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

Detection of Sarcocystis hominis, Sarcocystis bovifelis, Sarcocystis cruzi, Sarcocystis hirsuta and Sarcocystis sigmoideus sp. nov. in carcasses affected by bovine eosinophilic myositis

Bovine eosinophilic myositis is an inflammatory myopathy characterized by multiple focal or diffuse grey to green patches leading to condemnation of affected carcasses. Although its etiology is still uncertain, there is evidence that Sarcocystis species may play a role in the development of eosinophilic myositis. The goal of the present study was to identify Sarcocystis spp. in intralesional and extralesional tissues of condemned cattle carcasses, in order to evaluate the possible role of different bovine Sarcocystis spp. in the etiology of bovine eosinophilic myositis. Muscle samples (n = 100) of 26 affected carcasses were collected in Northern Italy. One to five samples with lesions and two aliquots of tissue without lesions were collected from each carcass; lesions were grossly categorized in green focal lesions and green diffuse patches. Genomic DNA was extracted and analyzed by multiplex-PCR targeting different Sarcocystis spp. Unidentified species were characterized morphologically (light microscopy, histology), ultrastructurally (scanning and transmission electron microscopy) and on the molecular level (complete 18S rRNA gene and partial cox1 gene sequencing). A bovine eosinophilic myositis prevalence of 0.017% was visually assessed by routine carcass inspection between 2014 and 2019 in Italy (184/1,108,150 slaughtered cattle). Out of 26 carcasses, 25 revealed the presence of at least one Sarcocystis species (96.2%). The presence of Sarcocystis spp. DNA was significantly more frequent in intralesional than in extralesional samples. Considering the different species, Sarcocystis bovifelis and Sarcocystis hominis were significantly more frequent in intralesional (41.7% and 50%, respectively) than in extralesional samples (1.9% and 15.4%, respectively), while there was no significant difference between the presence of Sarcocystis cruzi and Sarcocystis hirsuta in intralesional (27.1% and 2.1%, respectively) and extralesional (30.8% and 1.9%, respectively) samples. The presence of an unnamed Sarcocystis sp. showing thick-walled (3.7-5.4 μm) cysts with densely packed, flattened, undulating and narrow protrusions, which showed an S-shape in side view, was recorded in the diaphragm of two carcasses. Genomic DNA from individual sarcocysts isolated from the diaphragm was successfully amplified and further sequenced. Sequence comparison revealed <94.6% and 83.4% identity at 18S rRNA and cox1 genes, respectively, with other named Sarcocystis spp., while the phylogenetic analysis clearly separated the unnamed Sarcocystis sp. from the other Sarcocystis spp. using cattle as intermediate hosts. The present study contributes to the understanding of the importance of different Sarcocystis spp. in the pathogenesis of bovine eosinophilic myositis. The results emphasize the association of Sarcocystis hominis and Sarcocystis bovifelis with bovine eosinophilic myositis and highlight the presence of a new Sarcocystis sp. using cattle as intermediate hosts. The name Sarcocystis sigmoideus sp. nov. is proposed for the newly described Sarcocystis species.

A Case of Bovine Eosinophilic Myositis (BEM) Associated with Co-Infection by Sarcocystis hominis and Toxoplasma gondii

Bovine eosinophilic myositis (BEM) is a specific inflammatory myopathy, often associated with Sarcocystis spp., with multifocal gray-green lesions leading to carcass condemnation with considerable economic losses. Here is described a peculiar case of BEM that occurred in an adult (16 month) cattle, born in France, bred, and slaughtered in Italy at the end of 2021. On inspection, muscles showed the typical multifocal gray-green lesions that were sampled for, cytological, histological, and molecular investigations, while meat juice was subjected to IFAT for Toxoplasma IgG. Genomic DNA was extracted from lesions, portions of healthy muscle and from meat juice pellet and analyzed by PCR targeting 18S rDNA, COI mtDNA and B1 genes, and sequenced. The cytology showed inflammatory cells mostly referable to eosinophils; at histology, protozoan cysts and severe granulomatous myositis were observed. A BEM lesion and meat juice pellet subjected to PCR showed, concurrently, sequences referable both to S. hominis and T. gondii. Meat juice IFAT resulted negative for T. gondii IgG. Our findings highlight the first detection of T. gondii DNA in association with S. hominis in a BEM case, suggesting a multiple parasite infection associated with this pathology, although the actual role of T. gondii infection in the pathophysiology of the diseases should be clarified.

Bovine sarcocystosis: Sarcocystis species, diagnosis, prevalence, economic and public health considerations, and association of Sarcocystis species with eosinophilic myositis in cattle

Infections by Sarcocystis in cattle are ubiquitous worldwide. There is considerable debate concerning the identity of Sarcocystis spp. in cattle. Proper diagnosis of Sarcocystis spp. is important to assess their economic and public health importance. Currently there are seven named species: Sarcocystis hirsuta, Sarcocystis cruzi, Sarcocystis hominis, Sarcocystis bovifelis, arcocystis heydorni, Sarcocystis bovini and Sarcocystis rommeli. Additionally, there are unnamed Sarcocystis spp. Two species, S. hominis and S. heydorni, are zoonotic. One out of seven species (S. hirsuta, contracted from cats) forms macroscopic cysts which can be visible during carcass inspection. Current molecular characterization is based on DNA extracted from sarcocysts from naturally infected cattle because DNA was not characterized from tissues of experimentally infected cattle or feces of experimentally infected definitive hosts. Sarcocystis cruzi (transmitted via canids) is recognized as the most pathogenic species and it causes abortion, low milk yield, poor body growth, and outbreaks of clinical sarcocystosis and death. Additionally, Sarcocystis infections have been linked to an inflammatory condition of striated muscles termed bovine eosinophilic myositis (BEM). Cattle affected by BEM appear clinically normal. Diagnosis of BEM at slaughter occurs when inspecting the carcass surface, or once the carcass has been divided into prime cuts or quarters. Sex and breed have no apparent influence on prevalence of BEM. The condition evidently occurs with equal frequency in steers, cows, and heifers. Virtually all striated muscles can be affected including skeletal muscles, the muscles of the eye, larynx, and the heart. In the USA, regulations require condemnation of BEM-affected parts, or (in severe cases) the entire carcass. These aesthetic considerations result in economic losses. Cattle experimentally infected with Sarcocystis did not have BEM at slaughter. Here, we review the status of Sarcocystis spp. and BEM in cattle including prevalence, lesions, epidemiology, and association of BEM with different species of Sarcocystis.

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 detection of cattle Sarcocystis spp. in North-West Italy highlights their association with bovine eosinophilic myositis

Background

Cattle are intermediate hosts of six Sarcocystis species, among which Sarcocystis hominis and Sarcocystis heydorni can infect humans through the consumption of raw or undercooked meat. In addition to the zoonotic potential, there is increasing interest in these protozoa because of the evidence supporting the role of Sarcocystis spp. in the occurrence of bovine eosinophilic myositis (BEM), a specific inflammatory myopathy which leads to carcass condemnation and considerable economic losses. Actually, all the prevalence studies carried out on cattle in Italy have been based on either morphological or 18S rDNA-based molecular techniques, most likely leading to misidentification of closely related species. Therefore, there is a strong need for new data on the prevalence of the different Sarcocystis spp. in cattle in Italy and their association with bovine eosinophilic myositis.

Methods

To reach our aim, individual striated muscle samples from BEM condemned carcasses (N = 54) and diaphragm muscle samples from randomly sampled carcasses (N = 59) were obtained from Northwest Italy slaughterhouses. Genomic DNA was extracted and analyzed by multiplex-PCR targeting 18S rDNA and cox1 genes. PCR products amplified using the genus-specific primer set in absence of the specific fragment for S. hirsuta, S. cruzi, S. hominis or S. bovifelis were sequenced to achieve species identification.

Results

Sarcocystis DNA was detected in 67.8% of the samples from slaughter cattle and in 90.7% of the samples from BEM condemned carcasses. S. cruzi was identified as the most prevalent species in slaughter cattle (61%), followed by S. bovifelis (10.2%), S. hominis (8.5%) and S. hirsuta (1.7%). Notably, among the different Sarcocystis spp. detected, the presence of S. bovifelis and S. hominis was significantly higher in samples isolated from BEM condemned carcasses (46.3% and 40.7% respectively), while there was no statistically significant difference between the presence of S. cruzi or S. hirsuta in BEM condemned carcasses (42.6% and 1.8%, respectively) and randomly sampled carcasses. Furthermore, DNA sequence analysis revealed the presence of a putative new species in two carcasses.

Conclusions

Our study contributes to updating the data on the prevalence of the different Sarcocystis spp. in cattle in Italy, highlighting the presence of three Sarcocystis spp., S. cruzi, S. hominis and S. bovifelis, in BEM lesions and allowing us to speculate on the possible role of S. hominis and S. bovifelis as the major sarcosporidian species involved in bovine eosinophilic myositis.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04722-5.

Zoonotic Sarcocystis

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

Molecular identification of four Sarcocystis species in cattle from Lithuania, including S. hominis, and development of a rapid molecular detection method

Background

Six Sarcocystis species are known to use cattle (Bos taurus) as the intermediate host, two of which, S. hominis and S. heydorni, are zoonotic. There is a need for a method that will enable rapid identification of the Sarcocystis species in cattle.

Methods

The diaphragm muscles of 102 cattle from Lithuania were examined for the presence of Sarcocystis spp., using two different methods for species identification. Individual sarcocysts were isolated from squash preparations of the diaphragm muscle under the light microscope, followed by genetic characterisation of excised cysts using sequence analysis of the 18S rRNA (18S rRNA) and cytochrome c oxidase subunit I (cox1) genes. The same cattle muscle samples were digested and species-specific PCR analyses targeting cox1 were developed to identify the Sarcocystis isolates to the species level.

Results

Under the light microscope, sarcocysts were detected in 87.3% of animals, and Sarcocystis infection was verified in all digested samples. Three species, namely S. cruzi (n = 20), S. bovifelis (n = 23) and S. hirsuta (n = 6), were identified by DNA sequence analysis of isolated sarcocysts. Based on sequence analysis of cox1, the level of genetic variability depended on Sarcocystis species and geographical location. Four Sarcocystis species, S. cruzi (96.1%), S. bovifelis (71.6%), S. hirsuta (30.4%) and S. hominis (13.7%), were confirmed in the digested samples. In individual samples, the most common finding was two species of Sarcocystis (44.1%), followed by three species (26.5%), a single species (24.5%) and four species (4.9%).

Conclusions

Although examination of tissue preparations under the light microscrope did not detect any sarcocysts belonging to S. hominis, this species was identified in the digested samples subjected to a cox1-specific PCR analysis. These results demonstrate the need for effective molecular diagnosis techniques to detect Sarcocystis spp., which may be present at a lower prevalence and not detectable among the limited number of sarcocysts identified individually under the light microscope.

Prevalence and molecular analysis of Sarcocystis infections in cattle in Northwest Iran and the first global report of S. gigantea in cattle

Cattle are intermediate host for several species of Sarcocystis, including S. cruzi, S. hirsuta, and S. hominis with high prevalence worldwide. The present study aimed to determine the prevalence of Sarcocystis infection, species identification, and phylogenetic analysis of the parasite in cattle in Northwest Iran. The samples of diaphragm and esophagus from 290 cattle were collected from slaughterhouses in Northwest Iran and subjected to macroscopic, microscopic, and histopathology examinations, PCR-RFLP, sequencing and phylogenetic analyses. Tissue cysts of Sarcocystis spp. were detected in 92% of cattle by digestion and microscopic tests. Based on the PCR-RFLP and specific PCR, 87.9% and 1.03% of isolates were identified as S. cruzi, and S. hominis, respectively. Macrocyst was seen in a single sample that was identified as S. gigantea. The haplotype network exhibited the extension of the various haplotypes of S. cruzi between neighboring provinces in Northwest Iran. Heterogeneity analysis of S. cruzi 18S-rRNA sequences indicated genetic diversity among S. cruzi isolates (Haplotype diversity: 0.733-0.854) consisting 16 haplotypes; however, the nucleotide differences showed low diversity (0.01481 to 0.03351). Pair wise sequence distance matrix amongst S. cruzi sequences indicated an intra-species divergence of 0%-7.8% and identity of 92.6%-100%. Sarcocystis infection is highly prevalent in cattle in Northwest Iran, with the predominance of S. cruzi, and genetic variants of this species are unequivocally distributing in Northwest provinces. First global detection of S. gigantea in cattle reflects new insights of transmission dynamic and biology of this parasite in Iran.

Molecular differentiation of cattle Sarcocystis spp. by multiplex PCR targeting 18S and COI genes following identification of Sarcocystis hominis in human stool samples

Sarcocystis spp. are protozoan parasites which can infect a wide range of vertebrates, including humans; the latter can act as definitive hosts for two cattle Sarcocystis spp.: Sarcocystis hominis and Sarcocystis heydorni. Reports of intestinal sarcocystosis are well documented in the literature, but PCR-based methods have been scarcely used to identify Sarcocystis species in human stools, and have been limited to the molecular analysis of 18S ribosomal RNA (18S rRNA) gene sequences. Since the mitochondrial cytochrome c oxidase subunit I (COI) gene is one of the most promising tools for distinguishing between closely related Sarcocystis spp., and taking into account the lack of publicly available S. hominis COI sequences, in the present study we obtained the first partial COI sequence of S. hominis from human stool samples of patient with gastrointestinal symptoms. We designed specific COI primers to develop a multiplex PCR method for the identification of Sarcocystis spp. in cattle. The submission of the COI sequence described herein and the unambiguous identification of S. hominis through the application of the new multiplex PCR is important for determining the prevalence of this zoonotic Sarcocystis spp. in meat and the risk for consumers.

Sarcocystis spp. in Romanian Slaughtered Cattle: Molecular Characterization and Epidemiological Significance of the Findings

Species of the genus Sarcocystis are recognized as protozoan parasites infecting a wide range of animals, including humans. This study aimed to provide data on the occurrence, genetic characterization, and epidemiological significance of Sarcocystis spp. in cattle destined for human consumption in Romania. A total of 117 heart samples from slaughtered cattle in three southwestern Romanian counties (Dolj, Timiș, and Gorj) were analyzed in order to detect sarcocysts, using fresh examination microscopic techniques. Subsequently, the isolated sarcocysts and/or cyst fragments (5-15 per sample) from each infected animal were molecularly characterized. Overall, 17.9% (21/117) of the tested animals were found to be Sarcocystis spp. positive by microscopy. Genetic characterization of Sarcocystis spp. isolates, based on sequence analysis of the 18S rRNA gene, showed the presence of a single species, namely S. cruzi. No correlation was found (p > 0.05) between S. cruzi infection and the origin, age, breed, and gender of cattle, but the grazing farming system was positively associated (p=0.031) with the pathogen prevalence and can be considered a risk factor (OR = 3.6) in acquiring infection. To evaluate the possible public health risk, further investigation focused on the processing of other Sarcocystis-specific tissue matrices and evidence of human infections is recommended. This is the first study of bovine Sarcocystis infection in Romania.

Sarcosporidiosis: An Emerging Disease in Yaks (Bos grunniens) on the Qinghai Tibetan Plateau (QTP), China

BACKGROUND

Sarcocystosis is a worldwide distributed parasitic zoonosis. However, scarce knowledge is available about the infection of sarcocystosis in yaks.

RESULTS

Herein, we conducted this study to survey the seroprevalence of sarcocystosis in yaks on the Qinghai Tibetan plateau. A total of 2549 serum samples were obtained during 2011-2017, which were assayed using commercial ELISA kits. The results revealed that the overall seroprevalence of sarcosporidiosis in QTP yaks was 0.90% (95 CI 0.6-1.4). The seroprevalence ranged from 0.20% (95 CI 0-1.1) to 1.67% (95 CI 0.8-3.0) in yaks in different areas. The seroprevalence was 0.73% (95 CI 0.3-1.4) in male yaks and 0.06% (95 CI 0.6-1.8) in female yaks. In different ages, the seroprevalence ranged from 0 (95 CI 0-1.4) to 1.47% (95 CI 0.6-3.0). In different years, the seroprevalence ranged from 0 (95 CI 0-1.4) to 1.86% (95 CI 0.7-4.0). In the current study herein, region and age were revealed to be the obvious influencing risk factors by conditional stepwise logistic regression.

DISCUSSION

The current study herein first found the emerging infection of sarcosporidiosis in yaks from high plateaus, which contributes to outline the epidemiological scenario of sarcosporidiosis in yaks in China. Moreover, our findings highlight the urgent need of studies in yaks on the QTP at further and more comprehensive level.

PCR-RFLP at 18S rRNA gene for identification of Sarcocystis species and their prevalence in cattle of Andhra Pradesh

In the present study, the species specific determination of Sarcocystis cysts isolated from 137 naturally infected and slaughtered cattle from different regions of Chittoor district, Andhra Pradesh, India was achieved by PCR-RFLP. Diagnosis of sarcocysts in cattle was based on macroscopic examination and pepsin digestion method. Genomic DNA was extracted individually from bradyzoites of all 137 sarcocystosis positive cattle and all the isolates were characterized at 18S rRNA. Digestion of PCR amplicons (900 bp) with restriction endonuclease revealed 3 different electromorphs which were referred to Sarcocystis cruzi (513 and 343 bp), S. hirsuta (525, 241 and 141 bp) and S. fusiformis (532 and 335 bp). Sarcocystis cruzi (93.43%) was significantly more prevalent in comparison with the S. hirsuta (4.38%) and S. fusiformis (2.19%). Infection of cattle with S. hominis was not observed in the study area. Occurrence of S. fusiformis in cattle supports that Sarcocystis species of buffaloes are not strictly intermediate host specific however can infect cattle.

Biochemical profile of blood in naturally occurring Sarcocystis infection in cattle

The aim of this study was to determine the biochemical blood indicators in Lithuanian Black-and-White cattle with regard to the intensity of their infection with Sarcocystis spp. In total 945 bull muscle samples and 120 blood samples were used for the analysis. Aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) were increased in infected animals relative to uninfected animals. The AST levels differed significantly between the no infection, low, and moderate infection groups (P < 0.05); ALP differed between the no infection and moderate infection groups (P < 0.05); and ALT differed between the no infection, low infection and intense infection groups (P < 0.05). Total protein levels were higher than physiological limits and differed significantly between the no infection, low infection and intense infection groups (P < 0.05). Iron levels were at the lowest physiological limits and differed significantly between the no infection and low infection groups, as well as between the low infection and intense infection groups (P < 0.05). Triglyceride levels were at their physiological limits, and differed significantly between all examined groups (P < 0.05). The results show that changes in the biochemical markers ALP, AST and ALT are related to the intensity of the Sarcocystis spp. infection.

Studies on prevalence and histomorphology of Sarcocystis species infecting cattle in Andhra Pradesh, India

The present study was carried out to determine the prevalence of bovine sarcocystosis and identify the different species of Sarcocystis cysts in cattle in different regions of Chittoor district, Andhra Pradesh. A total of 150 slaughtered cattle over a period of 1 year were examined both macroscopically and microscopically for the presence of Sarcocystis infection. Out of 150 slaughtered cattle examined, macroscopic sarcocysts were observed in nine cattle and were exclusively found in oesophagus. Examination of tissue samples collected from different predilection sites from each of 150 cattle by pepsin-HCl digestion method revealed presence of live banana shaped bradyzoites under light microscopy in 134 cattle. Six cattle that were positive by macroscopic examination were also positive by microscopic examination of tissues. The overall prevalence of Sarcocystis infection in cattle of Chittoor district was 91.33%. The prevalence of macroscopic and microscopic sarcocysts was 6.57 and 93.43% respectively. Statistically a significant relationship between the prevalence of infection among different age groups (P < 0.001) and no significant relationship (P > 0.001) between the prevalence of Sarcocystis infection in male (91.76%) and female (90.76%) cattle was observed. In both male and females the prevalence of Sarcocystis infection increased with age. Microscopically sections of tissues from cattle that were positive by tissue digestion technique revealed thin walled cysts (4.5 ± 0.5 µm) in 131 samples and thick walled cysts (0.5 ± 0.12 µm) in six cattle.

Toxoplasma gondii as a Parasite in Food: Analysis and Control

Foodborne infections are a significant cause of morbidity and mortality worldwide, and foodborne parasitic diseases, though not as widespread as bacterial and viral infections, are common on all continents and in most ecosystems, including arctic, temperate, and tropical regions. Outbreaks of disease resulting from foodstuffs contaminated by parasitic protozoa have become increasingly recognized as a problem in the United States and globally. Increased international trade in food products has made movement of these organisms across national boundaries more frequent, and the risks associated with infections have become apparent in nations with well-developed food safety apparatus in place.

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.

Modified use of methylene blue in the tissue compression technique to detect sarcocysts in meat-producing animals

Sarcocystosis in meat-producing animals is a major cause of reduced productivity in many countries, especially those that rely on agriculture. Although several diagnostic methods are available to detect sarcocystosis, many are too time-consuming for routine use in abattoirs and meat inspection centers, where large numbers of samples need to be tested. This study aimed to compare the sensitivity of the methylene blue tissue preparation, unstained tissue preparation and nested PCR in the detection of sarcocysts in tissue samples. Approximately three-fold more sarcocysts were detected in methylene blue-stained tissue compared to unstained controls (McNemar's test: P<0.01). Test sensitivity was comparable to that of the gold standard for sarcocyst detection, nested polymerase chain reaction. These results suggest that methylene blue can be used in tissue compression as a rapid, safe, and inexpensive technique for the detection of ruminant sarcocystosis in abattoirs.

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

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

Sarcocystis rommeli, n. sp. (Apicomplexa: Sarcocystidae) from Cattle (Bos taurus) and its Differentiation from Sarcocystis hominis

Cattle (Bos taurus) are intermediate hosts for three named species of Sarcocystis, S. cruzi, S. hirsuta, and S. hominis. Recently, a fourth species was identified and named S. sinensis. However, S. sinensis originally named a species of Sarcocystis in water buffalo (Bubalus bubalis) in China. Based on unverifiable evidence, it was suggested that the same parasite infects cattle. In addition, S. sinensis was recently declared as nomen nudum because its naming violated the rules of International Code of Zoological Nomenclature. Thus, the fourth species using cattle as an intermediate host does not have a valid name. Here, we propose a new name, Sarcocystis rommeli for the S. sinensis-like parasite from cattle in Argentina, and differentiate it ultrastructurally from S. hominis sarcocysts from experimentally infected cattle. Sarcocystis rommeli sarcocysts were microscopic with a 5-μm-thick wall with slender villar protrusions (Vp); the Vp were up to 5 μm long, up to 0.5 μm wide, and of uneven thickness, often bent at an angle. The ground substance layer (Gs) was up to 0.8 μm thick and smooth. Vesicular structures were seen at the base of the Vp. The bradyzoites were 10-12 μm long. Sarcocystis hominis sarcocysts had Vp that were often upright, up to 7.5 μm long, and up to 1.8 μm wide; the Gs was up to 2 μm thick and without vesicles. Its sarcocyst wall was up to 5.6 μm thick, the vp were bent at an angle, up to 5.8 μm long, the Gs was up to 2 μm thick, but without vesicles seen in S. rommeli. Beef containing sarcocysts of S. rommeli was not orally infectious for two human volunteers and a red fox (Vulpes vulpes). The Sarcocystis described here is molecularly different from S. cruzi, S. hirsuta, and S. hominis based on 18S rRNA and cox1 gene sequences.

Sarcocystis Spp. Prevalence in Bovine Minced Meat: A Histological and Molecular Study

Sarcosporidiosis is caused by ingestion of contaminated raw or undercooked bovine meat and, although considered a minor zoonosis, it can represent a threath for immunocompromised people. Aim of this study was to determine the prevalence of Sarcocystis spp. in bovine minced meat intended for raw consumption collected from butcher shops and retail stores in Turin’s province (Piedmont region, Northwest Italy). Twenty-five samples were examined in parallel by histology and polymerase chain reaction (PCR). The prevalence of infestation of Sarcocystis spp. resulted to be 64% [confidence interval (CI) 95% 42-82] and 88% (CI 95% 69-97) respectively by histology and PCR. In detail, the prevalence resulted 80% for S. cruzi (CI 95% 59-93), 68% for S. hominis (CI 95% 46-85) and 4% for S. hirsuta (CI 95% 0.10-20). The high prevalence of S. hominis highlights that sarcosporidiosis may constitute a public health problem in Italy, particularly in regions like Piedmont, that has traditional dishes prepared from raw or undercooked bovine meat.

Sarcocystis-infection of cattle in Hungary

BACKGROUND

Reports on Sarcocystis-infection of cattle are outdated or lacking in many European countries, including those in the Central-Eastern part of the continent. Therefore, to assess the prevalence of Sarcocystis spp. among bovids in Hungary, a countrywide survey was initiated. In addition, fulminant deaths of four cattle, that showed clinical signs and post mortem lesions resembling acute sarcocystiosis ("Dalmeny disease"), were investigated.

METHODS

During the countrywide survey individual heart and oesophagus samples were collected at slaughterhouses from 151 beef cattle and from 15 buffalo, kept in 31 places of Hungary. Analysis for Sarcocystis spp. was carried out with conventional PCRs for the 18S rDNA gene and gel electrophoresis, followed by sequencing of 36 strongly positive samples. Mortality cases were evaluated by histological, molecular, bacteriological and virological analyses of samples from various organs.

RESULTS

Among slaughtered cattle the rate of Sarcocystis-infection was 66%. S. cruzi was identified as the most prevalent species in aurochs-like breed, and the zoonotic S. hominis in Hungarian grey cattle. Concerning the sudden deaths of cattle, Sarcocystis-infection could not be demonstrated in organs showing haemorrhages, but S. cruzi cysts were present in the muscles. In one case "S. sinensis" was molecularly identified in the blood (indicating sarcocystaemia). Results of analyses for bacterial/viral pathogens were negative.

CONCLUSIONS

S. cruzi appears to be the most prevalent Sarcocystis sp. in cattle in Hungary, followed by the zoonotic S. hominis. However, the rate of infection with both species was shown to differ between cattle breeds. The suspected role of Sarcocystis spp. as causative agents of the fatal cases could not be confirmed.

Current status of epidemiology and diagnosis of human sarcocystosis

Species of Sarcocystis are Apicomplexan parasites requiring intermediate and definitive hosts to complete their life cycle. Humans are one of many natural host species and may serve as both intermediate and definitive hosts. However, the extent and public health significance of human Sarcocystis infection are incompletely known. In this minireview, we provide an update on the epidemiology and diagnosis of human sarcocystosis and propose some tools that could contribute to a better understanding of the clinical significance and epidemiology of Sarcocystis infections.

Sarcocystis sinensis is the most prevalent thick-walled Sarcocystis species in beef on sale for consumers in Germany

Bovines are intermediate hosts of Sarcocystis cruzi, Sarcocystis hirsuta, and Sarcocystis hominis, which use canids, felids, or primates as definitive hosts, respectively. Cattle represent also intermediate hosts of Sarcocystis sinensis, but the definitive hosts of this parasite are not yet known. Sarcocystosis in cattle is frequently asymptomatic. The infection is characterized by the presence of thin-walled (S. cruzi) or thick-walled muscle cysts or sarcocysts (S. hominis, S. sinensis, and S. hirsuta). Recent reports suggest high prevalence of the zoonotic S. hominis in beef in Europe. We therefore aimed at differentiating Sarcocystis spp. in beef offered to consumers in Germany using molecular and microscopical methods, focusing on those species producing thick-walled sarcocysts. A total of 257 beef samples were obtained from different butcheries and supermarkets in Germany and processed by conventional and multiplex real-time PCR. In addition, 130 of these samples were processed by light microscopy and in 24.6% thick-walled cysts were detected. Transmission electron microscopical analysis of six of these samples revealed an ultrastructural cyst wall pattern compatible with S. sinensis in five samples and with S. hominis in one sample. PCR-amplified 18S ribosomal DNA (rDNA) fragments of 28 individual thick-walled cysts were sequenced, and sequence identities of ≥98% with S. sinensis (n = 22), S. hominis (n = 5) and S. hirsuta (n = 1) were observed. Moreover, nine Sarcocystis sp. 18S rDNA full length gene sequences were obtained, five of S. sinensis, three of S. hominis, and one of S. hirsuta. Out of all samples (n = 257), 174 (67.7%) tested positive by conventional PCR and 179 (69.6%) by multiplex real-time PCR for Sarcocystis spp. Regarding individual species, 134 (52%), 95 (37%), 17 (6.6%), and 16 (6.2%) were positive for S. cruzi, S. sinensis, S. hirsuta, and S. hominis, respectively. In conclusion, S. sinensis is the most prevalent thick-walled Sarcocystis species in beef offered for consumption in Germany. Further studies are needed to identify the final host of S. sinensis as well as the potential role of this protozoan as a differential diagnosis to the zoonotic species S. hominis.

Different Sarcocystis spp. are present in bovine eosinophilic myositis

It has been suggested that Sarcocystis species are associated with bovine eosinophilic myositis (BEM). To date, parasite identification in this myopathy has been based on morphological techniques. The aim of the present study was to use molecular techniques to identify Sarcocystis species inside lesions of BEM. Histologically, BEM lesions of 97 condemned carcasses were examined for the presence of Sarcocystis species. Intralesional and extralesional cysts were collected using laser capture microdissection and the species was determined with a PCR-based technique based on 18S rDNA. Intralesional sarcocysts or remnants were found in BEM lesions in 28% of the carcasses. The majority (82%) of intralesional Sarcocystis species were found to be S. hominis. However S. cruzi and S. hirsuta were also found, as well as an unidentified species. It can be concluded that Sarcocystis species present in lesions of BEM are not restricted to one species.

Development of a multiplex real time PCR to differentiate Sarcocystis spp. affecting cattle

Cattle are intermediate hosts of Sarcocystis cruzi, Sarcocystis hirsuta and Sarcocystis hominis which use canids, felids or primates as definitive hosts (DH), respectively, and in addition of Sarcocystis sinensis from which the DH is unknown. The aims of the present study were to develop and optimize a multiplex real time PCR for a sensitive and specific differentiation of Sarcocystis spp. affecting cattle and to estimate the prevalence of Sarcocystis spp. in Argentinean cattle. The 18S rRNA genes from individual sarcocysts were amplified and cloned to serve as controls. For the amplification of bovine Sarcocystis spp. a total of 3 primers were used in combination with specific individual probes. Each assay was evaluated and optimized individually and subsequently combined in a multiplex assay (BovSarcoMultiplex real time PCR). The analytical specificity of the multiplex assay was assessed using 5 ng of DNA of heterologous Sarcocystis spp. and other apicomplexan parasites, and no positive reactions were observed other than for the species the PCR targeted. The analytical sensitivity ranged between 0.0125 and 0.125 fg of plasmid DNA (equivalent to the DNA of 2-20 plasmid DNA copies) or resembling DNA of 0.1-0.3 bradyzoites. A total of 380 DNA loin samples from Argentina were tested and 313, 29, 14 and 2 were positive for S. cruzi, S. sinensis, S. hirsuta and S. hominis, respectively. S. sinensis was the most prevalent species among thick walled Sarcocystis spp. in Argentinean cattle. Mixed infections were detected in 8.9% of all samples. Diagnostic sensitivity and specificity for the BovSarcoMultiplex real time PCR relative to previous microscopic examination for thin and thick-walled cyst were 91.5% and 41.7%, 36.3% and 95.9% respectively. Improved DNA extraction methods may allow to further increase the specific and sensitive detection of Sarcocystis spp. in meat samples.