 28S rDNA, ITS1, mitochondrial cox1, and apicoplast rpoB, S. arctica, and S. svanai were identified. The current work presents the first report of S. svanai in gray wolf. Phylogenetically, S. svanai clustered together with S. lutrae, infecting various carnivorans, and S. arctica was most closely related to S. felis from domestic cats. Trichinella spp. were found in 12 gray wolves (80%). For the first time, Trichinella species were molecularly identified in gray wolves from Lithuania. Trichinella britovi was confirmed in all of the isolated Trichinella larvae using a multiplex PCR. Gray wolves in Lithuania may serve as a major source of zoonotic pathogens due to the presence of these parasites.

Fatal hepatic sarcocystosis in three captive and one free-ranging pinniped

Fatal hepatic sarcocystosis was diagnosed as the cause of death in four pinnipeds: two captive Hawaiian monk seals (Monachus schauinslandi), a captive, and a free-ranging California sea lion (Zalophus californianus). Based on necropsy, histopathology, electron microscopy and DNA sequencing, intralesional protozoal schizonts were determined to have caused the necrotizing hepatitis observed. Transmission Electron Microscopy (TEM) revealed schizonts similar to Sarcocystis canis in hepatocytes. PCR-DNA sequencing and phylogenetic analysis at the conserved 18S rRNA and variable ITS1 gene markers within the nuclear rRNA gene array from schizont-laden tissue established that the parasites were indistinguishable from Sarcocystis canis at the 18S rRNA locus. However, six distinct single nucleotide polymorphisms (SNPs) were resolved at ITS1 suggesting that the parasites infecting pinnipeds were distinct from S. canis, which commonly infects bears and dogs. We hypothesize that the parasite represents a novel Sarcocystis variant that we refer to as S. canis-like that infects pinnipeds. The definitive host of S. canis is enigmatic and its life cycle incomplete. These findings document a critical need to identify the life cycle(s), definitive host(s), and all susceptible marine and terrestrial intermediate hosts of S. canis and the S. canis-like variant infecting pinnipeds.

Meningoencephalitis caused by concurrent infection with canine distemper virus and a unique Sarcocystis sp. in a gray fox

A deceased 9-wk-old male gray fox (Urocyon cinereoargenteus) with a history of decreased ambulation and diarrhea was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory. No significant gross findings were evident on postmortem examination. Histologically, the cerebrum and brainstem had mild necrotizing meningoencephalitis with protozoal schizonts and merozoites. Additionally, glial cells contained intracytoplasmic and intranuclear viral inclusion bodies. Sections of the cerebrum were positive for canine distemper virus (CDV) and negative for Sarcocystis neurona on immunohistochemistry. Bayesian analysis revealed that this Sarcocystis sp. clustered most closely with a clade of unnamed Sarcocystis sp. found in viperid snakes, with a posterior probability of 99%. CDV likely played a significant role in the expression of clinical sarcocystosis in this gray fox.

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

Birds are one of the groups involved in the development of Sarcocystis Lankester (1882), serving either as intermediate or definitive hosts. The white-tailed sea eagle Haliaeetus albicilla (Linnaeus, 1758), red kite Milvus milvus (Linnaeus, 1758) (both Accipitriformes) and common starlings Sturnus vulgaris Linnaeus, 1758 (Passeriformes) were examined to elucidate their participation in the development of Sarcocystis, as well as to determine the specific identity of the parasites based on morphological and especially molecular analyses. In 2020-2021, one white-tailed eagle, one red kite and five common starlings were parasitologically examined for the presence of Sarcocystis using flotation centrifugation coprological method and by wet mounts of intestinal mucosa scrapings and/or muscle samples. Positive samples were processed by light microscopy, histologically and followed molecularly at four genetic markers (18S rRNA, 28S rRNA, ITS1 and cox1). The white-tailed eagle harboured oocysts/sporocysts of S. arctica Gjerde et Schulze, 2014 in the intestinal mucosa, while the intestinal mucosa of the red kite and breasts and leg muscles of one common starling were positive to S. halieti Gjerde, Vikøren et Hamnes, 2018. Sequences from eagle shared 99.6-100% identity with each other and S. arctica in the red fox (V. vulpes Linnaeus, 1758) from the Czech Republic. Sequences from the common starling and red kite shared 100% identity with each other and with S. halieti in the great cormorant (P. carbo [Linnaeus, 1758]) from Lithuania and H. albicilla from Norway. The white-tailed sea eagle might act as definitive host of S. arctica, whereas the common starling and red kite represent intermediate and potential definitive hosts, respectively, for S. halieti.

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

Background

Improved knowledge on vector-borne pathogens in wildlife will help determine their effect on host species at the population and individual level and whether these are affected by anthropogenic factors such as global climate change and landscape changes. Here, samples from brown hyenas (Parahyaena brunnea) from Namibia (BHNA) and spotted hyenas (Crocuta crocuta) from Namibia (SHNA) and Tanzania (SHTZ) were screened for vector-borne pathogens to assess the frequency and genetic diversity of pathogens and the effect of ecological conditions and host taxonomy on this diversity.

Methods

Tissue samples from BHNA (n = 17), SHNA (n = 19) and SHTZ (n = 25) were analysed by PCRs targeting Anaplasmataceae, Rickettsia spp., piroplasms, specifically Babesia lengau-like piroplasms, Hepatozoidae and filarioids. After sequencing, maximum-likelihood phylogenetic analyses were conducted.

Results

The relative frequency of Anaplasmataceae was significantly higher in BHNA (82.4%) and SHNA (100.0%) than in SHTZ (32.0%). Only Anaplasma phagocytophilum/platys-like and Anaplasma bovis-like sequences were detected. Rickettsia raoultii was found in one BHNA and three SHTZ. This is the first report of R. raoultii from sub-Saharan Africa. Babesia lengau-like piroplasms were found in 70.6% of BHNA, 88.9% of SHNA and 32.0% of SHTZ, showing higher sequence diversity than B. lengau from South African cheetahs (Acinonyx jubatus). In one SHTZ, a Babesia vogeli-like sequence was identified. Hepatozoon felis-like parasites were identified in 64.7% of BHNA, 36.8% of SHNA and 44.0% of SHTZ. Phylogenetic analysis placed the sequences outside the major H. felis cluster originating from wild and domestic felids. Filarioids were detected in 47.1% of BHNA, 47.4% of SHNA and 36.0% of SHTZ. Phylogenetic analysis revealed high genetic diversity and suggested the presence of several undescribed species. Co-infections were frequently detected in SHNA and BHNA (BHNA median 3 pathogens, range 1–4; SHNA median 3 pathogens, range 2–4) and significantly rarer in SHTZ (median 1, range 0–4, 9 individuals uninfected).

Conclusions

The frequencies of all pathogens groups were high, and except for Rickettsia, multiple species and genotypes were identified for each pathogen group. Ecological conditions explained pathogen identity and diversity better than host taxonomy.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04835-x.

Molecular identification of Sarcocystis lutrae (Apicomplexa: Sarcocystidae) from the raccoon dog, Nyctereutes procyonoides, and the common raccoon, Procyon lotor, in the Czech Republic

Background

Apicomplexan parasites of the genus Sarcocystis have an obligate two-host life-cycle and comprise about 200 species, which infect different cold- and warm-blooded hosts, including humans. Recently, morphological and molecular studies of sarcocysts in broadly spread carnivore hosts have been on the rise. The description of muscular tissues infection by Sarcocystis in the raccoon dog and the common raccoon from the Czech Republic is herein presented.

Methods

During January-August 2019, 15 raccoon dogs and 1 common raccoon were examined from 5 districts (Česká Lípa, Liberec, Mladá Boleslav, Trutnov and Ústí nad Labem) of the Czech Republic. Muscle parts (diaphragm, forearm, hind-limb, tongue and heart) were examined in wet preparations under compression by light microscopy. After finding Sarcocystis sp., morphological characteristics and molecular analyses of 18S rRNA, 28S rRNA, ITS1 and cox1 loci were used to identify the species.

Results

Sarcocysts were detected and identified in 1 out of 15 raccoon dogs and in the single common raccoon. Preferential infection sites were diaphragm and tongue, followed by forearm and hind limb. To our knowledge, this is the first identification of microscopic sarcocysts by multi-locus genetic analysis from both host species. Molecular analyses revealed 100% similarity at 18S rRNA, 28S rRNA, and cox1 genes with S. lutrae for both hosts and 98–100% identity at the ITS1 region of the isolate from the common raccoon.

Conclusions

Both widely distributed non-indigenous wild carnivores represent new intermediate host records for S. lutrae and the first report of this parasite in a member of the family Procyonidae, but still with an unknown natural definitive host. Molecular data revealed that this parasite species appears more closely related to the Sarcocystis spp. using raptorial birds as definitive hosts. Therefore, further studies aimed at its identification, including the complete life-cycle, remain necessary.

First isolation of Sarcocystis caninum sarcocysts from two domestic dogs (Canis familiaris) from China

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.

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

Background

Typically, carnivores serve as definitive hosts for Sarcocystis spp. parasites; currently, their role as intermediate hosts is being elucidated. The present study aimed to identify and molecularly characterize Sarcocystis cysts detected in striated muscle of red foxes from different populations in Latvia, Lithuania and Spain.

Methods

Muscle samples from 411 red foxes (Vulpes vulpes) and 269 racoon dogs (Nyctereutes procyonoides) from Latvia, 41 red foxes from Lithuania and 22 red foxes from Spain were examined for the presence of Sarcocystis sarcocysts by light microscopy (LM). Sarcocystis spp. were identified by transmission electron microscopy (TEM) and molecular biology techniques.

Results

Sarcocystis cysts were detected in 11/411 (2.7%) Latvian, 3/41 (7.3%) Lithuanian, and 6/22 (27.3%) Spanish red foxes, however, cysts were not observed in the muscles of racoon dogs. Based on LM, TEM, 18S rDNA, 28S rDNA, ITS1, cox1 and rpoB sequences, Sarcocystis arctica and Sarcocystis lutrae cysts were identified in red fox muscles from Latvia and Lithuania, whereas only S. arctica was detected in Spain. The 18S rDNA, 28S rDNA and ITS1 sequences from the 21 isolates of S. arctica from Latvia, Lithuania and Spain were identical. By contrast, two and four haplotypes were determined based on mtDNA cox1 and apicoplast rpoB sequences, respectively. Polymorphisms were not detected between the two isolates of S. lutrae from Latvia and Lithuania. Based on phylogenetic results, S. arctica and S. lutrae were most closely related to Sarcocystis spp. using predatory mammals as intermediate hosts and to Sarcocystis species with a bird-bird life-cycle.

Conclusions

Based on current knowledge, the red fox and Arctic fox (Vulpes lagopus) could act as intermediate host for the same two Sarcocystis species. Molecular results suggest the existence of two genetic lineages of S. arctica, and such divergence relies on its geographical distribution but not on their intermediate host species.

Molecular identification of Sarcocystis lutrae in the European otter (Lutra lutra) and the European badger (Meles meles) from the Czech Republic

Muscular sarcosporidial infections by Sarcocystis lutrae (Apicomplexa: Sarcocystidae) from the otter (Lutra lutra) and badger (Meles meles) (Carnivora: Mustelidae) were found in the Czech Republic. As part of a diversity evaluation of Sarcocystis in wild carnivores during 2016-2017, samples of diaphragm, tongue and hind-limb muscles were collected from nine districts, examined by compression and characterized molecularly. Cyst walls were thin, with no visible protrusions, and histological sections of infected muscle tissue showed no host responses. Fourteen of 17 badgers (82% prevalence) and one otter (100% prevalence) were positive for sarcocysts. Sequence analyses at four loci (18S rRNA, 28S rRNA, ITS1 and cox1) confirmed the identity as S. lutrae. This is also the first report of a co-infection with muscular sarcocystosis and Trichinella in badger. The finding of Trichinella is important from the zoonotic point of view, since badgers are used for meat consumption. Similar and future monitoring of both parasitic taxa are needed.