Ultrastructure of the cyst wall of Sarcocystis species with canine final host in Japan

Prevalence and first molecular identification of Sarcocystis species in feces of domestic dogs (Canis familiaris) in Egypt

BACKGROUND

Sarcocystis species are obligatorily heteroxenous protozoan parasites with predator-prey life cycles. Global Knowledge about the epidemiology and the distribution pattern of different Sarcocystis species in dog feces are very scarce. Therefore, the current investigation was conducted to declare the occurrence of Sarcocystis in the fecal specimens of the most common canids in Egypt, the domestic dogs, and to identify the species present using various parasitological and molecular approaches.

METHODS

A total of 100 dog fecal samples were collected and screened using fecal sugar flotation test for the presence of Sarcocystis oocysts/sporocysts. Additionally, thirty samples were used for genomic DNA extraction. The 18S rRNA gene fragment was the target of primers for a PCR, followed by purification and sequencing of the amplicons.

RESULTS

Currently, the results obtained reviewed that 4% of fecal samples were positive for Sarcocystis spp. using LM. Additionally, Sarcocystis spp. were verified in sixteen dogs (53.3%, 16/30) using PCR and subsequent sequencing protocols. Statistically, insignificant difference in prevalence of sarcocystosis relative to age and gender was noticed. Morphologically, the detected sporocysts measured 13.2-16.0 × 9.4-11 μm. Based on the 18S rRNA gene, sequencing analysis of amplicons from sporocysts DNA revealed 99.82% nucleotide homology with published S. tenella partial nucleotide sequences from sheep in Iraq and Iran.

CONCLUSIONS

This is the first molecular evidence in support of the final host role of domestic dogs in the life cycle of S. tenella in Egypt, which provides a precious diagnostic tool for further epidemiological studies and for the assessment of the effectiveness of control measures for this disease.

Molecular Identification, Pathogenesis, and Life Cycle of Sarcocystis cruzi from Cattle (Bos taurus) in New Valley Governorate, Egypt

Sarcocystis cruzi was identified by molecular methods from an intermediate host, cattle (Bos taurus), in El-Kharga, New Valley Governorate, Egypt, and its life cycle and pathogenicity were studied in the final host, dogs (Canis familiaris). 600 slaughtered cattle aged 6-8 years (480/120 males/females) were included. In addition, three laboratory-bred, coccidian-free puppies aged 2-3 months were fed infected bovine muscles to locate the definitive host and analyze sporogony. 18S rRNA-specific gene primers were used for DNA amplification from esophageal muscles. These polymerase chain reaction (PCR) amplicons were subjected to restriction fragment length polymorphism (RFLP) and molecular sequence analysis. Infection was detected in 78.8% (473/600; 95% CI, 75.56-82.11%). Histopathological examination of esophageal muscles showed oval- to spherical-shaped cysts, 96.7 μm wide by 326.9 μm long; cysts in cardiac muscles were ovoid and smaller. Infected puppies began shedding sporocysts in feces 7 days post-inoculation and showed distorted organ architecture, severe cellular damage, and inflammatory lesions in liver, kidney, esophagus, and stomach. Three oocysts with different shapes and sizes were identified. Partial 18S rRNA gene sequences of isolated New Valley sarcocysts were identical to S. cruzi isolated from different areas, verifying their genetic relatedness. Our analysis suggests that S. cruzi is the most prevalent in slaughtered cattle in New Valley Governorate, Egypt.

Distribution, prevalence, and intensity of Sarcocystis infections in sika deer (Cervus nippon) of free-ranging populations in Germany and Austria

Sika deer (Cervus nippon), which are native to the Japanese islands and the adjacent mainland of eastern Asia, have been introduced into Europe and established free-ranging populations in several countries. Various Sarcocystis species have been identified recently from farmed "mainland sika" deer in Lithuania and native "Japanese sika" deer in Japan. To study the distribution, prevalence and intensity of Sarcocystis infection in free-ranging sika deer outside of their natural range heart and/or diaphragm samples of 311 animals from nine populations in Germany and Austria were examined by histology.Overall, sarcocysts were detected in either heart or diaphragm of 107/311 deer (34.4%) with prevalence ranging roughly from 5 to 50% among the populations. Considering the 263 animals with both heart and diaphragm available, prevalence varied significantly (p < 0.0001) among calves (20.2%), yearlings (40.3%), and adult deer (49.1%) but did not differ between male and female deer (48.3% vs. 43.7%; p = 0.6483). Occurrence of sarcocysts in heart vs. diaphragm indicated a marginal difference (27.8% vs. 20.9%; p = 0.0839). Intensity of infection in all but one heart positive and all diaphragm positive animals was low (< 10 sarcocysts per square centimeter muscle cut). While heart sarcocyst counts of yearlings and adult deer were higher than those of calves and were higher in male compared to female sika deer, diaphragm sarcocyst counts did not differ significantly between age groups and sexes. Sarcocystis infection was demonstrated at variable prevalence in sika deer in all populations but intensity is apparently low. Further studies are needed to identify the species of Sarcocystis infecting sika deer naturalized outside their natural range.

Morphometric Study of Microscopic Cysts of Sarcocystis Sp. in Sheep Carcasses

Muscular samples of the oesophagus and diaphragm of 335 sheep collected from the slaughterhouse of El Harrach were analyzed by the histopathological method to describe the morphology of two species of Sarcocystis: S. arieticanis and S. tenella. The cysts were counted and measured with a micrometer for their dimensions. A total of 895 cysts were measured. The width, length, shape index (length/width), the thickness of the wall and the length of the projections were recorded. The thick-walled cysts of S. tenella were 10—450 μm long (the mean ± SD value was 50.35 μm ± 1.380) and 1—110 μm (the mean ± SD value was 27.51 μm ± 0.533) wide. The cyst walls were 0.5—4 μm thick (the mean ± SD value was 1.547 μm ± 0.020) and provided with radial striations. The shape index was 1—14 μm (the mean ± SD value was 1.93 ± 0.045). While in the S. arieticanis, the cyst wall was thin and had long hair-like protrusions, the cysts measured 8—780 μm (the mean ± SD value was 123.13 μm ± 12.799) in length and 5—100 μm (the mean ± SD value was 37.00 μm ± 1.68) in width. The hair-like protrusions reached a length of 3—14 μm (the mean ± SD value was 5.428 ± 0.353) and the shape index was 1—17 μm (the mean ± SD value was 3.10 ± 0.281). For the length, the width and the shape index, the differences were statistically significant between thin-walled cysts and thick-walled cysts. The general structural features of the cysts, previously described by other authors, were confirmed.

Morphological and molecular characteristics of seven Sarcocystis species from sika deer (Cervus nippon centralis) in Japan, including three new species

Samples of diaphragm were collected from 53 sika deer from Gifu Prefecture, Japan; 220 sarcocysts were isolated, examined in wet mounts and classified according to their cyst wall protrusions. The sarcocysts were then examined molecularly in order to assign them to different species. All but 11 of the 220 sarcocysts were initially identified by means of a multiplex PCR assay targeting cox1 of five species, whereas the remaining 11 sarcocysts were identified by standard PCR and sequencing. DNA from selected sarcocysts was used for PCR amplification and sequencing of cox1 (59 sequences) and 18S rDNA (23 sequences). The 220 sarcocysts comprised seven major cox1 sequence types or species. Types 4 and 7 were assigned to the known species Sarcocystis pilosa and Sarcocystis ovalis, whereas types 1, 3 and 5 were considered to represent three new species, for which the names Sarcocystis japonica, Sarcocystis matsuoae and Sarcocystis gjerdei have been proposed. Types 2 and 6 were most similar to Sarcocystis tarandi and Sarcocystis taeniata, respectively, but could not be unequivocally assigned to these species. Sarcocysts belonging to S. japonica were macroscopic with fairly thick finger-like protrusions, whereas most sarcocysts of the six other species were microscopic. Sarcocysts of S. cf. tarandi and S. matsuoae were spindle-shaped and possessed thin finger-like cyst-wall protrusions. Sarcocysts of S. pilosa and S. gjerdei had similar hair-like protrusions, whereas those of S. cf. taeniata had a smooth surface. Sarcocysts of S. japonica, S. pilosa, S. cf. tarandi, S. gjerdei, S. matsuoae, S. cf. taeniata and S. ovalis were found in 50 (94.3%), 29 (54.7%), 22 (41.5%), 10 (18.9%), 8 (15.1%), 6 (11.3%) and 1 (1.9%) of the 53 sika deer examined, respectively. An improved multiplex PCR assay targeting cox1 was developed, through which the seven Sarcocystis spp. found in the present study could be identified.

First Case Report of Possible Sarcocystis truncata-induced Food Poisoning in Venison

Along with the increase in consumption of raw animal meat, the prevalence of food poisoning is increasing. A 67-year-old Japanese man had eaten raw venison 4 hours prior to the beginning of vomiting. Many white cysts were discovered in the venison, with numerous bradyzoites being detected after the cysts were punctured. The presence of the Sarcocystis spp. 18S rRNA gene was detected by polymerase chain reaction, and Sarcocystis truncata was isolated from the venison. Sarcocystis truncata has not previously been identified in sika deer (Cervus nippon) in Japan. This is the first report of possible Sarcocystis truncata-induced food poisoning following consumption of venison.

Ultrastructural and Molecular Identification of the sarcocysts of Sarcocystis tenella and Sarcocystis arieticanis Infecting Domestic Sheep (Ovis aries) from Egypt

BACKGROUND

In spite of the global economic significance of sheep production, little is known about the prevalence of various Sarcocystis spp. infecting the domestic sheep (Ovis aries) in Egypt.

MATERIALS AND METHODS

Muscle samples were collected from 175 sheep (> 2 years) slaughtered at El-Mahalla El-Kubra abattoir, Gharbia governorate, Egypt. Samples were initially examined by naked eye for the existence of macrosarcocysts. The microscopic sarcocysts were detected and identified using the light microscopy and the Transmission electron microscopy (TEM). Different microscopic species of ovine Sarcocystis were molecularly confirmed by PCR, sequence analyses and phylogeny.

RESULTS

Preliminary light microscopic inspection of the muscle specimens revealed the existence of only the microscopic sarcocysts of Sarcocystis tenella and Sarcocystis arieticanis in 152 (86.8%) out of the175 examined animals. Sarcoysts of S.tenella had striated thick cyst wall that amounted from 3.5-5.5 μm in thickness whereas, S.arieticanis sarcocysts had a thin cyst wall that ranged from 1-3 μm in thickness. S.tenella sarcocysts were detected in 115 sheep (65.7%), and were more prevalent than those of S.arieticanis, observed only in 68 sheep (38.8%). No macroscopic sarcocysts were observed in any of the examined carcasses. Transmission electron microscopy (TEM) of the cyst wall of S.tenella revealed the existence of the short stubby villar protrusions (VP) with the characteristic disk-like structures at the tips of the (VP). While, TEM of S.arieticanis showed that the cyst wall had elongated tubular protrusions that measured approximately 5-7 μm in length. Each (VP) consisted of a dome-shaped base (0.3-0.9 μm in diameter), a relatively thick middle portion (0.1-0.3 μm) in width, and a thin hair-like distal portion that measured about (0.03 x 1-4.5 μm).

CONCLUSION

Comparative analyses of the sequences of the four genetic markers (18S rRNA, 28S rRNA, mitochondrial cox1 and ITS-1) for S.tenella and S.arieticanis isolates detected herein, revealed genetic variations of 95% and 95- 96% among the different isolates on the level of the 18S rRNA and 28S rRNA, respectively. Whereas, the cox1 and ITS-1 shared sequence identities of 76-78% and 70-73%, respectively. S.tenella was strongly related to S.capracanis infecting goats (Capra hircus). Sequence identity of 98% on the level of 18S rRNA, 28S rRNA genes was observed between the currently identified isolates of S.tenella and the formerly GenBank deposited isolates of S.capracanis. While, cox1 sequences shared identities of 92-93%. Furthermore, S.arieticanis isolates identified here were closely related to the formerly published sequences of S.hircicanis. The 18S rRNA and 28S rRNA sequences of S.arieticanis shared 98% and 94-95% identities with those of S.hircicanis, respectively. However, 87-88% homologies were observed between the cox1 sequences of S.arieticanis and S.hircicanis. Consequently, cox1 and ITS-1 gene sequences act as better genetic markers than 18S rRNA and 28S rRNA sequences for the characterization of ovine Sarcocystis spp. Maximum parsimony analyses based on the sequences of three genetic markers, (18S rRNA, 28S rRNA and mitochondrial cox1), yielded the same placement of the currently identified isolates of the two taxa (S.tenella and S.arieticanis) within a clade of Sarcocystis species with carnivorous animals as known, or assumed, final hosts.

Molecular Characterization of Sarcocystis Species Isolated from Sheep and Goats in Riyadh, Saudi Arabia

Simple Summary

In this article, we investigated the occurrence of Sarcocystis species in samples of sheep and goats obtained from slaughterhouses in Riyadh, Saudi Arabia. We searched for tongue, heart, esophagus, diaphragm and skeletal muscle tissues. Fragments of these tissues were investigated by macroscopic evaluations, direct optical microscopy of tissue fragments, optical microscopy of digested fragment sediment, transmission electron microscopy and PCR followed by nucleotide sequencing. From the set of information obtained, we searched 230 sheep, and 84 goats; 91 and 36 were found to be infected, respectively. Transmission electron microscopy (TEM) revealed Sarcocystis tenella (S. tenella) in sheep and Sarcocystis capracanis (S. capracanis) in goats. Sarcocystis species were confirmed in Saudi Arabian sheep and goats by molecular testing. S. capracanis was most closely related to S. tenella, with the mitochondrial cytochrome c oxidase subunit I gene (COX1) sequences sharing a (91.7%) identity.

Abstract

Sarcocystosis is induced by species of Sarcocystis, which is an intracellular protozoan parasite in the phylum Apicomplexa. The diversity and importance of Sarcocystis species in sheep and goats in Saudi Arabia are poorly understood. In this study, the tongue, esophagus, heart, diaphragm, and skeletal muscles were collected from 230 sheep and 84 goats, and the tissues were examined for the presence of Sarcocystis species by macroscopic examination and light microscopy. Microscopic Sarcocystis species cysts were found in both sheep and goats. Transmission electron microscopy (TEM) revealed S. tenella in sheep and S. capracanis in goats. Sarcocystis species were confirmed for the first time in Saudi Arabian sheep and goats by molecular testing. S. capracanis was most closely related to S. tenella, with the COX1 sequences sharing 91.7% identity. A phylogenetic analysis produced similar results and indicated that the Sarcocystis isolates were within a group of Sarcocystis species in which dogs were the final host. Finally, the Sarcocystis species cysts from sheep and goats could be grouped together, indicating that they were strongly related.

Prevalence and molecular characterisation of Sarcocystis miescheriana and Sarcocystis suihominis in wild boars (Sus scrofa) in Italy

A sample of the diaphragm was collected from each of 100 wild boars legally hunted in the Val Grande National Park in north-western Italy and examined for the presence of Sarcocystis infection by histological and molecular methods. In histological sections, thick-walled sarcocysts consistent with those of Sarcocystis miescheriana were detected in 32 wild boars. Genomic DNA extracted from diaphragm samples was initially subjected to PCR amplification of the internal transcribed spacer 1 (ITS1) region, and 97 wild boars were found to harbour a Sarcocystis infection at this screening. Selected DNA samples were then subjected to PCR amplification and sequencing of the ITS1 region and the 18S and 28S ribosomal RNA (rRNA) genes of the nuclear ribosomal DNA unit, while all positive samples were subjected to PCR amplification of the mitochondrial cytochrome c oxidase subunit I (cox1) gene. S. miescheriana was identified in 97 wild boars (97%), while the zoonotic Sarcocystis suihominis was identified in one wild boar (1%), which also harboured S. miescheriana. Intra-specific sequence variation was found in all four DNA regions of S. miescheriana examined and in the 18S rRNA gene and ITS1 region of S. suihominis. The partial cox1 gene was amplified and sequenced from 72 isolates of S. miescheriana, yielding 43 haplotypes with pairwise sequence identities of 97.6-99.9%. These haplotypes were 79.1-79.8% identical with the cox1 sequence of S. suihominis. Phylogeny based on cox1 sequences placed S. miescheriana and S. suihominis as sister species within a clade comprising mainly Sarcocystis spp. of ruminants with felids as known or presumed definitive hosts. The same was true for the phylogeny based on 18S rRNA gene sequences.

Effects of temperature, pH and curing on the viability of Sarcocystis, a Japanese sika deer (Cervus Nippon centralis) parasite, and the inactivation of their diarrheal toxin

Recently, the Sarcocystis parasite in horse and deer meat has been reported to be a causative agent of acute food poisoning, inducing nausea, vomiting and diarrhea. Compared with other causative agents, such as bacteria, viruses and other parasites, in deer meat, the Sarcocystis species parasite, including its stability under various conditions, is poorly understood. In this study, we assessed the viability of Sarcocystis spp. and the activity of their diarrhea toxin (a 15-kDa protein) in deer meat under conditions of freezing, cold storage, pH change and curing. In addition, the heat tolerance was assayed using purified bradyzoites. The results showed that the species lost viability by freezing at −20, −30 and −80°C for <1 hr, heating at 70°C for 1 min, alkaline treatment (pH 10.0) for 4 days and addition of salt at 2.0% for <1 day. Immunoblot assays showed that the diarrhea toxin disappeared together with the loss of viability. However, the parasite survived cooling at 0 and 4°C and acidification (pH 3.0 and 5.0) for more than 7 days with the diarrhea toxin intact. These results provide useful information for developing practical applications for the prevention of food poisoning induced by diarrheal toxin of Sarcocystis spp. in deer meat during cooking and preservation.

Morphological and molecular identification of Sarcocystis spp. from the sika deer (Cervus nippon), including two new species Sarcocystis frondea and Sarcocystis nipponi

Diaphragm muscles of 25 sika deer (Cervus nippon) farmed in Lithuania were examined for sarcocysts of Sarcocystis species. Two new Sarcocystis species, Sarcocystis frondea and Sarcocystis nipponi, were observed using light microscopy (LM) and transmission electron microscopy (TEM) and characterized by 18S ribosomal DNA (rDNA) and subunit I of cytochrome c oxidase (cox1) sequence analyses. By LM, sarcocysts of S. frondea and S. nipponi were ribbon-shaped and had finger-like sarcocyst wall protrusions, respectively. Under TEM, protrusions of S. frondea were about 9 × 1-1.5 μm, filled with clearly visible electron-dense substance and microtubules, type 39-like. Whereas, protrusions (about 9 × 0.2 μm) of S. nipponi arose from dome-shaped bases were filled with microtubules extending to the ground substance layer, type 9o-like. Moreover, three known Sarcocystis spp., Sarcocystis entzerothi, Sarcocystis ovalis, and Sarcocystis truncata previously described in other cervids as intermediate hosts, were characterized in sika deer. The cox1 was more suitable than 18S rDNA delimitating closely related Sarcocystis species from cervids. The phylogenetic results suggest that scavenger birds could be definitive hosts of S. frondea. According to the summarized morphological data on Sarcocystis found in the sika deer, such host should harbor at least nine different Sarcocystis species.

Morphological and molecular characterization of four Sarcocystis spp., including Sarcocystis linearis n. sp., from roe deer (Capreolus capreolus) in Italy

Fresh (frozen/thawed) muscle samples from four 2-12-year-old roe deer (Capreolus capreolus) from the Sondrio province in north-eastern Italy were examined under a dissecting microscope, and about 180 sarcocysts were isolated and identified to morphological type in wet mounts by light microscopy (LM). Seventy-seven of these sarcocysts were subsequently examined by molecular methods, comprising polymerase chain reaction (PCR) amplification and sequencing of the partial cytochrome c oxidase subunit I gene (cox1) of all isolates, as well as PCR amplification, cloning and sequencing of the complete18S ribosomal RNA (rRNA) gene of two isolates of each species found. By LM, three major sarcocyst types were recognised: spindle-shaped sarcocysts, 0.5-3 mm long, either with no clearly recognisable protrusions (thin-walled) or with finger-like protrusions (thick-walled); and slender, thread-like sarcocysts, 2-3 mm long, with hair-like protrusions. Sequencing of cox1 revealed that the sarcocysts belonged to four different species. Those with no visible protrusions either belonged to Sarcocystis gracilis (n = 24) or to a Sarcocystis taeniata-like species (n = 19), whereas those with finger- and hair-like protrusions belonged to Sarcocystis silva (n = 27) and Sarcocystis capreolicanis (n = 7), respectively. The 19 cox1 sequences of the S. taeniata-like species, comprising five haplotypes, differed from each other at 0-16 of 1038 nucleotide positions (98.5-100% identity). They differed from 25 previous cox1 sequences of S. taeniata from moose and sika deer (with 98.0-100% intraspecific identity), at 33-43 nucleotide positions (95.9-96.8% interspecific identity), and there were 20 fixed nucleotide differences between the two populations. In the phylogenetic analysis based on cox1 sequences, the two populations formed two separate monophyletic clusters. The S. taeniata-like species in roe deer was therefore considered to represent a separate species, which was named Sarcocystis linearis n. sp. At the 18S rRNA gene, however, the two species could not be clearly separated from each other. Thus, there was considerable intraspecific sequence variation in the 18S rRNA gene of S. linearis (98.1-99.9% identity between 24 sequences), which was similar both in magnitude and nature to the variation previously found in this gene of S. taeniata. The new 18S rRNA gene sequences of S. linearis shared an identity of 97.9-99.6% with those of S. taeniata (overlap between intra- and interspecific identity), and in the phylogenetic tree, sequences of the two species were interspersed. By scanning electron microscopy (SEM), the sarcocysts of S. linearis were found to possess regularly spaced, thin and narrow ribbon-like cyst wall protrusions (about 2.8-3.2 μm long, 0.3-0.4 μm wide and about 0.02-0.03 μm thick), terminating in a plate-like structure of the same thickness but with an elliptic outline (about 0.3-0.4 μm wide and 0.7-0.9 μm long). The terminal plates were connected in the middle with the band-like portion of the protrusions like the board of a seesaw (tilting board). The terminal plates of adjacent protrusions were neatly arranged in a hexagonal pattern resembling tiles on a roof. Together, they formed an outer roof-like layer facing the surrounding cytoplasm of the host cell and completely covering the band-like proximal portion of the protrusions, which overlapped and were stacked in three to four layers close to the cyst surface. The sarcocyst morphology of S. linearis was consistent with that of an unnamed Sarcocystis sp. in roe deer previously found by transmission electron microscopy in several countries, including Italy. A few sarcocysts of S. gracilis and S. silva were also examined by SEM, confirming the presence of regularly distributed, short knob-like protrusions in S. gracilis (as seen in previous SEM studies) and revealing tightly packed, erect 6-7-μm-long villus-like protrusions having regularly distributed round depressions on their surface in S. silva. The sequencing of cox1 of 7, 24 and 27 new isolates of S. capreolicanis, S. gracilis and S. silva, respectively, recovered 7, 11 and 10 new haplotypes from each of the three species and expanded our knowledge on the intraspecific sequence variation at this marker. Similarly, the study revealed a more extensive intragenomic sequence variation at the 18S rRNA gene of S. capreolicanis and S. silva than known from previous studies and confirmed a near absence of such variation in the 18S rRNA gene of S. gracilis.

Prevalence, morphology, and molecular characteristics of Sarcocystis spp. in domestic goats (Capra hircus) from Kunming, China

Despite the importance of worldwide goat production, little is known about the prevalence of Sarcocystis spp. in domestic goats (Capra hircus) in China. The aims of the present study were to determine prevalence of Sarcocystis spp. in domestic goats in Kunming, China, as well as to identify parasite species based on morphological characteristics and DNA sequence analysis. Only microscopic sarcocysts of Sarcocystis spp. were detected in 174 of 225 goats (77.3 %). By light and transmission electron microscopy, two species, i.e., Sarcocystis capracanis and Sarcocystis hircicanis, were identified. Two sarcocysts from each of the two species were randomly selected for DNA extraction; the 18S rRNA gene (18S rRNA), the 28S rRNA gene (28S rRNA), and the mitochondrial cytochrome c oxidase subunit 1 (cox1) were amplified by the polymerase chain reaction (PCR) and subsequently sequenced. The results were compared with other previously sequenced Sarcocystis species retrieved from GenBank. There was little sequence variation between two isolates of the same species. S. capracanis was most closely related with Sarcocystis tenella; 18S rRNA, 28S rRNA, and mitochondrial cox1 sequences shared identities of 95.7-99.1, 95.3, and 92.3-93.2 % with those of S. tenella, respectively. Thus, mitochondrial cox1 sequences seem to perform better than 18S rRNA sequences or 28S rRNA sequences for identification of the two species. S. hircicanis was most closely related to Sarcocystis arieticanis, i.e., 18S rRNA and 28S rRNA sequences of the former species shared 97.2-97.4 and 95.6-96.1 % identities with those of latter, respectively. Phylogenetic analysis inferred from the three genetic markers yielded similar results and indicated the two species were within a group of Sarcocystis species with canines as known, or presumed, definitive hosts.

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.

The resurrection of a species: Sarcocystis bovifelis Heydorn et al., 1975 is distinct from the current Sarcocystis hirsuta in cattle and morphologically indistinguishable from Sarcocystis sinensis in water buffaloes

In the mid-1970s, it was established through transmission experiments and ultrastructural studies of sarcocysts by transmission electron microscopy (TEM) that cattle was the intermediate host of three Sarcocystis spp. using dogs, cats and humans, respectively, as definitive hosts. The cat-transmitted species with microscopic sarcocysts was initially named Sarcocystis bovifelis, but it was soon renamed Sarcocystis hirsuta, since it was considered to be identical with a previously named species. In recent years, an apparently new species has been detected in cattle in several countries by molecular methods and TEM and found by both methods to be indistinguishable from Sarcocystis sinensis in water buffaloes. This species was recently named Sarcocystis rommeli. Beginning in August 2014, a thorough review of papers comprising TEM micrographs of thick-walled sarcocysts in cattle was made in order to determine whether S. sinensis-like sarcocysts had been reported previously under other designations. Surprisingly, the review showed that the species S. bovifelis Heydorn et al., 1975 as described from cattle in Germany was S. sinensis-like and that indistinguishable sarcocysts had also been found in cattle in New Zealand and Canada in the 1980s. However, in the New Zealand study, these small sarcocysts were erroneously thought to represent developmental stages of a species with ultrastructurally similar but macroscopic sarcocysts, since the macroscopic cysts were found to be infective for cats. Thus, in the late 1980s, the cat-transmitted S. bovifelis, after having been renamed S. hirsuta, was erroneously synonymised with a second cat-transmitted species in cattle and then slid into obscurity until recently being rediscovered as a S. sinensis-like species in cattle and then named S. rommeli. Following the erroneous synonymisation, the name S. hirsuta has consistently been used for a taxon with macroscopic sarcocysts, and this usage should be continued. The name S. bovifelis should again be used not only for the species originally described from cattle in Germany but also for morphologically indistinguishable taxa recently reported from cattle under the names S. sinensis and S. rommeli. Because of the morphological similarity between S. bovifelis and S. sinensis, it is likely that cats also act as definitive hosts for S. sinensis. The present paper also gives a thorough review of all research in the 1970s pertaining to S. bovifelis, including its development in cats and cattle; a review of reports of S. bovifelis-like sarcocysts in cattle, water buffaloes and other hosts; and a review of reports of the taxon currently named S. hirsuta in cattle. The usage of the name S. sinensis versus Sarcocystis dubeyi for the S. bovifelis-like taxon in water buffaloes is discussed, and the latter name is found to represent a nomen dubium since the original description concerned a mixture of a S. sinensis- and a Sarcocystis hominis-like species. Based on available transmission (TEM) and scanning electron microscopy (SEM) images, the three-dimensional configuration of the cyst wall protrusions of S. bovifelis/S. sinensis and the current S. hirsuta has been inferred and is described. The protrusions of S. bovifelis/S. sinensis are shaped like soft plastic tubes, having a cylindrical basal portion and a flattened distal portion, making them prone to fold over. The protrusions of the current S. hirsuta are thin, flattened and flexible rectangular structures (like a soft cover note book), which are attached to the cyst surface with a narrow stalk. The appearance of both types of protrusions in ultrathin sections viewed by TEM is highly dependent on how the sarcocysts and the protrusions themselves have been sectioned.

Sarcocystis arieticanis (Apicomplexa: Sarcocystidae) infecting the heart muscles of the domestic sheep, Ovis aries (Artiodactyla: Bovidae), from K. S. A. on the basis of light and electron microscopic data

In the present study, the heteroxenous life cycle of Sarcocystis species from three strains of the slaughtered sheep at Al-Azizia and Al-Saada abattoirs in Riyadh city, K.S.A., was studied. Muscle samples of the oesophagus, diaphragm, tongue, skeletal and heart muscles were examined. Varied natural infection rates in the muscles of the examined sheep strains were recorded as 83% in Niemy, 81.5% in Najdy and 90% in Sawakny sheep. Muscles of the diaphragm showed the highest infection level above all organs except Najdy sheep in which oesophagus has the highest rate. Also, the heart was the lowest infected organ (40% Niemy, 44% Najdy and 53% Sawakny). Microscopic sarcocysts of Sarcocystis arieticanis are easily identified in sections through the heart muscles of the domestic sheep Ovis aries (Artiodactyla: Bovidae). Cysts measured 38.5-64.4 μm (averaged 42.66 μm) in width and 62.4-173.6 μm (averaged 82.14 μm) in length. The validity of this species was confirmed by means of ultrastructural characteristics of the primary cyst wall (0.1-0.27 μm thick) which revealed the presence of irregularly shaped crowded and hairy-like projections underlined by a thin layer of ground substance. This layer consisted mainly of fine, dense homogenous granules enclosing the developing metrocytes and merozoites that usually contain nearly all the structures of the apical complex and fill the interior cavity of the cyst. Several septa derived from the ground substance divided the cyst into compartments. The merozoites were banana-shaped and measured 12-16 μm in length with centrally or posteriorly located nuclei. Experimental infection of carnivores by feeding heavily infected sheep muscles revealed that the dog, Canis familiaris, is the only final host of the present Sarcocystis species. Gamogony, sporogonic stages and characteristics of sporulated oocysts were also investigated.

A toxin isolated from Sarcocystis fayeri in raw horsemeat may be responsible for food poisoning

Food poisoning has been reported after the consumption of raw horsemeat in Japan. Diarrhea with a short incubation period is a common symptom in such cases of food poisoning. Cysts found in horsemeat ingested by patients have been identified as Sarcocystis fayeri based on morphological and genetic evaluation and findings from experimental feeding of cysts to dogs, which resulted in the excretion of sporocysts. The extracts of the horsemeat containing the cysts produced a positive enterotoxic response in the rabbit ileal loop test. Intravenous injection of a 15-kDa protein isolated from the cysts induced diarrhea and lethal toxicity in rabbits, and the protein produced enterotoxicity in the ileal loop test as did the extracts of the horsemeat containing the cysts. The partial amino acid sequence of the 15-kDa protein was homologous to the actin-depolymerizing factor of Toxoplasma gondii and Eimeria tenella. These findings indicate that the 15-kDa protein of S. fayeri is a toxin that causes food poisoning after consumption of parasitized horsemeat.

Molecular characterization of five Sarcocystis species in red deer ( Cervus elaphus), including Sarcocystis hjorti n. sp., reveals that these species are not intermediate host specific

Muscle tissue from 37 red deer from Norway was examined for sarcocysts. Sarcocysts from 2 reindeer were obtained for comparative studies. Cysts were excised and morphologically classified by light microscopy, scanning electron microscopy, and DNA sequence analysis. Five Sarcocystis species, Sarcocystis hjorti n. sp., Sarcocystis hardangeri, Sarcocystis ovalis, Sarcocystis rangiferi, and Sarcocystis tarandi, were found. All 5 species have previously been identified from either reindeer or moose by their sarcocyst morphology and/or ssu rRNA gene sequence. S. hjorti was the most prevalent species. Multiple variants of the ssu rRNA gene and the first internal transcribed spacer were found in S. rangiferi and S. tarandi from both red deer and reindeer. Phylogenetic analyses indicated that S. tarandi occurs in both red deer and reindeer, but it could not be clearly demonstrated whether the sequence variation within S. rangiferi between hosts was due to different paralogues or/and different species. DNA sequencing was necessary for definitive species identification, since the hair-like protrusions on the cysts of S. hjorti were not always recognizable by light microscopy and since different cervids harbour Sarcocystis species with highly similar cyst morphology of which at least some are not intermediate host specific.

Sarcocystis sp. from cattle slaughtered in Japan

Sarcocystis sp. was detected from cattle slaughtered in Saitama Prefecture, Japan. The cysts were 3,400-4,400 x 198-238 microm in size and had the thick cyst wall which was 7 to 10 microm thick and provided with finger-like villar protrusions. The protrusions were 8-9.5 x 2-2.5 microm in size and had microtubules in the core.

Sarcocystis suihominis detected for the first time from pigs in Japan

Sarcoystis suihominis was detected for the first time in Japan from the heart and diaphragm of 5 out 600 older culled breeding pigs slaughtered in Saitama Prefecture, Japan. Fresh cysts were 1,080-2,040 x 106-170 microns in size. Bradysoites measured 15 x 4 microns on average. The cyst wall was usually observed thick, 4-6 microns, and striated, but occasionally thin and smooth according to the difference in sectioning angle and in portion of cysts. Scanning electron microscopy showed that many palisade-like villar protrusions, 6-6 x 0.3-0.5 microns in size, were closely folded onto the surface of cyst. A small number of microtubules were seen in the core of protrusion. No dogs nor domestic cats fed with 20 fresh cysts each excreted oocysts or sporocysts in the feces throughout the experimental period of 30 days.

Sarcocystis mihoensis n. sp. from sheep in Japan

Sarcocystis mihoensis n. sp., a heteroxenous coccidium was detected from sheep in Japan and dogs were experimentally determined as the definitive host. The cysts were 1,300-2,100 x 200-300 microns in size and had the thick cyst wall which was 10 to 12 microns thick and provided with radial striated and finger-like villar protrusions. Two 6-month old dogs fed with the cysts passed sporocysts, 15-16 x 8-9 microns in size, in the feces from day 11 to days 57-60 after ingestion. No domestic cats fed with same cysts shed sporocysts throughout the experimental period.