Sarcocystis cruzi (Hasselmann, 1923) Wenyon, 1926: redescription, molecular characterization and deposition of life cycle stages specimens in the Smithsonian Museum.

Currently, 7 named Sarcocystis species infect cattle: Sarcocystis hirsuta, S. cruzi, S. hominis, S. bovifelis, S. heydorni, S. bovini and S. rommeli; other, unnamed species also infect cattle. Of these parasites of cattle, a complete life cycle description is known only for S. cruzi, the most pathogenic species in cattle. The life cycle of S. cruzi was completed experimentally in 1982, before related parasite species were structurally characterized, and before the advent of molecular diagnostics; to our knowledge, no archived frozen tissues from the cattle employed in the original descriptions remain for DNA characterization. Here, we isolated DNA from a paraffin-embedded kidney of a calf experimentally infected with S. cruzi in 1980; we then sequenced portions of 18S rRNA, 28S rRNA, COX1 and Acetyl CoA genes and verified that each shares 99­100% similarity to other available isolates attributed to S. cruzi from naturally infected cattle. We also reevaluated histological sections of tissues of calves experimentally infected with S. cruzi in the original description, exploiting improvements in photographic technology to render clearer morphological detail. Finally, we reviewed all available studies of the life cycle of S. cruzi, noting that S. cruzi was transmitted between bison (Bison bison) and cattle (Bos taurus) and that the strain of parasite derived from bison appeared more pathogenic than the cattle strain. Based on these newfound molecular, morphological and physiological data, we thereby redescribed S. cruzi and deposited reference material in the Smithsonian Museum for posterity.

Preliminary findings and molecular characterization of thin-walled Sarcocystis species in hearts of cattle and buffaloes in Thailand, Lao PDR, and Cambodia.

Cattle and buffaloes, popular protein sources worldwide, are intermediate hosts for several Sarcocystis species. These coccidian protozoans cause sarcocystosis resulting in subclinical and chronic infections in striated muscles by forming macrocysts or microcysts. In Thailand, Lao People's Democratic Republic, and Cambodia, Sarcocystis species have been reported, but molecular identification has been lacking. This study investigates the prevalence of infection, histo-morphology, and molecular identification of Sarcocystis species in hearts of cattle and buffalo sold in local markets. A phylogenetic tree inferred from a portion of the 18S ribosomal (r) RNA gene was used to identify the genus and species of Sarcocystis. The mitochondrial cytochrome c oxidase subunit 1 (cox-1 gene) was sequenced to confirm the species of host tissue. In Thailand, Sarcocystis was detected in 66.7% (14/21) of samples. In Lao People's Democratic Republic, 90% (9/10) of samples were infected and in Cambodia 100% (8/8). For the first time from these countries, we report Sarcocystis cruzi, Sarcocystis heydorni, and Sarcocystis levinei found in taurine cattle (Bos taurus) and water buffalo (Bubalus bubalis). Zoonotic protozoan transmission needs to be controlled by inspection activities by local health inspectors, and appropriate action is required at all points in the food chain by competent authorities to protect consumer health and prevent sarcocystosis in cattle and water buffaloes.

Detection and Identification of Sarcocystis cruzi (Protozoa: Apicomplexa) by Molecular and Ultrastructural Studies in Naturally Infected Korean Cattle (Bos taurus coreanae) from Daejeon, Korea.

To survey the prevalence of Sarcocystis infections, 210 heart samples were collected from Korean native cattle (Bos taurus coreanae) at an abattoir in Daejeon Metropolitan City, Republic of Korea. Sarcocysts were detected form 31 specimens (14.8%) and identified as Sarcocystis cruzi via transmission electron microscopy. The wall of S. cruzi has flattened protrusions that did not contain fibrils or microfilaments. The protrusions arose irregularly from the base, contained a fine granular substance, lacked internal microfilaments, and measured approximately 0.21-1.25 µm in length and 0.05-0.07 µm in width. Sequence analysis revealed 99.5% homology to S. cruzi. This is the first report on the prevalence of S. cruzi in native cattle from the Republic of Korea.

Molecular characterisation of Sarcocystis bovifelis, Sarcocystis bovini n. sp., Sarcocystis hirsuta and Sarcocystis cruzi from cattle (Bos taurus) and Sarcocystis sinensis from water buffaloes (Bubalus bubalis).

About 200 individual sarcocysts were excised from 12 samples of cattle beef from five countries (Argentina, Brazil, Germany, New Zealand, Uruguay) and tentatively identified to species or cyst type on the basis of their size and shape and cyst wall morphology. Genomic DNA was extracted from 147 of these sarcocysts and used initially for PCR amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit I gene (cox1) in order to identify the sarcocysts to species and/or sequence type. In addition, seven Sarcocystis sinensis-like sarcocysts collected from the oesophagus of water buffaloes in Egypt were examined at cox1 for comparative purposes. Based on the results from the cox1 marker, selected sarcocyst isolates from both hosts were further characterised at one to three regions of the nuclear ribosomal (r) DNA unit, i.e. the complete 18S rRNA gene, the complete internal transcribed spacer 1 (ITS1) region and the partial 28S rRNA gene. This was done in order to compare the results with previous molecular identifications based on 18S rRNA gene sequences and to evaluate the utility of these regions for species delimitations and phylogenetic inferences. On the basis of sarcocyst morphology and molecular data, primarily the cox1 sequences, four Sarcocystis spp. were identified in the samples of cattle beef. Twenty-two microscopic sarcocysts (1 × 0.1 mm) with hair-like protrusions were assigned to Sarcocystis cruzi, 56 macroscopic sarcocysts (3-8 × 0.5 mm) with finger-like protrusions were assigned to Sarcocystis hirsuta and 45 and 24 microscopic sarcocysts (1-3 × 0.1-0.2 mm) with finger-like protrusions were assigned to Sarcocystis bovifelis and Sarcocystis bovini n. sp., respectively. Sarcocysts of S. cruzi were identified in samples of beef from Argentina and Uruguay; sarcocysts of S. hirsuta in samples from Argentina, Brazil, Germany and New Zealand; sarcocysts of S. bovifelis in samples from Argentina and Germany; and sarcocysts of S. bovini in samples from Argentina and New Zealand. The microscopic sarcocysts from water buffaloes were confirmed to belong to S. sinensis. The cox1 sequences of S. bovifelis and S. bovini, respectively, shared an identity of 93-94 % with each other, and these sequences shared an identity of 89-90 % with cox1 of S. sinensis. In contrast, the intraspecific sequence identity was 98.4-100 % (n = 45), 99.3-100 % (n = 24) and 99.5-100 % (n = 7) for sequences of S. bovifelis, S. bovini and S. sinensis, respectively. In each of the latter three species, an aberrant type of cox1 sequences was also identified, which was only 91-92 % identical with the predominant cox1 type of the same species and about 98 % identical with the aberrant types of the two other species. These aberrant cox1 sequences are believed to represent non-functional nuclear copies of the mitochondrial genes (numts or pseudogenes). They might be used as additional markers to separate the three species from each other. Sequencing of a considerable number of clones of S. bovifelis, S. bovini and S. sinensis from each of the three regions of the rDNA unit revealed intraspecific sequence variation in all loci in all species and particularly in the ITS1 locus (78-100 % identity). As regards the 18S rRNA gene, it was possible to separate the three species from each other on the basis of a few consistent nucleotide differences in the less variable 3' end half of the gene. A comparison of the new sequences with GenBank sequences obtained from S. sinensis-like sarcocysts in cattle in other studies indicated that previous sequences derived from cattle in Germany and Austria belonged to S. bovifelis, whereas those derived from cattle in China belonged to S. bovini. On the basis of the new 28S rRNA sequences, it was possible to separate S. sinensis from S. bovifelis and S. bovini, whereas the latter two species could not be separated from each other. Based on ITS1 sequences, the three species were indistinguishable. Phylogenetic analysis using maximum parsimony placed with fairly high support cox1 sequences of S. bovifelis, S. bovini and S. sinensis, respectively, into three monophyletic clusters, with S. bovifelis and S. bovini being a sister group to S. sinensis. In contrast, phylogenies based on each of the three regions of the rDNA unit did not separate sequences of the three species completely from each other. Characterisation of cox1 of 56 isolates of S. hirsuta from four countries revealed only 13 haplotypes and an intraspecific sequence identity of 99.3-100 %. In the three regions of the rDNA unit, there was more extensive sequence variation, particularly in the ITS1 region. The 22 cox1 sequences of S. cruzi displayed a moderate intraspecific variation (98.6-100 %), whereas there was no variation at the 18S rRNA gene among 10 sequenced isolates. Sequencing of 16 clones of the partial 28S rRNA gene of S. cruzi yielded two markedly different sequence types, having an overall sequence identity of 95-100 %.

Molecular differentiation of Sarcocystis buffalonis and Sarcocystis levinei in water buffaloes (Bubalus bubalis) from Sarcocystis hirsuta and Sarcocystis cruzi in cattle (Bos taurus).

The purpose of the present study was to obtain sarcocysts of Sarcocystis buffalonis and Sarcocystis levinei from water buffaloes and characterize the isolates by molecular methods in order to determine whether the two species were genetically different from Sarcocystis hirsuta and Sarcocystis cruzi, respectively, from cattle, which had been characterized before. About 35 macroscopically visible (3-4 × 1-2 mm) and 20 barely visible (1-3 × 0.2 mm) sarcocysts were excised from the esophagus of 18 naturally infected and freshly slaughtered adult water buffaloes at three slaughterhouses in Egypt. Genomic DNA was extracted from the sarcocysts, and all isolates were first characterized at the mitochondrial cytochrome c oxidase subunit I gene (cox1) gene through PCR amplification and direct sequencing. Selected isolates were subsequently further characterized at the 18S and 28S ribosomal (r) RNA genes and the internal transcribed spacer 1 (ITS1) region of the nuclear rDNA unit by direct sequencing or cloning. Only six of the isolated macroscopic sarcocysts belonged to S. buffalonis, whereas the others belonged to Sarcocystis fusiformis. Twelve of the smaller cysts belonged to S. levinei and seven to Sarcocystis sinensis. The characterization of the sarcocysts of S. sinensis and some of the sarcocysts of S. fusiformis have been reported before. Fifteen additional sarcocyst isolates of S. fusiformis were characterized at cox1 in the present study and found to be identical or closely similar to previous isolates. At cox1, the sequence identity between the six isolates of S. buffalonis was 99.8-100 % (two haplotypes), whereas the identity between the 12 isolates of S. levinei was 99.0-100 % (10 haplotypes). The identity between cox1 sequences of S. buffalonis and S. hirsuta (n = 56) was 92.9-93.6 % (on average 93.4 %), and the identity between cox1 sequences of S. levinei and S. cruzi (n = 22) was 92.9-94.0 % (on average 93.5 %). The phylogenetic analyses placed with high support the cox1 sequences of S. buffalonis and S. hirsuta into two monophyletic sister groups, and the same was true for the cox1 sequences of S. levinei and S. cruzi. Hence, the study established that S. buffalonis and S. levinei are distinct species different from S. hirsuta and S. cruzi, respectively. Nucleotide sequences of S. buffalonis could be distinguished from those of S. hirsuta also at the 28S rRNA gene (clearly different) and the ITS1 region (small and uncertain difference) but not at the 18S rRNA gene. Sequences of S. levinei could be distinguished from those of S. cruzi both at the 18S and 28S rRNA genes (ITS1 region not examined). However, the cox1 gene was superior to the 18S and 28S rRNA genes as regards the ability to unambiguously delimit the species within each species pair, since at the latter markers, the number of consistent nucleotide differences between the species was low and there was a slight overlap between the intraspecific and interspecific sequence divergence. Comparison of the newly generated 18S rRNA gene sequences of S. levinei from water buffaloes with similar sequences deposited in GenBank suggested that S. levinei and S. cruzi are not strictly intermediate host specific but might occasionally infect cattle and water buffaloes, respectively.

Prevalence of Enteric Protozoan Oocysts with Special Reference to Sarcocystis cruzi among Fecal Samples of Diarrheic Immunodeficient Patients in Iran.

The genus Sarcocystis is not usually considered as an important enteric pathogen in immune compromised patients. It might be expected that species for which humans are the final host (Sarcocystis hominis and Sarcocystis suihominis as well as possibly others) would be encountered increasingly often in immunodeficient persons. This study aimed to address how to detect and differentiate Sarcocystis oocysts and/or sporocysts from enteric protozoans in the diarrheal samples of immunodeficient patients in Shiraz, Iran. Diarrheal samples of 741 immunodeficient patients with recurrent persistent or chronic diarrhea were examined by microscopy and molecular biological analysis. Oocysts-positive samples were 68 Cryptosporidium spp., 9 Cystoisospora belli (syn. Isospora belli), 2 Cyclospora cayetanensis, and 15 microsporidia (Enterocytozoon bieneusi). Sarcocystis-like sporocysts found from a woman were identified as Sarcocystis cruzi through 18S rDNA amplification and phylogenetic analysis. To the best of our knowledge, this is the first report of S. cruzi from a human.

RFLP Analysis of Fragments of the 18S rRNA and Cox1 Genes to Identify Sarcocystis cruzi in Water Buffalo (Bubalus bubalis) In Guilan Province, North of Iran.

Background: Sarcocystosis is a zoonotic disease worldwide caused by Sarcocystis spp., some of these species can show clinical and subclinical manifestations, resulting in financial losses. Our study was performed for identifying Sarcocystis sp., in slaughtered buffalo by PCR-RFLP based strategy with sequencing in Guilan, North of Iran. Methods: Overall, 400 fresh muscle samples were prepared via naked-eye observation from 100 buffaloes (esophagus, diaphragm, shoulder, and thigh), followed by the digestion of samples. The PCR was done to amplify partial parts of the 18S rRNA and mitochondrial cytochrome c oxidase subunit I (Cox1) genes. Then, the PCR products were digested by endonuclease SspI, DraI, and FokI. Sequencing of all species was done to confirm the RFLP results. Results: Five macroscopic cysts (1.25%) were visible in the sample by naked-eye examination. Furthermore, 293 samples (73.25%) were found to be Sarcocystis sp. positive through tissue digestion and microscopic observation, whereas 376 samples (94%) were positive by PCR. In addition, the findings of PCR-RFLP and nucleotide sequence samples exhibited the infection of buffaloes with S. cruzi. Conclusion: Based on the data presented herein, Bovine sarcocystosis caused by S. cruzi is very common in buffalo in the Guilan region. Regarding the high prevalence of sarcocystosis, developing disease control and prevention policies for buffaloes is necessary, and a change of attitude in traditional farming is recommended.

Development of a new quantification method of Sarcocystis cruzi through detection of the acetyl-CoA synthetase gene.

Sarcocystis cruzi is a member of the genus Sarcocystis, infecting bovine animals such as cattle and bison as intermediate hosts, and canids such as dogs and raccoon dogs as definitive hosts. Acute sarcocystosis of S. cruzi causes occasional symptoms in cattle, including weight loss, reduced milk production, abortions, and death, and similar to other Sarcocystis species can potentially cause food poisoning in humans when raw or undercooked infected cattle meat is consumed. Despite these issues, genetic information on S. cruzi is scarce, and there is no specific quantitative method for the detection and quantification of the parasite in infected cattle. In this study, we aimed to develop a method based on high-throughput sequencing of S. cruzi genome and transcriptome that specifically and quantitatively detects the S. cruzi acetyl-CoA synthetase gene (ScACS). Cardiac muscles were collected from slaughterhouses in Saitama Prefecture to obtain sarcocysts from which DNA and RNA were extracted for the high-throughput sequencing. Using the sequences, we developed a specific quantitative PCR assay which could distinguish S. cruzi ACS from that of Toxoplasma gondii by taking advantage of the differences in their exon/intron organizations and validated the assay with the microscopic counting of the S. cruzi bradyzoites. Thus, this assay will be useful for future studies of S. cruzi pathogenesis in cattle and for the surveillance of infected animals, thereby easing public health concerns.

Molecular detection of Sarcocystis cruzi in three beef carcases with eosinophilic myositis lesions and in unaffected beef from animals in the same herd.

Eosinophilic myositis in bovine striated muscle thought to be caused by a hypersensitivity reaction to the degradation of Sarcocystis tissue cysts, is a rare reason for carcase condemnation in the United Kingdom. This paper describes the identification of Sarcocystis cruzi associated with lesions of generalised eosinophilic myositis in three English beef carcases, by gross and histopathological examination followed by PCR with subsequent sequencing. Samples from two unaffected animals were also examined. Although sarcocystosis caused by S.cruzi is not considered a public health risk, the clinically affected carcases were deemed unfit for human consumption due to the extensive lesions affecting meat quality. We believe this to be the first report from the UK describing the molecular-based identification of Sarcocystis cruzi in meat affected and unaffected with eosinophilic myositis.

Sarcocystis cruzi in Egyptian slaughtered cattle (Bos taurus): epidemiology, morphology and molecular description of the findings.

Background: Sarcocystis spp. are one of the most common foodborne tissue cyst-forming coccidia with a public health and veterinary concern. Aims: The existing study aimed to rectify the epidemiological profile of Sarcocystis spp. infection in the cattle carcasses as well as to explore the structure and phylogenetic features of Sarcocystis spp. isolates. Methods: A total of 292 cattle carcasses were checked for the existence of sarcocysts using light microscopy (LM) via muscle squash (MS) and peptic digestion (PD) analysis from January 2020 to December 2020. Individual sarcocysts from different cattle tissues were selected for morphologic characterization and DNA extraction. Each sarcocyst's 18S rDNA gene was amplified, sequenced, and analyzed. Results: Overall, 92.5% (270/292) of cattle tissue samples contained microscopic thin walled sarcocysts and were exclusively found in esophagus by light microscopy. A statistically insignificant relationship exists between the prevalence of infection and age groups, gender of cattle, and the seasonal dynamics (P>0.05). Sarcocysts ultrastructural features were completely discussed. Sequencing of 18S rDNA Sarcocystis gene confirmed S. cruzi (identity 99-100%), which was the first molecular identification of the current isolate in the study region. Conclusion: The current survey initially provides a brief account of knowledge about the epidemiology of Sarcocystis spp. infecting cattle and it is considered a starting point for the development of health awareness and efficient preventive schemes for this zoonotic protozoan parasite.

Sarcocystis cruzi infection in free-living European bison (Bison bonasus bonasus L.) from the Bialowieza Forest, Poland - A molecular analysis based on the cox1 gene.

European bison are susceptible to a range of pathogens which may influence their health, and hence, to ensure their protection, it is essential to provide effective monitoring of potential exposure. This study presents the first molecular confirmation of Sarcocystis cruzi infection in European bison based on PCR amplification of the cytochrome c oxidase subunit I (cox1) gene. A sample of heart tissue taken from one fifteen-year-old European bison cow was examined by light microscopy for the presence of heart sarcocysts. The genomic DNA isolated from any identified sarcocysts was subjected to PCR to amplify cox1 gene sequences, and the obtained amplicons were sequenced by Sanger dideoxy sequencing. Two partial cox1 sequences were obtained; they were identified as S. cruzi and deposited in the GenBank™ database under the accession numbers MW490605 and MW490606. BLAST analysis found them to demonstrate the closest similarity to S. levinei (MH255771-MH255779 and KU247874-KU247884), sharing an identity of 93.14-93.8 %. This is the first report to identify sarcocysts isolated from heart tissue of infected European bison living in the Bialowieza forest to species level using cox1 analysis. Our findings confirm that the European bison is a natural intermediate host for S. cruzi. As such, coordinators of future conservation programmes should consider the impact of these diseases on reintroduced animals.

Prevalence and molecular characterization of Sarcocystis infections of retail beef products from central China.

Cattle are the intermediate hosts for five Sarcocystis species including S. hominis and S. heydorni, which also infect humans. To investigate the prevalence of Sarcocystis infections in beef products from 17 cities in the Henan Province of central China, 62 raw beef samples from markets were collected and analyzed for Sarcocystis presence via muscle squashing microscopic observation, histological section examination, and molecular characterization with 18S rRNA gene sequencing. Sarcocystis were detected in a total of 20 of the meat samples. Four species were identified that comprised S. cruzi, S. rommeli, S. heydorni, and S. hirsuta, with S. cruzi as the dominant species. In addition, seven of the 20 infected samples were infected with two or three species. Analysis of the 18S rRNA sequences recovered from these samples suggested very little genetic diversity within each species. This study represents the first molecular identification of Sarcocystis species infection in retail beef products from China. These findings will provide valuable information for evaluating the potential public health risk of bovine Sarcocystis species infections and the control of sarcocystosis in cattle.

Macroscopic, histological, and molecular aspects of Sarcocystis spp. infection in tissues of cattle and sheep / Aspecto Macroscópico, histológico e molecular de Sarcocystis spp. em tecidos de bovinos e ovinos

Abstract The macroscopic, histological, and molecular aspects of Sarcocystis spp. were examined in the tissues of two cattle and four sheep, 16 and eight fragments analyzed respectively, condemned in the slaughterhouse. All 24 samples were collected and analyzed for detecting macrocysts and macroscopic lesions. Subsequently, subdivided for direct examination, polymerase chain reaction and histopathological examination. All sheep tissues samples had grossly white round to oval tissue cysts, ranging from 0.3 to 1 cm in diameter. In contrast, cattle tissues did not present grossly visible cysts but had randomly distributed white-yellow foci with irregular contours. All samples from cattle and sheep had microscopic cysts. In the histological examination of sheep tissues, circular to elongated, encapsulated, basophilic structures ranging from 30 to 3,000 µm in length and 20 to 1,000 µm in width were observed within the skeletal muscle fibers. In cattle tissues, all cardiac muscle four fragments analyzed contained circular to elongated basophilic structures inside cardiomyocytes and in some Purkinje fibers. PCR were performed using the primers: 2L and 3H. In conclusion, all 24 tissues were infected with Sarcocystis spp., and S. gigantea (in sheep) and S. cruzi (in cattle). were the identified species by sequencing.

Resumo Os aspectos macroscópicos, histológicos e moleculares de Sarcocystis spp. foram examinados nos tecidos de dois bovinos e quatro ovinos, 16 e oito fragmentos analisados, respectivamente, condenados no matadouro. Todas as 24 amostras foram coletadas e analisadas para detecção de macrocistos e lesões macroscópicas. Posteriormente, subdivididas para exame direto, reação em cadeia da polimerase e exame histopatológico. Todas as amostras de tecidos de ovelha apresentavam cistos grosseiramente visíveis, caracterizados como brancos, de redondos a ovais e estruturas variando de 0,3 a 1 cm de diâmetro. Em contraste, os tecidos de bovinos não apresentavam cistos grosseiramente visíveis, mas tinham focos branco-amarelos com contornos irregulares, distribuídos aleatoriamente. Todas as amostras de bovinos e ovinos apresentavam cistos microscópicos. No exame histológico de tecidos ovinos foram observadas estruturas basofílicas circulares a alongadas, encapsuladas, variando de 30 a 3.000 µm de comprimento e 20 a 1.000 µm de largura dentro das fibras do músculo esquelético. Nos tecidos de bovinos, todos os quatro fragmentos de músculo cardíaco analisados continham estruturas basofílicas circulares a alongadas, dentro dos cardiomiócitos e em algumas fibras de Purkinje. PCRs foram realizadas utilizando-se os "primers" 2L e 3H. Em conclusão, todos os 24 tecidos estavam infectados com Sarcocystis spp., sendo S. gigantea (em ovinos) e S. cruzi (em bovinos) as espécies identificadas por sequenciamento.

Short communication: Genetic variants of Sarcocystis cruzi in infected Malaysian cattle based on 18S rDNA.

Sarcocystis species are pathogenic parasites that infect a wide range of animals, including cattle. A high prevalence of cattle sarcocystosis has been reported worldwide, but its status is unknown in Malaysia. This study focused on utilizing 18S rDNA to identify Sarcocystis species in Malaysian cattle and to determine their genetic variants. In this study, only Sarcocystis cruzi was detected in Malaysian cattle. The intra-species S. cruzi phylogenetic tree analysis and principal coordinate analysis (PCoA), respectively displayed two minor groups among the parasite isolates. This finding was supported by high Wright FST value (FST=0.647). The definitive hosts (dogs) may play a fundamental role in the development of S. cruzi genetic variants. Additionally, the existence of microheterogeneity within the S. cruzi merozoites and/or distinct genetic variants arisen from independent merozoites in mature sarcocysts, possibly contributed to the existence of intra-species variations within the population.

Sarcocystis cruzi infection in wood bison (Bison bison athabascae).

Endangered wood bison (Bison bison athabascae) is the largest terrestrial mammal in the American continent. Animal health is an important issue in their conservation, and Sarcocystis cruzi may be a cause of clinical disease in Bovidae. Hearts of eight wood bison from Alaska, USA were examined for sarcocysts by histology, transmission electron microscopy, pepsin digestion, and molecularly. Sarcocystis bradyzoites were found in pepsin digests of all eight and sarcocysts were found in histologic sections of myocardium of four bison. Sarcocysts were thin-walled and ultrastructurally consistent with S. cruzi. Characterization of DNA obtained from lysis of pepsin liberated bradyzoites by PCR-RFLP and subsequent phylogenetic analyses matched with that previously reported for S. cruzi infecting cattle in the USA. Collectively, data indicate that wood bison is a natural intermediate host for S. cruzi.

Sarcocystis cruzi: First Molecular Identification from Cattle in Iran.

Sarcocystis is a genus of cyst-forming parasites infecting both animals and human. This study aimed to isolate coccidian tissue cysts from muscle of infected animals by a simple method in addition to molecular identification of Sarcocystis cruzi from the samples. The samples were obtained from commercial source in Babol, Northern Iran. Five grams of calf muscle was cut into 2-3 pieces in 30 ml of phosphate-buffered saline containing 0.1% Tween 80 and homogenized with IKA T25, DIGITAL ULTRA-TURRAX. The homogenate was filtrated twice and used for microscopy examination and molecular analysis. Polymerase chain reaction (PCR) and partial sequence analysis of the 18S ribosomal gene were used to identify the Sarcocystis species. Giemsa stain of the filtrated calf muscle samples showed that the sample had ellipse to around tissue cysts contained crescent-shaped bodies. The PCR of the 18SrDNA yielded an 1100 bp DNA band on agarose gel and sequence analysis of the DNA confirmed the isolate as S. cruzi. The sequence was deposited in GenBank by Accession No.KC508514. This is the first molecular identification of an isolate of S. cruzi in Iran.

Sarcocystis cruzi (Apicomplexa: Sarcocystidae) no cachorro-do-mato (Cerdocyon thous) / Sarcocystis cruzi (Apicomplexa: Sarcocystidae) in the crab-eating fox (Cerdocyon thous)

Esporocistos de Sarcocystis foram identificados nas amostras fecais de um cachorro-do-mato. Eles foram dados por via oral para um bezerro em aleitamento, sendo observados cistos com morfologia compatível com os de Sarcocystis cruzi na musculatura cardíaca e esquelética, três meses após a infecção. Musculatura cardíaca deste bezerro foi dada para um segundo cão doméstico livre de coccídios, que eliminou esporocistos compatíveis com os de Sarcocystis em suas fezes, tendo com períodos pré-patente e patente 11 e 12 dias após a infecção respectivamente. Para comparar a morfologia dos esporocistos e cistos, um segundo cão, também livre de coccídios, foi alimentado com musculatura cardíaca de um bovino infectando naturalmente e positivo para cistos de S. cruzi. Esporocistos compatíveis com os eliminados pelo primeiro cão foram encontrados nas fezes. Apesar dos esporocistos eliminados pelo cachorro-do-mato serem significativamente diferentes dos eliminados pelos cães infectados experimentalmente, pode se considerar com base na morfologia dos esporocistos, cistos e na transmissão biológica que a espécie encontrada nas fezes do cachorro-do-mato é Sarcocystis cruzi.

Sporocysts of Sarcocystis were identified in feces samples of a crab-eating fox, and were orally given to a suckling calf; after 3 months of infection, sarcocysts morphologically similar to Sarcocystis cruzi were observed in cardiac and skeletal striated muscles. The cardiac muscles of this calf were orally given to a puppy free of coccidia, that shed sporocysts in its feces.with a prepatent and patent period of 11 and 12 days after infection, respectively. To compare the morphology of the sporocysts and cysts, a second puppy was fed on bovine cardiac muscles infected naturally, and sporocysts identical to those shed by the first dog were recovered from its feces. In spite of the significant difference between sporocysts found in the mucosa of the crab-eating fox and those shed by the first and second puppies, the species observed in this study was considered to be Sarcocystis cruzi, based on size of the sporocyts, morphology of the cyst wall, and the pray-predator cycle.