Phylogenetic relationships between Sarcocystis species from reindeer and other Sarcocystidae deduced from ssu rRNA gene sequences

Toxoplasma gondii and related Sarcocystidae parasites in harvested caribou from Nunavik, Canada

Caribou are keystone species important for human harvest and of conservation concern; even so, much is unknown about the impact of parasites on caribou health and ecology. The aim of this study was to determine the seroprevalence, tissue prevalence, and diversity of tissue-dwelling coccidian parasites (including Toxoplasma gondii, Neospora caninum and Sarcocystis spp.) in 88 migratory caribou (Rangifer tarandus) harvested for human consumption in two communities in Nunavik, Québec, Canada. Both T. gondii and N. caninum have potential to cause abortions and neurological disease in caribou. Seroprevalence for antibodies to T. gondii using ELISA on fluid from thawed hearts was 18% overall, and no DNA of T. gondii was detected in tissues, which has positive implications for food safety since this parasite is zoonotic. Seroprevalence for antibodies to N. caninum using competitive ELISA was 5%, and DNA of N. caninum was detected in only one heart sample. DNA of Sarcocystis, a non-zoonotic, related coccidian, was detected in tissue samples from 85% of caribou, with higher prevalence in heart (82%) than skeletal muscle (47%). This is the first time that Sarcocystis spp. from caribou in Canada have been identified to species level, many of which have been described in reindeer from Fennoscandia. The high prevalence and diversity of Sarcocystis spp. suggests intact trophic relationships between canids and caribou in Nunavik. Besnoitia spp. was serendipitously detected in three muscle samples, a parasite previously associated with skin lesions in caribou in Nunavik. Community-level differences in T. gondii exposure and prevalence of Sarcocystis spp. in skeletal muscle tissues may reflect differences in hunter selection of individual animals and muscles, or possibly regional differences in the ecology of carnivore definitive hosts for these parasites. Further work is needed to explore effects of tissue coccidians in caribou, their taxonomic classifications, and community level differences in parasite prevalence and diversity.

Identification of a new Sarcocystis sp. in marsh deer (Blastocerus dichotomus) from wetlands of Argentina

The marsh deer (Blastocerus dichotomus) is the largest South American native deer species and is listed as "Vulnerable" by IUCN due to the population reduction. As part of a conservation and disease surveillance program, muscle samples from 14 marsh deer found dead in 2016 and 2017 in northeast Argentina were obtained at necropsy. Samples from each animal were processed as pooled muscles (heart, diaphragm, tongue and hindlimb) by homogenization and direct microscopical observation to detect intracellular Sarcocystis spp. cysts. Sarcocysts were observed in six samples, and several cysts recovered from two samples were processed by transmission electron microscopy. The cysts were thin-walled and showed a cyst-wall ultrastructure with ribbon-like protrusions similar to other species using cervids as intermediate host and canids as definitive hosts. Genomic DNA from individual sarcocysts from three marsh deer were successfully amplified by PCR of 18S rRNA and COI gene fragments and further sequenced. Sequence comparison revealed a 99.3-100% identity among them and only 93.7-96.6% and 88.8-89.7% identity at 18S rRNA and COI markers, respectively, with other Sarcocystis spp. Despite morphological similarities, the high sequence divergence at 18S rRNA and COI fragments allowed the assumption that Sarcocystis sp. from marsh deer is a different species from others using cervids as intermediate hosts. Therefore, we propose the name Sarcocystis blastoceris n. sp. for the species infecting marsh deer.

Invasive American mink (Neovison vison) as potential definitive host of Sarcocystis elongata, S. entzerothi, S. japonica, S. truncata and S. silva using different cervid species as intermediate hosts

Canids and scavenger birds were shown to act as definitive hosts of numerous Sarcocystis species using members of the Cervidae family as an intermediate host, whereas definitive hosts spreading closely related S. elongata, S. entzerothi, S. japonica, S. matsuoae, S. rangiferi, S. truncata, S. silva and S. tarandi remain unknown. In the current study, the intestine samples of 40 American minks (Neovison vison) were molecularly tested for the presence of the above-mentioned Sarcocystis spp. Species-specific PCR of cytochrome c oxidase subunit I (cox1) fragments and subsequent sequencing revealed the presence of sporocysts/oocysts of five species, S. elongata (n=2), S. entzerothi (n=10), S. japonica (n=4), S. silva (n=13) and S. truncata (n=21) in the analysed samples. Sarcocystis infection was confirmed in 32/40 (80%) examined samples. In addition, half of the infected animals (50%) were infected with multiple Sarcocystis species suggesting that American minks had access to meat of different deer species, such as roe deer, red deer and sika deer. This causes concern about compliance of hunters and game processing companies with game waste management rules. Further research on the involvement of mustelids in the transmission of various Sarcocystis spp. from different geographical locations is needed.

Zoonotic Sarcocystis

Apicomplexan species in the genus Sarcocystis form tissue cysts, in their intermediate hosts, similar to those established in chronic toxoplasmosis. More than 200 species are known, but just a few are known to threaten human health owing to infection in livestock species. Intestinal sarcocystosis occurs when people consume raw or undercooked beef contaminated with Sarcocystis hominis or S. heydorni or undercooked pork contaminated with S. suihominis. Those infections may cause mild enteritis, but most infections are thought to be asymptomatic. People also become dead-end (intermediate) hosts for non-human Sarcocystis spp. after accidentally ingesting sporocysts, leading to extraintestinal sarcocystosis. The clinical spectrum may range from asymptomatic muscle cysts to a severe, acute, eosinophilic myositis associated with systemic symptoms with peripheral eosinophilia. Most human cases have been described from Southeast Asia, but Sarcocystis parasites have a worldwide distribution, especially where livestock is raised, and human infections in other areas have been described but may be underrecognized.

Sarcocystis spp. infection in South American deer huemul (Hippocamelus bisulcus) and pudu (Pudu puda) from Patagonian National Parks, Argentina

Sarcocystis spp. are intracellular protozoan parasites with heteroxenous life cycles. This study described Sarcocystis spp. infection in adult South American native deer huemul (Hippocamelus bisulcus) and pudu (Pudu puda). Heart, diaphragm, tongue, and skeletal muscle samples were collected from 5 huemuls and 2 pudus, found dead in National Parks. Direct microscopic examination, transmission electron microscopy, PCR, and sequencing were performed. Sarcocystis spp. microscopic thin-walled cysts were identified in 3 huemuls and 1 pudu. Several cysts from 1 huemul and 1 pudu were observed by TEM; ultrastructure was similar to previously reported as cyst wall type 17 and types 2 and 8, respectively. Fragments of the 18S rRNA and cytochrome c oxidase subunit I (cox1) genes were amplified and sequenced from 3 individual cysts from 2 huemuls and 2 cysts from the pudu. The sequences from huemuls showed a high identity among them (> 99%) at both amplified targets. The highest identities were > 99.7% at 18S rRNA and 93% at cox1 with S. tarandivulpes sequences. The 18S rRNA gene sequences from pudus showed an identity > 99.7% with Sarcocystis sp., S. taeniata, and S. linearis sequences, while the cox1 sequences were different, one showing 99.42% identity with S. venatoria and the other 98.22% with S. linearis. A single species, similar to S. tarandivulpes, was identified in all huemul samples while 2 molecularly different Sarcocystis spp. were found in 1 pudu with high similarities to either S. venatoria or to S. linearis, S. taeniata-like, and S. morae. Based on the cox1 sequence identities, at least the Sarcocystis sp. in huemuls might represent a new species, primarily occurring in this host. Additional sarcocyst isolates from both hosts need to be examined molecularly in order to firmly establish whether these species are indeed native to huemuls and/or pudus or are derived from introduced deer species.

Sarcocystis menglaensis n. sp. (Apicomplexa: Sarcocystidae) from Williamson's mouse deer Tuagulus williamsoni (Kloss) (Artiodactyla: Tragulidae)

Williamson's mouse deer, Tuagulus williamsoni (Kloss), is one of the smallest ungulates among tragulid species found in northern Thailand, and Yunnan Province, China. Here we describe Sarcocystis menglaensis n. sp., infecting two of 14 (14.3%) Williamson's mouse deer from south-western China. By light microscopy, sarcocysts of S. menglaensis are microscopic, up to 2,170 μm in length, and have a striated sarcocyst wall with 1.5-3.6 μm long palisade-like protrusions. Transmission electron microscopy observations revealed that sarcocyst wall is of "type 10f", and has numerous villar protrusions folded over the cyst wall. The villar protrusions contained microtubules dispersed throughout the protrusions. Phylogenetic analysis based on 18S rDNA and mitochondrial cox1 gene sequences indicated that S. menglaensis shared a close affinity with species of Sarcocystis Lankester, 1982 from ruminants, which utilise felids as definitive hosts.

Sarcocystis entzerothi n. sp. from the European roe deer (Capreolus capreolus)

In the present study, we describe Sarcocystis entzerothi n. sp. from the European roe deer (Capreolus capreolus) based on the microscopical and DNA analysis. By light microscopy (LM), cysts of S. entzerothi were spindle-shaped with pointed tips, 950-1900 × 70-150 μm in size and had 5-6 μm long finger-like cyst wall protrusions. Cyst wall of S. entzerothi by transmission electron microscopy (TEM) was type 10a-like; villar protrusions were up to 1.2 μm wide, densely packed, lying about 0.1 μm between each other, had profuse microgranules and microfilaments, parasitophorous vacuolar membrane had many minute invaginations, and the ground substance layer measured up to 0.4 μm. This species is morphologically similar to Sarcocystis silva, previously found in the roe deer and the moose (Alces alces). By LM, cysts of S. silva were cigar-shaped with blunted tips, measured 1000-1500 × 130-184 μm, and had 7-8 μm long finger-like cyst wall protrusions. Under TEM, S. silva had no clear differences from S. entzerothi in their cyst wall ultrastructure. Having examined six roe deer hunted in Lithuania, cysts of S. entzerothi and S. silva were identified in four and two animals, respectively. These two Sarcocystis species could be morphologically differentiated according to the shape of the cysts and the length of protrusions. The species examined showed 95.6-96.1 % and 85.6-86.9 % sequence identity within 18S ribosomal DNA (rDNA) and cox1, respectively, and therefore they could be clearly distinguished by means of molecular methods. It should be noted that in the 18S rDNA phylogenetic tree, S. entzerothi from the roe deer was placed together with one sequence of Sarcocystis sp. from the Lithuanian red deer (Cervus elaphus) demonstrating the same species. Based on 18S rDNA and cox1 sequences, S. entzerothi was more closely related to Sarcocystis species transmitted via felids than canids.

Morphological and molecular characterization of Sarcocystis taeniata and Sarcocystis pilosa n. sp. from the sika deer (Cervus nippon) in Lithuania

The diaphragm muscles of eight sika deer (Cervus nippon) bred in Lithuania were examined for Sarcocystis cysts. Two Sarcocystis species, Sarcocystis taeniata, which were previously reported in Canadian moose (Alces alces) and Argentinean red deer (Cervus elaphus), and Sarcocystis pilosa n. sp. were described using light microscopy (LM), transmission electron microscopy (TEM), 18S ribosomal DNA (rDNA), and subunit I of cytochrome c oxidase (cox1) sequences analysis. By LM, cysts of S. taeniata were 424.8 × 57.9 (200-837 × 30-100) μm in size and had a thin (up to 1 μm) and smooth cyst wall, while short ribbon-like protrusions arising from broadened cone-shaped bases were seen under TEM. Cysts of S. pilosa (by LM) were ribbon-shaped, measured 848.5 × 63.8 (350-1700 × 30-125) μm and had thin 7-8-μm long hair-like protrusions. By TEM, cyst wall was type 7a-like; protrusions arose from 0.3 μm wide dome-shaped base with minute indentations of the parasitophorous vacuolar membrane near it, the surface of protrusions seemed to be smooth, and the ground substance layer was thin (0.18-0.22 μm). The 18S rDNA, in contrast to the cox1, lacked variability to discriminate S. pilosa from closely related Sarcocystis hjorti from the red deer and moose. S. taeniata, but not S. pilosa, showed a considerable intraspecific variation in both genes analyzed. The phylogenetic analyses based on 18S rDNA and cox1 sequences suggest that canids are definitive hosts of both S. taeniata and S. pilosa. This paper represents the first identification of Sarcocystis species in the sika deer by morphological and molecular methods.

Sarcocystosis in wild red deer (Cervus elaphus) in Patagonia, Argentina

Sarcocystis spp. are protozoan parasites with a heteroxenous life cycle, which produce cysts in the muscle of herbivorous animals. In these animal species, sarcocystosis is frequently asymptomatic, although it may occur with high prevalence. Seven Sarcocystis spp. have been described in red deer (Cervus elephus). The aim of this study was to determine the prevalence of sarcocystosis, and to perform the morphological and molecular characterization of Sarcocystis spp. found in wild red deer of the Nahuel Huapi National Park (NHNP), Patagonia, Argentina. Full necropsies of 62 red deer killed by hunters in the NHNP and neighboring areas were performed. Samples of heart and skeletal muscle were examined histologically and selected samples were also examined by transmission electron microscopy (TEM), PCR and sequencing. Sarcocystis spp. thin walled cysts were detected in 62 % (38/62) of heart, and in 22 % (3/14) of skeletal muscle samples examined histologically. TEM revealed a smooth and thin cyst wall (≤1 μm), with scarce and separated ribbon-like protrusions. A total of three partial and one full 18S ribosomal RNA (rRNA) gene sequences were obtained, and showed the highest identity (≥99 %) with Sarcocystis taeniata, a species described in moose (Alces alces). The morphological and molecular results indicate that red deer in Argentina are frequently infected with S. taeniata, a species for which the definitive host is unknown. The present results also confirm that Sarcocystis spp. using cervids as intermediate host are not host-specific. Further studies are needed to improve the epidemiological knowledge of Sarcocystosis in red deer.

Molecular characterization of Sarcocystis species from Polish roe deer based on ssu rRNA and cox1 sequence analysis

Sarcocysts from four Polish roe deer were collected and examined by light microscopy, small subunit ribosomal RNA (ssu rRNA), and the subunit I of cytochrome oxidase (cox1) sequence analysis. This resulted in identification of Sarcocystis gracilis, Sarcocystis oviformis, and Sarcocystis silva. However, we were unable to detect Sarcocystis capreolicanis, the fourth Sarcocystis species found previously in Norwegian roe deer. Polish sarcocysts isolated from various tissues differed in terms of their shape and size and were larger than the respective Norwegian isolates. Analysis of ssu rRNA gene revealed the lack of differences between Sarcocystis isolates belonging to one species and a very low degree of genetic diversity between Polish and Norwegian sarcocysts, ranging from 0.1 % for Sarcocystis gracilis and Sarcocystis oviformis to 0.44 % for Sarcocystis silva. Contrary to the results of the ssu rRNA analysis, small intraspecies differences in cox1 sequences were found among Polish Sarcocystis gracilis and Sarcocystis silva isolates. The comparison of Polish and Norwegian cox1 sequences representing the same Sarcocystis species revealed similar degree of sequence identity, namely 99.72 % for Sarcocystis gracilis, 98.76 % for Sarcocystis silva, and 99.85 % for Sarcocystis oviformis. Phylogenetic reconstruction and genetic population analyses showed an unexpected high degree of identity between Polish and Norwegian isolates. Moreover, cox1 gene sequences turned out to be more accurate than ssu rRNA when used to reveal phylogenetic relationships among closely related species. The results of our study revealed that the same Sarcocystis species isolated from the same hosts living in different geographic regions show a very high level of genetic similarity.

Molecular identification of Sarcocystis spp. helped to define the origin of green pythons (Morelia viridis) confiscated in Germany

Sarcocystis spp. represent apicomplexan parasites. They usually have a heteroxenous life cycle. Around 200 species have been described, affecting a wide range of animals worldwide, including reptiles. In recent years, large numbers of reptiles have been imported into Europe as pets and, as a consequence, animal welfare and species protection issues emerged. A sample of pooled feces from four confiscated green pythons (Morelia viridis) containing Sarcocystis spp. sporocysts was investigated. These snakes were imported for the pet trade and declared as being captive-bred. Full length 18S rRNA genes were amplified, cloned into plasmids and sequenced. Two different Sarcocystis spp. sequences were identified and registered as Sarcocystis sp. from M. viridis in GenBank. Both showed a 95-97% sequence identity with the 18S rRNA gene of Sarcocystis singaporensis. Phylogenetic analysis positioned these sequences together with other Sarcocystis spp. from snakes and rodents as definitive and intermediate hosts (IH), respectively. Sequence data and also the results of clinical and parasitological examinations suggest that the snakes were definitive hosts for Sarcocystis spp. that circulate in wild IH. Thus, it seems unlikely that the infected snakes had been legally bred. Our research shows that information on the infection of snakes with Sarcocystis spp. may be used to assess compliance with regulations on the trade with wildlife species.

Genetic assemblage of Sarcocystis spp. in Malaysian snakes

Background

Sarcocystis species are protozoan parasites with a wide host range including snakes. Although there were several reports of Sarcocytis species in snakes, their distribution and prevalence are still not fully explored.

Methods

In this study, fecal specimens of several snake species in Malaysia were examined for the presence of Sarcocystis by PCR of 18S rDNA sequence. Microscopy examination of the fecal specimens for sporocysts was not carried as it was difficult to determine the species of the infecting Sarcocystis.

Results

Of the 28 snake fecal specimens, 7 were positive by PCR. BLASTn and phylogenetic analyses of the amplified 18S rDNA sequences revealed the snakes were infected with either S. nesbitti, S. singaporensis, S. zuoi or undefined Sarcocystis species.

Conclusion

This study is the first to report Sarcocystis infection in a cobra, and S. nesbitti in a reticulated python.

Parasites in ungulates of Arctic North America and Greenland: a view of contemporary diversity, ecology, and impact in a world under change

Parasites play an important role in the structure and function of arctic ecosystems, systems that are currently experiencing an unprecedented rate of change due to various anthropogenic perturbations, including climate change. Ungulates such as muskoxen, caribou, moose and Dall's sheep are also important components of northern ecosystems and are a source of food and income, as well as a focus for maintenance of cultural traditions, for northerners. Parasites of ungulates can influence host health, population dynamics and the quality, quantity and safety of meat and other products of animal origin consumed by people. In this article, we provide a contemporary view of the diversity of nematode, cestode, trematode, protozoan and arthropod parasites of ungulates in arctic and subarctic North America and Greenland. We explore the intricate associations among host and parasite assemblages and identify key issues and gaps in knowledge that emerge in a regime of accelerating environmental transition.

Description of Sarcocystis turdusi sp. nov. from the common blackbird (Turdus merula)

Cysts of Sarcocystis species were found in 24 of 44 (54·5%) examined blackbirds (Turdus merula). Under the light microscope, only 1 morphological type of cyst was found in all birds investigated. Ribbon-shaped cysts were long (the largest fragment found amounted to 7 mm) and of different thickness (25–206 μm). A cyst wall reached up to 3·5 μm and had finger-like protrusions. Under the transmission electron microscope, a single cyst isolated from 1 blackbird was studied. The cyst wall was 2·5–4·4 μm thick, had club- or irregularly-shaped and sometimes branched protrusions that differed in size. The content of cysts was divided into large chambers by septa. Orange segment-shaped cystozoites were 6·2 × 1·4 (5·5–7·2 × 1·2–1·5) μm. This type of cyst wall has never been described in Sarcocystis species isolated from birds, thus far. The results of 18S rDNA, 28S rDNA and ITS–1 region sequences showed that S. turdusi was most closely related to S. columbae, S. calchasi, S. wobeseri, S. cornixi and Sarcocystis sp. ex Accipiter nisus parasitizing birds. Phylogenetic results suggest that predatory birds are the most probable definitive hosts of S. turdusi.

Phylogenetic analysis of Sarcocystis nesbitti (Coccidia: Sarcocystidae) suggests a snake as its probable definitive host

Sarcocystis nesbitti was first described by Mandour in 1969 from rhesus monkey muscle. Its definitive host remains unknown. 18S rRNA gene of S. nesbitti was amplified, sequenced, and subjected to phylogenetic analysis. Among those congeners available for comparison, it shares closest affinity with those species of Sarcocystis which use snakes as definitive hosts. We therefore hypothesize that a snake may serve as the definitive host for S. nesbitti.

Detection of a morphogenetically novel Sarcocystis hominis-like in the context of a prevalence study in semi-intensively bred cattle in Italy

The aim of this study was to determine the prevalence of sarcosporidiosis in semi-intensively bred cattle in northwestern Italy. A diagnostic protocol was setup in which infected animals were identified by rapid histological examination of the esophagus, diaphragm, and heart and the detected Sarcocystis spp. were subsequently typed using conventional electron microscopy in combination with molecular techniques. Sarcosporidia cysts were detected in 78.1% of the animals and were seen most often in the esophagus. The cattle is intermediate host for Sarcocystis hominis (final host, humans and some primates), Sarcocystis cruzi (final host, domestic and wild canids), and Sarcocystis hirsuta (final host, wild and domestic cats).All these three species of Sarcocystis were identified, variously associated, with the following prevalence: S. cruzi (74.2%), S. hirsuta (1.8%), and S. hominis (42.7%). Furthermore, a new S. hominis-like (prevalence 18.5%), characterized by hook-like structures of villar protrusion and a different sequence of the 18S rRNA gene, was identified. The cattle sheds testing positive for zoonotic Sarcocystis were assessed for risk factors contributing to the maintenance of the parasite's life cycle. Significant associations emerged between consumption of raw meat by the farm owner, mountain pasturing, and absence of a sewerage system on the farm and cattle breed. Our study demonstrates that sarcosporidiosis may constitute a public health problem in Italy and indicates several issues to be addressed when planning surveillance and prevention actions. The applied diagnostic approach revealed that cattle can harbor a further type of Sarcocystis, of which life cycle and zoonotic potential should be investigated.

Corvid birds (Corvidae) act as definitive hosts for Sarcocystis ovalis in moose (Alces alces)

Epidemiological data and a unique phylogenetic position had suggested that Sarcocystis ovalis in moose and red deer might use a definitive host other than canids, felids, or humans. Corvid birds and rats were therefore evaluated as potential definitive hosts for this species in a small pilot study. Four laboratory rats were each inoculated with 10 or 25 sarcocysts of S. ovalis isolated from moose, but no Sarcocystis oocysts were detected in their intestinal mucosa upon euthanasia 2 to 3 weeks later. At a site where large flocks of corvid birds (hooded crows, ravens and European magpies) fed on remnants of moose carcasses during the hunting period in October, fresh bird droppings were collected on the ground and examined microscopically and by molecular methods. By microscopy, a small number of typical Sarcocystis sporocysts, measuring 12.8 × 8.4 μm, were found in the faecal samples. These sporocysts were identified as belonging to S. ovalis by a polymerase chain reaction assay using specific primer pairs targeting the ssu rRNA gene, followed by sequence analysis. The intestinal contents of a crow and two magpies shot near the dumping site were also examined. Sarcocystis oocysts (16.1 × 12.4 μm) and free sporocysts (12.5 × 7.9 μm) were found in the intestinal mucosa/contents of one magpie (Pica pica). These oocysts/sporocysts were also found to belong to S. ovalis by the same molecular assay. This is the first report of corvid birds acting as definitive hosts for a species of Sarcocystis.

The red fox (Vulpes vulpes) and the arctic fox (Vulpes lagopus) are definitive hosts of Sarcocystis alces and Sarcocystis hjorti from moose (Alces alces)

The aim of this study was to determine whether foxes might act as definitive hosts of Sarcocystis alces in moose. In 2 experiments, 6 silver foxes (Vulpes vulpes) and 6 blue foxes (Vulpes lagopus) were fed muscle tissue from moose containing numerous sarcocysts of S. alces, and euthanazed 7-28 days post-infection (p.i.). Intestinal mucosal scrapings and faecal samples were screened microscopically for Sarcocystis oocysts/sporocysts, which were identified to species by means of species-specific primers and sequence analysis targeting the ssu rRNA gene. All foxes in both experiments became infected with Sarcocystis; the oocysts were fully sporulated by 14 days p.i., containing sporocysts measuring 14-15 x 10 microm. Molecular identification revealed that the oocysts/sporocysts belonged to 2 species, S. alces and Sarcocystis hjorti, although sarcocysts of S. hjorti were only identified in moose subsequent to the infection of foxes. In the first experiment, all 8 foxes also became infected with a Hammondia sp. derived from moose, shedding unsporulated, subspherical oocysts, measuring 10-12 microm in diameter, from 6-7 days p.i. onwards. The study proved that canids (the red fox and arctic fox) are definitive hosts for S. alces and S. hjorti, as had been inferred from the phylogenetic position of these species.

Diagnosis of Sarcocystis spp. in cattle (Bos taurus) and water buffalo (Bubalus bubalis) in Northern Vietnam

Our aim was to develop a method for species diagnosis and to obtain data on the prevalence of Sarcocystis infections in cattle and water buffalo in the Son La Province of Northern Vietnam. Meat samples of naturally infected animals were examined by light and electron microscopy as well as by molecular methods. A PCR of part of the 18S rDNA gene followed by RFLP analysis was modified to detect infections with different Sarcocystis spp. in cattle and water buffaloes slaughtered in the Son La Province. It showed to be an economical method to detect multiple infections with Sarcocystis spp. Sequence analysis of the PCR amplicons was performed with selected samples and the results were compared with published sequences. With these methods the following Sarcocystis spp. were identified in cattle: Sarcocystis hirsuta, Sarcocystis cruzi and Sarcocystis hominis. Water buffaloes were infected with Sarcocystis fusiformis, S. cruzi, S. hominis and S. hirsuta. The results indicate that Sarcocystis spp. infecting cattle are also able to infect water buffaloes. So the validity of certain Sarcocystis spp. of water buffalo is discussed. Bovine lifestock in Northern Vietnam were commonly infected with Sarcocystis spp.

Sarcocystis in Norwegian roe deer (Capreolus capreolus): molecular and morphological identification of Sarcocystis oviformis n. sp. and Sarcocystis gracilis and their phylogenetic relationship with other Sarcocystis species

Fresh muscle tissue from six roe deer from Southeastern Norway was examined for sarcocysts. Cysts were excised and morphologically classified by light microscopy, and some cysts were further examined by scanning electron microscopy or DNA amplification and sequencing of the small subunit (ssu) rRNA gene. Two Sarcocystis species, Sarcocystis gracilis and Sarcocystis oviformis n. sp., were found and described by morphological and molecular methods. S. gracilis was found in all animals, whereas S. oviformis was found in only one roe deer. Polymerase chain reaction identification was necessary for definitive species identification, since cysts of S. gracilis varied in surface structure and since cysts of both S. gracilis and S. oviformis were morphologically indistinguishable from sarcocysts in other cervidae. Phylogenetic analyses based on complete ssu rRNA gene sequences revealed a close relationship between S. gracilis and other canine-transmitted Sarcocystis species, whereas S. oviformis formed a well-supported group with Sarcocystis hardangeri of reindeer and Sarcocystis ovalis of moose.

Sarcocystis in moose (Alces alces): molecular identification and phylogeny of six Sarcocystis species in moose, and a morphological description of three new species

Muscle tissues from 34 moose from Southeastern Norway and two moose from Canada were examined. Sarcocysts were excised and morphologically classified by light microscopy, and some cysts were further examined by scanning electron microscopy or DNA amplification and sequencing at the small subunit (ssu) rRNA gene. In Norwegian moose, three sarcocyst types were recognized, yet five Sarcocystis species were found by sequence analysis. New names were proposed for three species which could be characterised by both morphological and molecular methods, i.e., Sarcocystis alces, Sarcocystis ovalis, and Sarcocystis scandinavica. S. alces was the most prevalent species, whereas S. scandinavica and the two unnamed species were rare and might either use another principal intermediate host or a rare definitive host. The five species in Norwegian moose were different from Sarcocystis alceslatrans isolated from a Canadian moose. Phylogenetic analyses based on complete ssu rRNA gene sequences revealed a close relationship between the six Sarcocystis species from moose and species from reindeer and Sika deer. We conclude that molecular methods are necessary for unequivocal species identification, as different cervid hosts harbour morphologically indistinguishable sarcocysts.