Morphological and molecular characterization of Sarcocystis spp. in pigs (Sus scrofa domestica) from Argentina

Sarcocystis spp. are intracellular protozoan parasites with an obligatory heteroxenous life cycle. The objective of this study was to identify Sarcocystis spp. in pig muscles from Argentina, by light and transmission electron microscopy (TEM), and molecular studies. Muscles samples from 561 pigs (Sus scrofa domestica) were classified according to the breeding system in: intensive farming (IF, n = 295; animals kept in confinement during most of their productive cycle), or semi-extensive farming (SEF, n = 266; animals bred outdoors, generally family or backyard production). Results showed that 24.8% (139/561) were positive by light microscopy, with a significantly higher prevalence in the SEF (34.6%; 92/266) than the IF pigs (15.9%; 47/295) (p < 0.05). Of the 202 samples analyzed by PCR, 96 were positive (47.5%) for the 18S rRNA (18S ribosomal RNA) fragment. All samples analyzed by the S. suihominis specific coxI (mitochondrial cytochrome c oxidase subunit I) PCR (n = 235; 96 positives by 18S rRNA PCR and 139 positives by light microscopy) were negative. Fourteen individual cysts were positive for the 18S rRNA PCR and sequenced. Consensus sequences obtained from the 18S rRNA fragment PCR ranged from 613 to 880 bp and showed 100% of identity between them and with previously reported S. miescheriana sequences. In all the pig samples analyzed by TEM, cyst wall ultrastructure was compatible with S. miescheriana. This is the first study that provides infection rates and describes and identifies morphological and molecular features of Sarcocystis spp. cysts in pigs from Argentina.

A cyst-forming coccidian with large geographical range infecting forest and commensal rodents: Sarcocystis muricoelognathis sp. nov

BACKGROUND

The geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known.

METHODS

Experimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China.

RESULTS

We identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystis zuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystis attenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low's squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews.

CONCLUSIONS

Our results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations.

First molecular detection of Sarcocystis suihominis in a domestic pig of Nigeria

Sarcocystis are Apicomplexan protozoa with a dixenous life cycle that includes a predator and a prey as definitive and intermediate hosts, respectively. Domestic and wild pigs are intermediate hosts of S. suihominis, with formation of sarcocysts in their muscles, while humans and non-human primates act as final hosts. After ingesting raw or undercooked sarcocyst-infested pork, signs of gastroenteritis including inappetence, nausea, vomiting, and diarrhea may develop in humans. Moreover, excretion of infective forms with human feces leads to dissemination of the parasite in the environment. In this study, macroscopic sarcocysts of white color, oval shape, and a diameter of approximately 3-8 mm were found in the skeletal muscle of a slaughtered domestic pig (Sus scrofa domesticus) destined for human consumption in an abattoir of Makurdi, Benue State, Nigeria. Sarcocyst DNA was used as template to PCR amplify the near-complete length of the 18S rRNA gene and a fragment of the cytochrome c oxidase subunit 1 (cox-1) gene. Amplicons were sequenced and used to construct phylogenetic trees with selected available Sarcocystis spp. sequences. In both cases, the placement of the analyzed sequences with S. suihominis was strongly supported, confirming the species identity of this macroscopic sarcocyst-forming parasite. This constitutes the first molecular identification of S. suihominis in Nigeria and the African continent. Proximity between pigs and humans, and poor sanitary conditions frequently encountered in pig farms of Nigeria might favor the dissemination of this zoonotic parasite, posing a threat to public health.

Experimental Evidence of the Diarrheal Activity of Sarcocystis sp. in Sika Deer (Cervus nippon)

Recently, the wild deer population has been increasing in Japan, causing serious feeding-related damage to the agricultural and forestry industries. In conjunction with the government's promotion of hunting for population control, the effective utilization of resources and promotion of the game meat industry as a sixth sector of industrialization are desired by local governments. However, several cases in which patients showed intestinal symptoms such as diarrhea due to the consumption of sika deer meat infected with protozoan Sarcocystis spp. have been reported, and the pathogenic microorganisms found in wild deer should be investigated. In this study, Sarcocystis sp. parasitized Kyushu sika deer (Cervus nippon nippon) in Nagasaki Prefecture, Japan, was examined for its enterotoxicity. A phylogenetic analysis based on the sequence of the 18S rRNA gene and cox1 showed that the species was highly homologous to Sarcocystis japonica and/or Sarcocystis sp. HM050622. We attempted to confirm the diarrhea-evoking toxicity of Sarcocystis sp. in sika deer meat, which has been previously reported in human case reports. A mouse ileal loop assay showed that Sarcocystis sp. in sika deer meat induced significant fluid accumulation in the loop at doses of ∼5 × 106 bradyzoites. Western blotting showed that these Sarcocystis parasites possess actin-depolymerizing factor, a diarrhea-evoking factor, similar to Sarcocystis fayeri, which exists in horsemeat. However, the pathogenic conditions of the ileal loop were different from those of similar experiments with S. fayeri. This study suggests that S. japonica parasitizing C. n. nippon may cause diarrhea via a different mechanism from that of S. fayeri.

Prevalence and distribution pattern of Sarcocystis spp. in slaughtered cattle from the Peruvian tropical Andes, Peru

This study aimed to estimate the prevalence and distribution patterns of Sarcocystis spp. in cattle tissues in Chachapoyas province in the Peruvian tropical Andes. Additionally, the risk factors associated with the prevalence and the correlation of two diagnostic techniques (direct microscopy of squashed fresh muscle tissues and histopathology) were explored. The tongue, heart, esophagus, Latissimus dorsi muscle, and diaphragm of 210 animals slaughtered in the municipal slaughterhouse of Chachapoyas were evaluated by both techniques. Macroscopic sarcocysts were detected in 16.7% of tissues (CI 95% 11.7-21.7%). The total prevalence of Sarcocystis spp. was 96.2% (95% CI 93.6-98.8%) by direct light microscopy and 100% by histopathology. The highest Sarcocystis prevalence was detected in the esophagus. No significant statistical differences were found in the prevalence of Sarcocystis related to sex, age, or provenance. Both techniques demonstrated a very weak Kappa correlation (κ ≤ 0.24) in predicting the presence of the parasite in each of the five evaluated muscles. Direct microscopy can be implemented at slaughterhouses as a rapid screening test, but it is essential to confirm by histopathology the absence of the parasite in direct-microscopy-negative samples. It is also recommended that beef from the Peruvian Andes be thoroughly cooked for both human and animal consumption because of the zoonotic potential of some species of Sarcocystis.

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.

The same genotype of Sarcocystis neurona responsible for mass mortality in marine mammals induced a clinical outbreak in raccoons (Procyon lotor) 10 years later

Here, we report the first known outbreak of clinical protozoal myeloencephalitis in naturally infected raccoons by the parasite Sarcocystis neurona. The North American opossum (Didelphis virginiana) and the South American opossum (Didelphis albiventris) are its known definitive hosts. Several other animal species are its intermediate or aberrant hosts. The raccoon (Procyon lotor) is considered the most important intermediate host for S. neurona in the USA. More than 50% of raccoons in the USA have sarcocysts in their muscles, however clinical sarcocystosis in raccoons is rare. In 2014, 38 free-living raccoons were found dead or moribund on the grounds of the Saint Louis Zoo, Missouri, USA. Moribund individuals were weak, lethargic, and mildly ataxic; several with oculo-nasal discharge. Seven raccoons were found dead and 31 were humanely euthanized. Postmortem examinations were conducted on nine raccoons. Neural lesions compatible with acute sarcocystosis were detected in eight raccoons. The predominant lesions were meningoencephalitis and perivascular mononuclear cells. Histologic evidence for the Canine Distemper Virus was found in one raccoon. Schizonts and merozoites were present in the encephalitic lesions of four raccoons. Mature sarcocysts were present within myocytes of five raccoons. In six raccoons, S. neurona schizonts and merozoites were confirmed by immunohistochemical staining with S. neurona-specific polyclonal antibodies. Viable S. neurona was isolated from the brains of two raccoons by bioassay in interferon gamma gene knockout mice and in cell cultures seeded directly with raccoon brain homogenate. Molecular characterization was based on raccoon no. 68. Molecular characterization based on multi-locus typing at five surface antigens (SnSAG1-5-6, SnSAG3 and SnSAG4) and the ITS-1 marker within the ssrRNA locus, using DNA isolated from bradyzoites released from sarcocysts in a naturally infected raccoon (no. 68), confirmed the presence of S. neurona antigen type I, the same genotype that caused a mass mortality event in which 40 southern sea otters stranded dead or dying within a 3 week period in April 2004 with S. neurona-associated disease. An expanded set of genotyping markers was next applied. This study reports the following new genotyping markers at 18S rRNA, 28S rRNA, COX1, ITS-1, RON1, RON2, GAPDH1, ROP20, SAG2, SnSRS21 and TUBA1 markers. The identity of Sarcocystis spp. infecting raccoons is discussed.

Molecular differentiation of Sarcocystis miescheriana and Sarcocystis suihominis using a new multiplex PCR targeting the mtDNA cox1 gene in wild boars in southern Italy

The increase of wild boar populations density and their meat consumption across Europe could expose humans to a plethora of foodborne diseases as sarcocystosis, caused by the zoonotic protozoan Sarcocystis suihominis. Humans become infected by eating raw or undercooked pig (Sus scrofa domesticus) containing S. suihominis sarcocysts. Despite this, to date very few data are available on the risk of infection by this parasite to wild boar (Sus scrofa) meat consumers. Thus, the present study aimed to assess the occurrence of Sarcocystis spp. in wild boars from southern Italy, applying both histology and a new multiplex PCR assay targeting the cox1 gene. Between 2019 and 2020, 997 muscle tissues (i.e., n = 269 oesophagus, n = 277 diaphragms, n = 298 hearts, n = 153 tongues) from 311 wild boars were collected and screened by a combined histological and molecular approach. Overall, 251 (80.7%) animals tested were positive for Sarcocystis spp., and S. miescheriana whose definitive hosts are canids, was the only molecularly identified species. A statistically significant difference (p < 0.05) in the prevalence of Sarcocystis infection was found according to the wild boar age and muscle tissue. Findings outlined the low zoonotic potential of infection to humans via wild boar meat consumption in Italy and the importance of the application of new molecular methods in distinguishing different Sarcocystis species.

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 99–100% 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.

Epidemiological risk factors and phylogenetic affinities of Sarcocystis infecting village chickens and pigs in Peninsular Malaysia

The intake of food and water containing the Sarcocystis parasite has been linked to a number of outbreaks worldwide, including Malaysia. Nevertheless, the lack of surveys and epidemiological data on Sarcocystis infections in Malaysia makes it difficult to estimate its occurrence in humans and animals. A cross-sectional study was conducted to determine the prevalence of Sarcocystis and the risk factors associated with infection among village chickens and pigs reared under different farm managements in Peninsular Malaysia. Phylogenetic trees were constructed using partial fragments of the 18S rRNA gene and ITS1 sequences. In the present study, 680 sera samples were collected from village chickens (n=250) and commercial pigs (n=433) and anti-Sarcocystis antibodies were screened using the enzymelinked immunosorbent assays (ELISA) kit. At the animal level, the prevalence of Sarcocystis was 9.2% (95% CI: 5.92-13.48) and at the farm level, it was 64.0% (95% CI: 42.52-82.03) in village chickens. The animal-level seroprevalence of Sarcocystis for pigs was 3.7% (95% CI: 2.13-5.93) and 36.8% (95% CI: 16.29-61.64) at the farm-level. Polymerase Chain Reaction (PCR) was conducted on meat samples from various parts of village chickens (n=250) consisting of brain, heart, lung, and pectoralis muscle tissues, and pork (n=121) consisting of intercostal muscle, diaphragm, and tongue. Sarcocystis DNA was detected in 6.4% (95% CI: 4.60-11.60) of village chicken samples but zero in pork samples. A total of 11 unique Sarcocystis haplotypes were isolated from these tissue samples. Multivariable logistic regression analysis of the putative risk factors showed a statistically significant association between Sarcocystis infection in pigs and uncovered storage of feed. Although no zoonotic Sarcocystis was isolated in this study, we reported the first discovery of S. wenzeli in Malaysia.

Molecular identification and phylogenetic confirmation of Sarcocystis species in slaughtered camels in Al-Najif province, Iraq

Background

Sarcocystis is an intracellular parasite of particular importance as it infects many domestic animals as camels that play the role of intermediate host for the parasite.

Aim

This study aimed to identify Sarcocystis species in camels by molecular assay with confirmation of local isolates by phylogenetic analysis.

Methods

A total of 200 slaughtered camels (Camelus dromedarius) that were slaughtered in Al-Najaf province (Iraq) abattoirs from October (2021) to July (2022) were subjected to collect the fresh tissues from four organs (esophagus, diaphragm, skeletal muscle, and heart), to be tested later by the conventional polymerase chain reaction (PCR). Then, a total of 20 positive genomic DNA samples were sequenced, named, got specific access numbers (OP785703.1 to OP785722.1), and compared with the NCBI-GenBank isolates.

Results

Targeting Cox1 gene, 80% of collected tissues were found positive by the conventional PCR assay. Phylogenetic tree analysis revealed that the local Sarcocystis isolates were identical to Indian S. cameli isolates at 99.70%-99.90%. Significantly, an increase in Sarcocystis infection was seen in the esophagus compared to the diaphragm, skeletal muscle, and heart; older (>4 years) than younger (≤4 years) camels, and in females more than males.

Conclusion

To the best of our knowledge, this represents the first molecular study in Iraq that identifies Sarcocystis cameli in camels. However, additional epidemiological and molecular studies in camel populations as well as in other domestic and wild animals appeared to be necessary.

Molecular detection of Toxoplasma gondii, Neospora caninum and Sarcocystis spp in tissues of Sus scrofa slaughtered in southern Brazil

The aim of this study was to determine the presence of deoxyribonucleic acid (DNA) from Toxoplasma gondii, Sarcocystis spp. and Neospora caninum, in tissues of wild boars slaughtered in southern Brazil. A total of 156 samples were collected from different organs of 25 wild boars, and DNA from at least one of the protozoa investigated was detected in 79 samples. To differentiate between infectious agents, restriction fragment length polymorphism was performed using the restriction enzymes DdeI and HpaII. For N. caninum, conventional PCR was performed with specific primers. The DNA of at least one of the studied pathogens was detected in each animal: 26.58% for T. gondii, 68.36% for Sarcocystis spp. and 5.06% for N. caninum. Coinfection between T. gondii and Sarcocystis spp. occurred in 14 animals, between T. gondii and N. caninum in only one male animal, between Sarcocystis spp. and N. caninum in a female, while co-infection with the three agents was equally observed in only one male animal. Considering the high frequency of detection and its zoonotic risk, especially T. gondii, it appears that wild boars can be potential sources of transmission of infectious agents and the adoption of monitoring measures in these populations should be prioritized.

Microscopic Detection of Intestinal Sarcocystis Infection Diagnosed in International Travelers at the Institute of Tropical Medicine, Antwerp, Belgium, from 2001 to 2020

Although a stay in tropical regions is considered a risk factor for acquiring Sarcocystis infection, to date intestinal sarcocystosis has never been described in returning travelers. We did a retrospective cross-sectional study, retrieving all Sarcocystis spp. microscopy-positive stool results of individuals who attended the travel clinic of the Institute of Tropical Medicine, Antwerp in the period from 2001 to 2020. We reviewed the medical records and report on the epidemiology and clinical features of intestinal sarcocystosis in international travelers. In 57 (0.09%) of 60,006 stool samples, oocysts or sporocysts of Sarcocystis spp. were found, often together with other intestinal infections. Twenty-two (37%) individuals were asymptomatic, 17 (30%) had intestinal ± extraintestinal symptoms, and 18 (32%) had extraintestinal symptoms only. Only one traveler had symptoms suggestive of acute gastrointestinal sarcocystosis without an alternative diagnosis. Intestinal Sarcocystis infection predominated in male travelers. At least 10 travelers most likely acquired intestinal Sarcocystis in Africa, where it was never described before. In a national reference travel clinic in Europe, the presence of intestinal Sarcocystis oocysts is a rare finding, predominant in male travelers. Infection with this parasite infrequently leads to suggestive clinical manifestations such as acute gastrointestinal symptoms. Our data strongly suggest that Sarcocystis can be acquired throughout tropical areas, including Africa.

Identification of Sarcocystis spp. in wild boars (Sus scrofa) from Argentina

Sarcocystis spp. are intracellular protozoan parasites with an obligatory heteroxenous life cycle. The objective of this study is to identify Sarcocystis spp. in wild boar muscles from Argentina by light and transmission electron microscopy and molecular characterization. Muscle samples from diaphragm, tongue, masseter, intercostals, heart, and forelimbs of 240 wild boars were analyzed. Of the animals, 48.3% (116/240) were positive for sarcocysts by light microscopy, whereas 45.8% (110/240) were positive for Sarcocystis spp. by PCR targeting 18S rRNA fragment. These samples were subjected to a specific PCR for S. suihominis coxI gene, 3.6% (4/110) of which were weak positives. Unfortunately, sequence analysis was inconclusive. This could be related to a potentially low S. suihominis cyst load in the samples, or to an incomplete primer matching with the South American S. suihominis sequences. Seventeen individual sarcocysts were positive by PCR for the 18S rRNA fragment, whose sequences showed 99.75-100% identity with each other and with previously reported S. miescheriana sequences. A total of 21 cysts collected from 11 muscle samples and analyzed by TEM presented a cyst wall type compatible with S. miescheriana, and one cyst presented an ultrastructure compatible with S. suihominis. The latter came from a sample that also contained S. miescheriana cysts, indicating that the animal was co-infected. This is the first study that provides infection rates and describes and identifies morphological and molecular features of Sarcocystis spp. cysts in wild boars from South America.

Redescription, deposition of life-cycle stage specimens of Sarcocystis bovifelis Heydorn, Gestrich, Mehlhorn and Rommel, 1975, and amendment to Sarcocystis hirsuta Moulé, 1888

There is considerable debate concerning the life cycles and taxonomy of Sarcocystis species in cattle. Of the 8 species of Sarcocystis named from cattle, 2 (Sarcocystis cruzi and Sarcocystis heydorni) are morphologically distinctive because their sarcocysts are microscopic and the sarcocyst wall is thin (<0.5 μm thick). The sarcocysts of the remaining species (Sarcocystis hirsuta, Sarcocystis hominis, Sarcocystis bovini, Sarcocystis bovifelis, Sarcocystis sinensis, Sarcocystis rommeli) have thick (5–8 μm) walls indistinguishable by light microscopy, alone. To provide needed clarity, I herein review the history, nomenclature and life cycle of S. bovifelis (originally named by Heydorn and associates from Germany), redescribe it and deposit specimens of its various life-cycle stages at a museum for future reference. I also provide means to distinguish this parasite from S. hirsuta. Cats are the definitive hosts for both S. bovifelis and S. hirsuta. The sarcocysts of S. bovifelis are microscopic, its sarcocyst wall is type 10g, it has 2 schizogonic stages in blood vessels and sarcocysts are formed between 25 and 30 days post-inoculation in striated muscles, but not in the heart. Sporulated oocysts are 17.1 × 12.7 μm and sporocysts are 12.8 × 8.4 μm. The sarcocysts of Sarcocystis hirsuta are macroscopic, up to 7 mm long, its wall is type 18. Nothing is known of the development of S. hirsuta in cattle tissues and in cat intestine. Size of its oocysts and sporocysts is uncertain.

Molecular Epidemiology, Species Distribution, and Zoonotic Importance of the Neglected Meat-Borne Pathogen Sarcocystis spp. in Cattle (Bos taurus): A Global Systematic Review and Meta-analysis

BACKGROUND

Sarcocystis species are diverse apicomplexan parasites, though only two zoonotic species (S. hominis and S. heydorni) circulate between cattle and humans. Due to the importance of cattle in the human food chain and to prevent the consequences of parasitosis in humans, the first global systematic review and meta-analysis on molecular epidemiology, species distribution, and zoonotic significance of Sarcocystis infection in cattle was performed.

METHODS

For this aim, four international English databases (PubMed, Scopus, Google Scholar, and Web of Science) were systematically searched till 20th September 2021, and random-effect models were drawn to calculate total estimates and their 95% confidence intervals (CIs).

RESULTS

Finally, 44 papers from 21 countries were qualified for this review which examined 8526 cattle regarding Sarcocystis infection, rendering a total prevalence of 62.7% (95% CI 53-71.5%). Globally, 12 Sarcocystis spp. have been reported from cattle, including S. cruzi, S. hominis, S. hirsuta, S. rommeli, S. heydorni, S. bovifelis, S. bovini, S. sinensis, S. gigantea, S. fusiformis, S. hjorti and S. tenella. Among them, S. cruzi (37 studies), S. hominis (22 studies) and S. hirsuta (19 studies) were the 3 most common species, with 76.4% (95% CI 64.8-85%), 30.2% (95% CI 19.3-44%) and 8.7% (95% CI 3.8-18.6%), respectively. However, molecular identification was not performed in 48.4% (95% CI 27.3-70.1%) of the positive samples.

CONCLUSION

Despite the zoonotic significance of Sarcocystis spp., particularly S. hominis, the epidemiology and distribution of Sarcocystis infection in cattle remains unclear and demands more extensive researches around the world.

Molecular identification of Sarcocystis species in diaphragm muscle tissue of European mouflon (Ovis gmelini musimon) from Austria

Previous morphological studies suggested that mouflon may have sarcocysts similar to those of sheep. However, to date, no molecular-based studies of the species of Sarcocystis infecting mouflon have been done. The present study identified Sarcocystis species in diaphragm muscle samples from 20 European mouflon (Ovis gmelini musimon). Molecular identification using the cox1 sequence analysis was performed on sarcocysts excised from muscle tissue and on DNA from digested muscle samples. Both frequency and intensity of infection in mouflon were high with 19 of 20 animals testing Sarcocystis positive and > 50 cysts per gram of tissue recovered from 10 of the 19 Sarcocystis positive animals. Molecular analysis revealed dominant Sarcocystis tenella (18/19 animals) and Sarcocystis arieticanis (1/19 animals), whose known intermediate hosts are sheep. In addition, Sarcocystis capracanis, which is known to form sarcocysts in goats, was detected in two animals. The results of this study demonstrated the digestion method to be superior over the direct isolation of sarcocysts for the molecular identification of Sarcocystis species in a certain host. Future research of Sarcocystis diversity in wild ovine and caprine species is needed.

Sarcocystis species in bovine carcasses from a Belgian abattoir: a cross-sectional study

BACKGROUND

Sarcocystis species are obligatorily heteroxenous parasites, of which some are zoonotic, representing a public health and economic impact. This study investigated the occurrence of Sarcocystis spp. in cattle sampled from a Belgian slaughterhouse.

METHODS

A total of 200 carcasses were included in the study, sampled during 10 sampling days. The sedimentation method was applied to isolate the sarcocysts from both heart and diaphragm muscles collected from each carcass. Multiplex PCR, PCR-RFLP as well as cox1 gene sequencing techniques were applied serially on collected sarcocysts for species identification.

RESULTS

Sarcocystis spp. were detected in 64% (128/200; 95% CI 57-71%) of the sampled carcasses. Female dairy cattle presented the highest Sarcocystis occurrence rate (91%) as well as the highest Sarcocystis species diversity compared to female beef and male beef. Sarcocystis spp. were detected more often in the heart muscles than in the diaphragm among female beef (p < 0.001) and dairy carcasses (p = 0.001), while in male carcasses no significant difference was observed (p = 0.763). The effect of age was not significant in male carcasses (p = 0.872), while the odds of finding sarcocysts significantly increased with age (p = 0.003) within both types of female carcasses. S. cruzi was the most prevalent species and was found in 56.5% (113/200) of the carcasses, followed by S. hominis (21.0%, 42/200), S. bovifelis (12.5%, 25/200), S. bovini (2.0%, 4/200), S. hirsuta (1.5%, 3/200) and S. heydorni (0.5%, 1/200). Six different species were detected in the diaphragm, while only two species were recovered from the heart. S. cruzi was the most prevalent species in heart, while in the diaphragm, this was S. hominis.

CONCLUSIONS

The detection of S. hominis in 21% of the sampled carcasses presents a potential food safety issue, and further research is warranted into controlling this infection.

Sarcocystis neurona Transmission from Opossums to Marine Mammals in the Pacific Northwest

Increasing reports of marine mammal deaths have been attributed to the parasite Sarcocystis neurona. Infected opossums, the only known definitive hosts, shed S. neurona sporocysts in their feces. Sporocysts can contaminate the marine environment via overland runoff, and subsequent ingestion by marine mammals can lead to fatal encephalitis. Our aim was to determine the prevalence of S. neurona in opossums from coastal areas of Washington State (USA) and to compare genetic markers between S. neurona in opossums and marine mammals. Thirty-two road-kill opossums and tissue samples from 30 stranded marine mammals meeting inclusion criteria were included in analyses. Three opossums (9.4%) and twelve marine mammals (40%) were confirmed positive for S. neurona via DNA amplification at the ITS1 locus. Genetic identity at microsatellites (sn3, sn7, sn9) and the snSAG3 gene of S. neurona was demonstrated among one harbor porpoise and two opossums. Watershed mapping further demonstrated plausible sporocyst transport pathways from one of these opossums to the location where an infected harbor porpoise carcass was recovered. Our results provide the first reported link between S. neurona genotypes on land and sea in the Pacific Northwest, and further demonstrate how terrestrial pathogen pollution can impact the health of marine wildlife.

Genetic characterization and phylogenetic analysis of Sarcocystis suihominis infecting domestic pigs (Sus scrofa) in India

A total of 57 tissue samples of domestic pigs (Sus scrofa) were collected from the meat outlets of five north Indian states and examined for sarcocystosis by histological and molecular methods. The genomic DNA extracted from five representative positive isolates was subjected to PCR amplification of the partial 18S rRNA gene followed by cloning and sequencing. Sequence analysis of the newly generated Indian isolates recorded 96.9-100.0% identity with published sequences of Sarcocystis suihominis. Two new haplotypes that have not been previously described manifested 99.5-100.0% nucleotide homology within themselves. In the phylogenetic analysis, Indian isolates of S. suihominis grouped together with S. suihominis originating from Italy, and they collectively formed a sister clade with Sarcocystis miescheriana within a clade containing various Sarcocystis spp. of ruminants having felids as final hosts. At the same time, this clade separated from a sister clade containing Sarcocystis spp. of bovid or cervid ruminants using canids as known or surmised definitive host. The current study established the phylogenetic relationship of Indian isolates of S. suihominis with various Sarcocystis spp. as well as with other taxa of Sarcocystidae family based on 18S rRNA gene for the first time.

Morphological and molecular characterizations of Sarcocystis miescheriana and Sarcocystis suihominis in domestic pigs (Sus scrofa) in China

In this study, 36.8% (28/76) of tissue samples collected from domestic pigs (Sus scrofa) contained sarcocysts, as determined by light microscopy. The organisms were identified as Sarcocystis miescheriana and Sarcocystis suihominis based on their morphological and molecular characteristics. Four genetic markers, i.e., 18S rDNA, 28S rDNA, ITS-1 region (ITS-1), and the mitochondrial COX1 gene (COX1), of the two parasites were sequenced and analyzed, and the 28S rDNA and ITS-1 of S. suihominis obtained from pigs constituted the first records of these markers in GenBank. The sequences of the four loci (18S rDNA, 28S rDNA, ITS-1, and COX1) of S. miescheriana shared high identities with those of S. miescheriana obtained from domestic and/or wild pigs in GenBank, with similarities of 99.6%, 99.6%, 95.9%, and 95.4%, respectively. The 18S rDNA sequences of S. suihominis exhibited 99.4% identity with those of S. suihominis from domestic and wild pigs. The comparison of the newly obtained sequences of the four genetic markers between the two parasites revealed that the interspecific similarities of 18S rDNA, 28S rDNA, ITS-1, and COX1 were 97.7%, 96.6%, 80.3%, and 81.2%, respectively. Therefore, the two species could be better discriminated with ITS-1 and mitochondrial COX1 compared with 18S rDNA or 28S rDNA. The phylogenetic analysis using 28S rDNA indicated that the two Sarcocystis species in domestic pigs had a close relationship.

Sarcocystis morae (Apicomplexa) in Fallow Deer (Dama dama) from Spain: Ultrastructure and New Host Record

Members of the genus Sarcocystis are frequently found infecting members of the family Cervidae. Although Sarcocystis species are generally host specific for their intermediate hosts, species in cervids appear to be less host specific. Here, we report fallow deer (Dama dama) as a new host for Sarcocystis morae, originally described from the red deer (Cervus elaphus). Tongues of 69 legally hunted animals in Spain were tested for sarcocysts, and the species were characterized by light microscopy, ultrastructurally and molecularly. Sarcocysts were identified in 66.7% of D. dama. Sarcocysts had thin (<2 μm thick) cyst wall with hair-like villar protrusions bifurcated at their tips resembling type 8a. Genetic sequences obtained for 18S rRNA and COI reached 99.6-100% and 97.9-98.7% similarity, respectively, to those of S. morae from the red deer. The present study provides new data concerning lower level of host specificity within Sarcocystis genus for cervids.

Morphological and molecular description of Sarcocystis ratti n. sp. from the black rat (Rattus rattus) in Latvia

Rodents have been widely studied as intermediate hosts of Sarcocystis; however, only a few reports on these parasites in the black rat (Rattus rattus) are known. Having examined 13 black rats captured in Latvia, sarcocysts were found in skeletal muscles of two mammals and were described as Sarcocystis ratti n. sp. Under a light microscope, sarcocysts were ribbon-shaped, 0.9-1.3 × 0.09-0.14 mm in size and had a thin (0.8-1.3 μm) and smooth cyst wall. The lancet-shaped bradyzoites were 8.3 × 4.3 (7.5-9.3 × 3.9-4.8) μm. Under a transmission electron microscope, the cyst wall was up to 1.3 μm thick, wavy, the ground substance appeared smooth, type 1a-like. Morphologically, sarcocysts of S. ratti were somewhat similar to those of S. cymruensis, S. rodentifelis, and S. dispersa-like previously identified in the brown rat (Rattus norvegicus). On the basis of 18S rDNA, 28S rDNA, and cox1, significant genetic differences (at least 2.3, 4.5, and 5.8%, respectively) were observed when comparing S. ratti with other Sarcocystis species using rodents as intermediate hosts. While ITS1 sequences of S. ratti were highly distinct from other Sarcocystis species available in GenBank. Phylogenetic and ecological data suggest that predatory mammals living near households are definitive hosts of S. ratti.

Prevalence of Sarcocysts in the Muscles of Raptors from a Rehabilitation Center in North Carolina

The life cycle of Sarcocystis species is heteroxenous (2-host), with carnivores being the definitive host and herbivores serving as intermediate hosts in predator-prey relationships. Raptors (eagles, hawks, falcons, and owls) are apex predators and are not consumed routinely by other carnivores, making the occurrence of sarcocysts in their muscles unusual. Recent reports of sarcocysts in eagles and owls with Sarcocystis encephalitis suggests that this condition may be becoming more frequent, and Sarcocystis falcatula has been implicated as the agent of encephalitis in golden ( Aquila chrysaetos) and bald eagles ( Haliaeetus leucocephalus) as well as great horned owls ( Bubo virginianus). The present study was done to determine the prevalence of sarcocysts of Sarcocystis species in the muscles of raptors from the southeastern United States. Pectoral and heart muscle from 204 raptor patients from the Carolina Raptor Center, Huntersville, North Carolina were tested for the presence of Sarcocystis species using histology. Only a few sarcocysts were seen in sections of pectoral muscle from 39 of 204 raptors (19.1%) and heart muscle from 9 that also had sarcocysts in their pectoral muscle. Two structural types of sarcocysts, thin-walled (1 μm; 62%) or thick-walled (>2 μm, 38%), were seen. Statistical analysis of raptor age and gender was done by Fisher's exact test on samples from raptors with 20 or more samples per group. The prevalence of sarcocysts by age (2 yr or more) was significant for red-shouldered hawks ( Buteo lineatus) ( P = 0.022) and Cooper's hawks ( Accipiter cooperii) ( P = 0.028). Sarcocyst prevalence in male raptors from these groups evaluated statistically were always less than in females. Prevalence in female red-tailed hawks ( Buteo jamaicensis) (42.1%) was significantly greater than in males (6.7%) using Fisher's exact test ( P = 0.047). Examination of case histories from the 39 sarcocyst-positive raptors did not reveal an association with sarcocysts in raptor pectoral or heart muscle and in a diagnosis of encephalitis. Additional studies are needed to determine the epidemiology and relationships of Sarcocystis spp. that use raptors as intermediate hosts and the importance of Sarcocystis spp. in the overall wellbeing of raptors in their natural environments.

Confirmation of Sarcocystis jamaicensis Sarcocysts in IFN-γ Gene Knockout Mice Orally Inoculated with Sporocysts from a Red-Tailed Hawk ( Buteo jamaicensis)

Here, we report confirmation of sarcocysts of Sarcocystis jamaicensis in an experimental intermediate host, IFN-γ gene knockout (KO) mice orally inoculated sporocysts from its natural definitive host, a red-tailed hawk ( Buteo jamaicensis) (RTH). A RTH submitted to the Carolina Raptor Center, Huntersville, North Carolina, was euthanized because it could not be rehabilitated and released. Fully sporulated sporocysts from intestinal scrapings of the RTH were orally fed to 2 laboratory-reared outbred Swiss Webster mice (SW; Mus musculus) and to 2 KO mice. The sporocysts were infective for KO mice but not to SW mice. Both SW mice remained asymptomatic, and neither schizonts nor sarcocysts were found in their tissues when euthanized on day 54 post-inoculation (PI). The KO mice developed neurological signs and were necropsied 38-54 days PI. Schizonts/merozoites were found in both KO mice euthanized and they were confined to the brain. The predominant lesion was meningoencephalitis. Microscopic sarcocysts were found in muscles of both KO mice. When viewed with light microscopy, the sarcocyst wall appeared thin (<1 μm thick) and smooth. Ultrastructural details of sarcocysts are described.

First molecular characterization and morphological aspects of Sarcocystis fusiformis infecting water buffalo Bubalus bubalis in Egypt

Fresh muscle samples from water buffalo (Bubalus bubalis) aged 2-15, from Giza Province, Egypt; were examined for Sarcocystis infection. Macroscopic ovoid sarcocysts embedded in the muscle tissues of the examined buffaloes were detected; they measured 152-230 (210 ± 7) μm in length and 37-119 (95 ± 3) μm in width. The esophagus was the most infected organ followed by the diaphragm, and tongue, while the heart muscles were the least infected. The cyst cavity was compartmentalized by septa derived from the ground substance located under the primary cyst wall. Using transmission electron microscopy, the primary cyst wall bordered sarcocysts were determined to be 0.08-0.22 μm in thickness, raised from the parasitophorous vacuolar membrane, and surrounded by a secondary cyst wall of host origin. The primary cyst wall had irregular wall folds with numerous cauliflower-like projections of variable sizes and shapes accompanied by knob-like electron-dense elevations. 18S rRNA gene expression studies confirmed that the present parasite isolates belonged to the genus Sarcocystis. The sequence data showed significant identities (>90%) with archived gene sequences from many Eimeriidae organisms, and a dendogram showing the phylogenetic relationship was constructed. The most closely related species was Sarcocystis fusiformis KR186117, with an identity percentage of 98%. The recovered sequences were deposited in the GenBank under the accession number MG572125. The present study, to our knowledge, is the first collective ultrastructural and molecular study that confirmed the taxonomy of sarcocysts isolated from water buffaloes in Egypt as Sarcocystis fusiformis.

Sarcocystosis in South American camelids: The state of play revisited

Members of the genus Sarcocystis (Apicomplexa: Sarcocystidae) are intracellular protozoan parasites that infect a wide range of domestic and wild animals, resulting in economic losses in production animals worldwide. Sarcocystis spp. have indirect life-cycles where canids and felids serve as main definitive hosts while a range of domestic and wild animals serve as intermediate hosts, including South American camelids (SACs) such as alpacas, llamas and guanacos. These animals primarily occur in South American countries on Andean, elevated plains but in recent years, alpacas and llamas have become emerging animal industries in other parts of the world such as Australia, Europe and the USA due to their high-quality fiber, meat and hides. For instance, alpaca meat is becoming popular in many parts of the world due to its lower cholesterol content than other red meat, thereby it has the potential of a valuable product for both local and international markets. However, SAC meat can be degraded and/or even condemned due to the presence of macroscopic sarcocysts in skeletal muscles, leading to significant economic losses to farmers. The infection is generally asymptomatic, though highly pathogenic or even fatal Sarcocystis infections have also been reported in alpacas and llamas. Despite the economic importance of sarcocystosis in SACs, little is known about the life-cycle of parasites involved, disease transmission, epidemiology, pathogenesis, diagnosis, control and public health significance. This review article provides an in-depth analysis of the existing knowledge on the taxonomy, epidemiology, clinicopathology and diagnosis of Sarcocystis in SACs, highlights knowledge gaps and proposes future areas of research that could contribute to our better understanding of sarcocystosis in these animals.

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

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

Small sarcocysts can be a feature of experimental infections with Sarcocystis neurona merozoites

Several reports indicate the presence of small tissue cysts associated with Sarcocystis neurona infections. Several failed attempts to develop tissue cysts in potential intermediate host using in vitro derived parasites originally isolated from horses with equine protozoal myeloencephalitis suggest that the experimental methods to achieve bradyzoites with those isolates was not possible. Those prior studies reported the lack of detectable sarcocysts based on histology and in vivo feeding trials. A recent report of successful production and detection of small sarcocysts triggered us to review archived tissues from earlier experimental infection studies. The retrospective review sought to determine if small sized sarcocysts were not detected due to their relatively smaller size and infrequency as compared to larger sized sarcocysts produced with other isolates in these experimental inoculation trials. Tissues from two prior in vivo inoculation studies, involving in vitro-produced parasites inoculated into laboratory-reared cats and raccoons, were re-examined by immunohistochemistry staining to more easily detect the tissue cysts. In the experimental cat study no small tissue cysts were seen, consistent with the original publication results. However, in the experimental raccoon study, one raccoon inoculated with an EPM-derived isolate, SN-UCD1, had small sarcocysts not reported in the original publication. This retrospective study suggests that much closer scrutiny of tissues, including the use of immunohistochemistry on tissue sections is required to detect the smaller S. neurona sarcocysts associated with the experimental inoculations of the isolates originally derived from horses with EPM.

Sarcocystis neurona and Neospora caninum in Brazilian opossums (Didelphis spp.): Molecular investigation and in vitro isolation of Sarcocystis spp

Sarcocystis neurona and Neospora spp. are protozoan parasites that induce neurological diseases in horses and other animal species. Opossums (Didelphis albiventris and Didelphis virginiana) are definitive hosts of S. neurona, which is the major cause of equine protozoal myeloencephalitis (EPM). Neospora caninum causes abortion in cattle and infects a wide range of animal species, while N. hughesi is known to induce neurologic disease in equids. The aims of this study were to investigate S. neurona and N. caninum in tissues from opossums in the northeastern Brazil, and to isolate Brazilian strains of Sarcocystis spp. from wild opossums for comparison with previously isolated strains. Carcasses of 39 opossums from Bahia state were available for molecular identification of Sarcocystis spp. and N. caninum in their tissues, and for sporocyst detection by intestinal scraping. In addition, Sarcocystis-like sporocysts from nine additional opossums, obtained in São Paulo state, were tested. Sarcocystis DNA was found in 16 (41%) of the 39 opossums' carcasses; N. caninum DNA was detected in tissues from three opossums. The sporocysts from the nine additional opossums from São Paulo state were tested by bioassay and induced infection in nine budgerigars, but in none of the gamma-interferon knockout mice. In vitro isolation was successful using tissues from all nine budgerigars. The isolated strains were maintained in CV-1 and Vero cells. Three of nine isolates presented contamination in cell culture and were discarded. Analysis of six isolates based on five loci showed that these parasites were genetically different from each other and also distinct from S. neurona, S. falcatula, S. lindsayi, and S. speeri. In conclusion, opossums in the studied regions were infected with N. caninum and Sarcocystis spp. and represent a potential source of infection to other animals. This is the first report of N. caninum infection in tissues from black-eared opossum (D. aurita or D. marsupialis) and white-eared opossum (D. albiventris). Brazilian opossums are probably infected by different Sarcocystis spp. distinct from S. neurona and S. falcatula, or present a high level of genetic recombination.

Protozoal-related mortalities in endangered Hawaiian monk seals Neomonachus schauinslandi

Protozoal infections have been widely documented in marine mammals and may cause morbidity and mortality at levels that result in population level effects. The presence and potential impact on the recovery of endangered Hawaiian monk seals Neomonachus schauinslandi by protozoal pathogens was first identified in the carcass of a stranded adult male with disseminated toxoplasmosis and a captive monk seal with hepatitis. We report 7 additional cases and 2 suspect cases of protozoal-related mortality in Hawaiian monk seals between 2001 and 2015, including the first record of vertical transmission in this species. This study establishes case definitions for classification of protozoal infections in Hawaiian monk seals. Histopathology and immunohistochemistry were the primary diagnostic modalities used to define cases, given that these analyses establish a direct link between disease and pathogen presence. Findings were supported by serology and molecular data when available. Toxoplasma gondii was the predominant apicomplexan parasite identified and was associated with 100% of mortalities (n = 8) and 50% of suspect cases (n = 2). Incidental identification of sarcocysts in the skeletal muscle without tissue inflammation occurred in 4 seals, including one co-infected with T. gondii. In 2015, 2 cases of toxoplasmosis were identified ante-mortem and shared similar clinical findings, including hematological abnormalities and histopathology. Protozoal-related mortalities, specifically due to toxoplasmosis, are emerging as a threat to the recovery of this endangered pinniped and other native Hawaiian taxa. By establishing case definitions, this study provides a foundation for measuring the impact of these diseases on Hawaiian monk seals.

Prevalence and first molecular identification of Sarcocystis species in cattle and water buffaloes in India

The importance of Sarcocystis hominis in causing zoonotic infections is well known. Recently, S. hominis like cysts have been reported from water buffalo in China. Previous studies indicate prevalence of Sarcocystis species in bovine populations in India but molecular evidence is required for proper species differentiation. We examined two hundred and ninety six cardiac tissue samples of Indian water buffaloes and cattle from northern and western parts of the country. Tissues were examined for Sarcocystis using intact cyst isolation method, pepsin acid digestion method and Sarcocystis 18S rRNA PCR. The combination of primers was used for 18S rRNA PCR amplification followed by sequencing. Twenty five representative samples were sent for sequencing and 19 readable sequences were obtained for phylogenetic analysis. Overall, the Sarcocystis cysts/zoites were recorded in 44% (95% CI 38-49%), 58% (95% CI 53-64%) and 68% (95% CI 63-73%) from both cattle and buffalo samples using intact cyst isolation, pepsin-HCl digestion method and conventional PCR, respectively. The results indicate that pepsin-HCl digestion method and conventional PCR are more sensitive than intact cyst isolation for detection of Sarcocystis species in tissue samples. The prevalence of Sarcocystis species was high in buffalo as compared to cattle intermediate hosts. Phylogenetic analysis indicated that more than one Sarcocystis species are circulating in cattle and water buffaloes in India. The results further indicate that experimental transmission studies are required to re-confirm the identities and host ranges of the Sarcocystis species in cattle and water buffaloes in India.

Chronic Polymyositis Associated with Disseminated Sarcocystosis in a Captive-born Rhesus Macaque

A 2–year-old, captive-born, clinically healthy male, rhesus macaque, was euthanatized as part of an experimental study. At necropsy, diffuse pale streaking of the trunk, lumbar, and limb muscles were noted macroscopically. On histology, numerous elongated cysts that contained crescent-shaped basophilic spores were found in the fibers of skeletal muscles. Scattered affected myofibers were degenerate and accompanied by eosinophilic-to-granulomatous inflammation. Sarcocysts had prominent villus-like projections with the morphology of a type 11 sarcocyst wall similar to Sarcocystis neurona but possessing many more villus microtubules than is reported for S. neurona. In addition, bradyzoites were very long, up to approximately 12 um in length. The protozoa were consistent with a Sarcocystis sp., based on histology and ultrastructure, however, a definitive identification of the species was not possible. Nonspecific immunohistochemical crossreaction with Sarcocystis cruzi antisera was observed. The 18S ribosomal deoxyribonucleic acid sequence showed 91% similarity to Sarcocystis hominis, 90% similarity to Sarcocystis buffalonis, and 89% similarity to Sarcocystis hirsuta. Interestingly, the ITSI sequence showed very little homology to any sequence in GenBank, suggesting that this is possibly a unique Sarcocystis sp. Sarcocystosis is often considered an incidental finding, particularly in wild-caught animals, with little clinical significance. However, as demonstrated in this report and others, disseminated sarcocystosis can occur in captive-born rhesus macaques with or without clinical signs. In some cases interference with research results can occur; including death in fulminant cases.

Effects of Blood Contamination of Cerebrospinal Fluid on Results of Indirect Fluorescent Antibody Tests for Detection of Antibodies against Sarcocystis Neurona and Neospora Hughesi

The purpose of this study was to determine the effect of blood contamination of cerebrospinal fluid (CSF) on the results of indirect fluorescent antibody tests (IFATs) for Sarcocystis neurona and Neospora hughesi. The in vitro study used antibody-negative CSF collected from non-neurologic horses immediately after euthanasia and blood samples from 40 healthy horses that had a range of IFAT antibody titers against S. neurona and N. hughesi. Serial dilutions of whole blood were made in seronegative CSF to generate blood-contaminated CSF with red blood cell (RBC) concentrations ranging from 10 to 100,000 RBCs/μl. The blood-contaminated CSF samples were then tested for antibodies against both pathogens using IFAT. Blood contamination of CSF had no detectable effect on IFAT results for S. neurona or N. hughesi at any serologic titer when the RBC concentration in CSF was <10,000 RBCs/μl. At concentrations of 10,000-100,000 RBCs/μl of CSF, positive CSF results (IFAT titer ≥5) for S. neurona and N. hughesi were detected only when the corresponding serum titers were ≥160 and ≥80, respectively. The IFAT performed on CSF is reliable for testing horses for equine protozoal myeloencephalitis caused by S. neurona or N. hughesi, even when blood contamination causes the RBC concentration in CSF to be up to 10,000 RBCs/μl.

Accipiter hawks (Accipitridae) confirmed as definitive hosts of Sarcocystis turdusi, Sarcocystis cornixi and Sarcocystis sp. ex Phalacrocorax carbo

Sarcocystis is a large genus of protozoan parasites with complex heteroxenous life cycles. For many species, either the intermediate or the definitive host is still unknown. In this study, 116 Accipiter hawks (Eurasian sparrowhawks and northern goshawks) were investigated for the presence of Sarcocystis spp. in their intestinal tract or their faeces. To gain a wide distribution, samples were collected throughout Germany within 2 years. It was possible to detect Sarcocystis-like oocysts in 65 samples. Sequencing of the ITS region or species-specific PCR identified 33 samples as Sarcocystis turdusi/Sarcocystis sp. ex A. nisus (18), Sarcocystis calchasi (6), Sarcocystis columbae (3), Sarcocystis cornixi (3) and Sarcocystis sp. ex Phalacrocorax carbo (3). Besides the known infestation with S. columbae, S. sp. ex A. nisus and S. calchasi the Accipiter hawks were thereby confirmed as definitive host of S. turdusi, S. cornixi and S. sp. ex Phalacrocorax carbo for the first time.

Morphologic and molecular characteristics of Sarcocystis atraii n. sp. (Apicomplexa: Sarcocystidae) infecting the common coot (Fulica atra) from Egypt

A single morphologic type of Sarcocystis cysts found in two out of 43 examined common coots, Fulica atra, is considered to represent a new species for which the name Sarcocystis atraii n. sp. is proposed and its description is provided. Coots were hunted from the vicinity of Brolos Lake located at KafrElsheikh province, Egypt. The structural morphology of the revealed sarcocysts was described using light and transmission electron microscopy. Sarcocysts were found in the leg and thigh muscles. The cysts were microscopic and measured 165-850 μm in length × 50-85 μm in width. Histologically; the sarcocyst wall was wavy and had minute undulations. Ultrastructurally, it measured 1-3 μm in thickness and possessed many mushroom-like villar protrusions sometimes originating from other mushroom-like villar protrusions that measured approximately 0.5-2 μm in length and up to 2 μm in width, with the presence of electron dense ground substance of 300 nm to 1 μm thick. The bradyzoites were elongated, banana-shaped and measured 7.5-14 × 1.5-2.5 μm, with centrally or terminally located nuclei. The ultrastructural features of the cyst wall belonged to type 24. On the basis of sequencing and phylogenic analyses for 18S rRNA , 28S rRNA genes and ITS-1 region; S. atraii n. sp. is considered a genetically distinct species, being most closely related to avian Sarcocystis spp. whose definitive hosts are predatory mammals.

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.

Light microscopy and molecular identification of Sarcocystis spp. in meat producing animals in Selangor, Malaysia

One thousand and forty-five tissue samples of skeletal muscles, tongue, heart, diaphragm and esophagus were collected from 209 animals (43 sheep, 89 goats and 77 cattle) from an abattoir in Selangor between February and October, 2013. Each sample was divided into three pieces with each piece measuring 2-3 mm3. Each piece was then squeezed between two glass slides and examined microscopically at x 10 magnification for the presence of sarcocystosis. Three positive samples from each animal species were then fixed in 10% formalin for histological processing. Seven positive samples collected from each animal species were preserved at -80°C or 90% ethanol for gene expression studies. Microsarcocysts were detected in 114 (54.5%) animals by light microscopy (LM). The infection rates in sheep, goat and cattle were 86, 61.8 and 28.6% respectively. The highest rate of infection was in the skeletal muscles of sheep (64.9%) and goats (63.6%) and in the heart of cattle (63.6%). The cysts were spindle to oval in shape and two stages were recognized, the peripheral metrocytes and centrally located banana-shaped bradyzoites. 18S rRNA gene expression studies confirmed the isolates from the sheep as S. ovicanis, goats as S. capracanis and cattle as S. bovicanis. This, to the best of our knowledge, is the first molecular identification of an isolate of S. ovicanis and S. capracanis in Malaysia. Further studies with electron microscopy (EM) are required in the future to compare the features of different types of Sarcocysts spp.

Molecular evidence of Sarcocystis species in captive snakes in Japan

Sarcocystis nesbitti, using snakes as the definitive host, is a causative agent of acute human muscular sarcocystosis in Malaysia. Therefore, it is important to explore the distribution and prevalence of S. nesbitti in snakes. Nevertheless, epizootiological information of S. nesbitti in snakes remains insufficient because few surveys have assessed Sarcocystis infection in snakes in endemic countries. In Japan, snakes are popular exotic pet animals that are imported from overseas, but the degree of Sarcocystis infection in them remains unclear. The possibility exists that muscular sarcocystosis by S. nesbitti occurs in contact with captive snakes in non-endemic countries. For a total of 125 snake faecal samples from 67 snake species collected at animal hospitals, pet shops and a zoo, this study investigated the presence of Sarcocystis using polymerase chain reaction (PCR) for the 18S ribosomal RNA gene (18S rDNA). Four (3.2%) faecal samples were positive by PCR. Phylogenetic analysis of the 18S rDNA sequences obtained from four amplification products revealed one isolate from a beauty snake (Elaphe taeniura), Sarcocystis zuoi, which uses rat snakes as the definitive host. The isolate from a Macklot's python (Liasis mackloti) was closely related with unidentified Sarcocystis sp. from reticulated pythons in Malaysia. The remaining two isolates from tree boas (Corallus spp.) were closely related with Sarcocystis lacertae, Sarcocystis gallotiae and unidentified Sarcocystis sp. from smooth snakes, Tenerife lizards and European shrews, respectively. This report is the first of a study examining the distribution of Sarcocystis species in captive snakes in Japan.

Molecular identification of Sarcocystis rileyi sporocysts in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in Lithuania

Despite the fact that Sarcocystis rileyi is one of the earliest described species of the genus Sarcocystis forming macrocysts in ducks, the life cycle of this species is still unknown in Europe. Sarcocystis spp. oocysts/sporocysts were observed in faeces of four of 23 (17.4 %) and in small intestine mucosal scrapings of four of 20 (20.0 %) red foxes (Vulpes vulpes) and in small intestine mucosal scrapings of seven of 13 (53.8 %) raccoon dogs (Nyctereutes procyonoides) hunted in Lithuania. A very small number of Sarcocystis sporocysts measuring 11.9 × 8.3 μm (n = 5) was found in faecal samples, whereas considerably more sporulated Sarcocystis oocysts and free sporocysts were detected in the small intestines of red foxes and raccoon dogs. These sporocysts measured 12.9 × 8.1 μm (n = 16) and 12.1 × 8.1 μm (n = 54) in red foxes and raccoon dogs, respectively. Using species-specific PCR and subsequent sequencing, internal transcribed spacer 1 (ITS-1) region partial sequences of oocysts/sporocysts from small intestine mucosal scrapings of six raccoon dogs and three red foxes were identified as belonging to S. rileyi. The present study provides strong evidence showing that the red fox and the raccoon dog can serve as final hosts of S. rileyi in Europe; however, transmission experiments are needed for the ultimate approval.

Neglected tropical diseases among two indigenous subtribes in peninsular Malaysia: highlighting differences and co-infection of helminthiasis and sarcocystosis

Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0-33.0), followed by Giardia spp. (n = 3; 3.1%, -0.3-6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0-13.8), Cryptosporidium spp. (n = 3, 1.8%, -0.2-3.8) and Giardia spp. (n = 2, 1.2%, -0.4-2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.

Microscopic and molecular characterization of Hepatozoon domerguei (Apicomplexa) and Foleyella furcata (Nematoda) in wild endemic reptiles from Madagascar

Madagascar is one of the world's top twelve "megadiversity" hot spots hosting unique and threatened flora and fauna. Parasites are a major component of biodiversity but remain largely uncharacterized in wildlife. In this study we combine microscopic and molecular assessment of hemoparasites in endemic reptile species from Madagascar. We detected three distinct parasites: the apicomplexans Hepatozoon and Sarcocystis, and filarial nematodes. The prevalence and intensity of these apicomplexans were low overall, while microfilarial infections in chameleons were relatively high. We detected mixed infections of two Hepatozoon haplotypes in Madagascarophis colubrinus, and of Hepatozoon and microfilariae in a Furcifer sp. Phylogenetic analyses of Hepatozoon showed evidence of prey-predator transmission, with identical sequences found in the snakes M. colubrinus and Ithycyphus oursi, and their prey Furcifer sp. Based on previous studies regarding the life cycle of Hepatozoon domerguei Landau, Chabaud, Michel, and Brygoo, 1970 in these hosts and due to their morphological similarity, we propose that this Hepatozoon haplotype is Hepatozoon domerguei. Future studies, including the examination of invertebrate hosts, are needed to verify this preliminary taxonomic identification. A distinct hemogregarine haplotype was found in Oplurus sp., which displayed morphologically different gametocytes, some of which were apparently inside leukocytes. The Sarcocystis identified from Tracheloptychus petersi was identical to that reported in a North African snake, indicating that the same lineage is found in geographically distinct regions. By combining morphological and genetic information, Foleyella furcata (Linstow, 1899) filarial nematodes were identified in several Furcifer chameleons. This study provides insights into the distribution, diversity and host-parasite interactions of hemoparasites in wild reptile populations from Madagascar.

Outbreak of human infection with Sarcocystis nesbitti, Malaysia, 2012

An outbreak of fever associated with myalgia and myositis occurred in 2012 among 89 of 92 college students and teachers who visited Pangkor Island, Malaysia. The Sarcocystis nesbitti 18S rRNA gene and sarcocysts were obtained from muscle tissues of 2 students. Our findings indicate emergence of S. nesbitti infections in humans in Malaysia.

Prevalence of Sarcocystis spp. and Hammondia spp. microcysts in esophagus tissue of sheep and cattle, emphasized on their morphological differences

Sarcocystis and Hammondia are two obligatory protozoan parasites. These genera belong to cyst-forming coccidia group of the phylum Apicomplexa. They both need two different hosts to complete their life cycles. Felids and canids can act as definitive hosts, while herbivores, such as sheep and cattle, are the most important intermediate hosts. Reports verify that no important disease has been caused by Hammondia spp.; on the other hand, Sarcocystis spp. can cause some severe infectious disease in livestock industry such as abortion. Economic losses are another concern due to carcass condemnation during meat inspection in abattoirs and decrease in the quality and quantity of milk and wool production. Due to the Sarcocystis and Hammondia tissue cysts being similar, the distinction between these different genera is so important. In this study, the prevalence of Sarcocystis and Hammondia in the esophagus tissue of sheep and cattle slaughtered in one of the industrial abattoir in Iran was reported and an easy and rapid method for accurate diagnosing of Sarcocystis and Hammondia bradyzoites was explained.

Sarcocystis nesbitti causes acute, relapsing febrile myositis with a high attack rate: description of a large outbreak of muscular sarcocystosis in Pangkor Island, Malaysia, 2012

Background

From the 17^th to 19^th January 2012, a group of 92 college students and teachers attended a retreat in a hotel located on Pangkor Island, off the west coast of Peninsular Malaysia. Following the onset of symptoms in many participants who presented to our institute, an investigation was undertaken which ultimately identified Sarcocystis nesbitti as the cause of this outbreak.

Methodology/Principal Findings

All retreat participants were identified, and clinical and epidemiological information was obtained via clinical review and self-reported answers to a structured questionnaire. Laboratory, imaging and muscle biopsy results were evaluated and possible sources of exposure, in particular water supply, were investigated. At an average of 9–11 days upon return from the retreat, 89 (97%) of the participants became ill. A vast majority of 94% had fever with 57% of these persons experiencing relapsing fever. Myalgia was present in 91% of patients. Facial swelling from myositis of jaw muscles occurred in 9 (10%) patients. The median duration of symptoms was 17 days (IQR 7 to 30 days; range 3 to 112). Out of 4 muscle biopsies, sarcocysts were identified in 3. S. nesbitti was identified by PCR in 3 of the 4 biopsies including one biopsy without observed sarcocyst. Non-Malaysians had a median duration of symptoms longer than that of Malaysians (27.5 days vs. 14 days, p = 0.001) and were more likely to experience moderate or severe myalgia compared to mild myalgia (83.3% vs. 40.0%, p = 0.002).

Conclusions/Significance

The similarity of the symptoms and clustered time of onset suggests that all affected persons had muscular sarcocystosis. This is the largest human outbreak of sarcocystosis ever reported, with the specific Sarcocystis species identified. The largely non-specific clinical features of this illness suggest that S. nesbitti may be an under diagnosed infection in the tropics.

Sarcocystis species are protozoan organisms that have been associated with disease in animals but less frequently so in humans. Following a retreat on Pangkor Island off Peninsular Malaysia, a number of persons presented to our hospital with prolonged fever and muscle pain that was initially difficult to attribute to a known infectious cause. Investigations, including muscle biopsies and PCR, showed that this outbreak was most likely due to Sarcocystis nesbitti infection. The most common clinical features were fever and myalgia that was relapsing-remitting in more than half the patients. Some patients had visible swelling of muscle groups, including of the face, with magnetic resonance imaging also demonstrating inflammation in these muscles. Herein, we present the clinical and investigation findings in 89 symptomatic persons in the largest reported outbreak of human muscular sarcocystosis to date. Our findings provide insights and suggestions for the most appropriate forms of investigation, treatment and possible source of infection.

[Emerging parasitic diseases]

Travels, migration and circulation of goods facilitate the emergence of new infectious diseases often unrecognized outside endemic areas. Most of emerging infections are of viral origin. Muscular Sarcocystis infection, an acute illness acquired during short trips to Malaysia, and Chagas disease, a chronic illness with long incubation period found among Latin American migrants, are two very different examples of emerging parasitic diseases. The former requires a preventive approach for travelers going to Malaysia and must be brought forth when they return with fever, myalgia and eosinophilia, while the latter requires a proactive attitude to screen Latin American migrant populations that may face difficulties in accessing care.

Molecular identification of Sarcocystis hominis in native cattle of central Iran: a case report

Sarcocystis spp. are two-host protozoan parasites belonging to the phylum Apicomplexa. Among different known species of Sarcocystis in cattle, only Sarcocystis hominis is important from the public health viewpoint, because of its zoonotic characteristics. This study presents the first molecular identification of S. hominis in native cattle in central Iran. A sample of diaphragm muscle from a 6-year-old native cow slaughtered at Yazd Slaughterhouse, Yazd, central Iran, was collected in May 2013. DNA extraction was performed, using the salting-out method. DNA purification and precipitation were performed consecutively. The amplicon and digestion results were analyzed using agarose gel electrophoresis. A PCR product with 926 bp in length was obtained after amplification, and 376 bp and 550 bp in length after digestion that identified S. hominis. To the best of our knowledge, this study is the first of its kind to be reported from Iran.

Description of Sarcocystis lari sp. n. (Apicomplexa: Sarcocystidae) from the great black-backed gull, Larus marinus (Charadriiformes: Laridae), on the basis of cyst morphology and molecular data

A morphological type of Sarcocystis cysts found in one of two examined great black-backed gull, Larus marinus (Linnaeus) (Laridae), is considered to represent a new species for which the name Sarcocystis lari sp. n. is proposed and its description is provided. The cysts are ribbon-shaped, very long (the largest fragment found was 6 mm long) and relatively narrow (up to 75 microm). Under a light microscope the cyst wall reaches up to 1 microm and seems to be smooth. Using a computerized image analysis system, knolls, which resemble protrusions on the wall surface, are visible. Lancet-shaped cystozoites measure in average 6.9 x 1.4 microm (range 6.3-7.9 microm x 1.2-1.5 microm) in length. Observed using Transmission electron microscopy (TEM), the cyst wall is wavy and measures up to 1.2 microm in thickness. The parasitophorous vacuolar membrane has regularly arranged small invaginations. Cyst content is divided into large chambers by septa. Sarcocystis lari sp. n. has type-1 tissue cyst wall and is morphologically indistinguishable from other bird Sarcocystis species characterized by the same type of the wall. On the basis of 18S rRNA gene, 28S rRNA gene and ITS-1 region sequences, S. lari is a genetically distinct species, being most closely related to avian Sarcocystis species whose definitive hosts are predatory birds.

High prevalence of muscular sarcocystosis in cattle and water buffaloes from Selangor, Malaysia

The prevalence of sarcocystosis in cattle and water buffaloes from peninsular Malaysia was investigated in abattoirs in Selangor state, February, 2011, to March, 2012. Fresh muscle samples were collected from the tongue, heart, oesophagus, diaphragm and skeletal muscles of 102 cattle and 18 water buffaloes. Each sample was initially screened by light microscopy and then fixed for further histopathological analysis. Out of 120 animals examined, 49 (40.8%) harboured the microscopic type of Sarcocystis spp. The positivity rate for cattle was 36.2% and for water buffaloes 66.7%. In cattle, the organs highly infected were the skeletal muscles and diaphragm (27% each), followed by tongue and esophagus (24.3% each), and the heart (8%). In water buffaloes, the heart was most often infected (66.7%), followed by the oesophagus (50%) and skeletal muscle (33.3%); no sarcocysts were detected in the tongue and diaphragm. The shape of the sarcocyst was fusiform to oval with a mean cyst size of 151.66 x 75.83 μm and wall thickness of 2.47 μm in cattle, and 114 x 50.81 μm cyst size and the wall thickness of 1.11 μm in water buffaloes, consistent with Sarcocystis cruzi and Sarcocystis levinei, respectively. Remaining tissue from cattle was subjected to parasite specific 18S rRNA gene PCR and Sarcocystis cruzi was confirmed, at least exemplarily. The peripheral metrocytes and the banana-shaped bradyzoites (15.23 x 2.2 μm in cattle and 11.49 x 2.45 μm in water buffalo hosts) were easily recognized. In conclusion, a high positivity rate was found in Malaysian meat-producing animals with possible implications for meat consumption and human health.