Molecular-based identification of Sarcocystis hominis in Belgian minced beef

Sentinels in the shadows: Exploring Toxoplasma gondii and other Sarcocystidae parasites in synanthropic rodents and their public health implications

Synanthropic rodents play a crucial role in maintaining the life cycle of Toxoplasma gondii in anthropized regions and can serve as indicators of environmental oocyst contamination. This investigation aimed to explore the occurrence of T. gondii infection within synanthropic rodent populations using a molecular diagnostic technique targeting the 18S rDNA gene, which is generic for Coccidia, with subsequent specific PCR confirmation. We examined 97 brown rats (Rattus norvegicus), 67 black rats (R. rattus), 47 house mice (Mus musculus), and 1 common shrew (Sorex araneus). PCR tests were conducted on the brain, heart, and tongue tissues. PCR tested positive in at least one of the examined tissues in 26 R. norvegicus (26.8%), 13 R. rattus (19.4%), and 13 M. musculus (27.6%). Sequencing comparisons by BLAST allowed us to identify four different species of cyst-forming Apicomplexa. In particular, T. gondii DNA was detected in 13 (6.1%) rodents, Hammondia hammondi (including H. hammondi-like organisms) in 36 (17%) subjects, Besnoitia sp. (in two cases identified as B. besnoiti) in 8 (3.7%), and Sarcocystis gigantea in two (0.94%). Rodents from peri-urban and urban environments can act as indicators of environmental contamination by oocysts of apicomplexan parasites with cats as definitive hosts, such as T. gondii, H. hammondi, and S. gigantea, the latter of which has never been previously recorded in rodents. Moreover, the presence of B. besnoiti, a parasite with an unidentified definitive host in Europe, sheds light on the potential role of these hosts as infection sentinels.

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.

Macroscopic sarcocystosis in a pig carcass from an Italian abattoir

Different food-safety institutions, including the European Food Safety Authority, encourage monitoring and characterising Sarcocystis spp. in animals and foodstuffs; among meat-producing animals, domestic pigs (Sus scrofa domesticus) can host two different Sarcocystis spp., that is Sarcocystis miescheriana and the zoonotic Sarcocystis suihominis. Herein, we report for the first time the presence of macrocysts of Sarcocystis miescheriana in a domestic pig resulting in carcass condemnation. In North-West Italy, in June 2022 the carcass of a clinically healthy sow was condemned due to the detection of multifocal macroscopic whitish fusiform lesions. Affected muscle samples were submitted to histological and molecular analyses targeting the mtDNA cox1 and 18S rRNA genes. At gross examination and histology, well demarcated, oval or elongated macrocysts up to 8 mm in length characterized by a calcified central core surrounded by fibrosis were detected. The molecular amplification and sequencing of the cox1 mtDNA and 18S rRNA genes revealed the presence of Sarcocystis miescheriana DNA in all sampled macrocysts. Our study provides the first molecularly confirmed case of Sarcocystis miescheriana infection in a domestic pig in Italy. The present report highlights the need to increase data related to the occurrence and the prevalence of Sarcocystis spp. in meat-producing animals, and in wild and domestic pigs in particular, taking into account the zoonotic potential of Sarcocystis suihominis and the possible financial losses related to carcass discard due to macroscopic Sarcocystis spp. cysts.

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

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

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.

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.

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.

Investigation of Sarcocystis spp. in slaughtered cattle and sheep by peptic digestion and histological examination in Sulaimani Province, Iraq

Background and Aim:

Sarcocystosis is a zoonotic infection caused by various species of Sarcocystis organisms with a worldwide geographic distribution. This study investigated the presence of Sarcocystis organisms in cattle and sheep slaughtered at an abattoir in Sulaimani Province in North Iraq.

Materials and Methods:

A total of 130 muscle samples were collected during May, June, and July of 2020, including 80 samples from sheep and 50 samples from cattle. Samples were examined visually for macrosarcocysts. The peptic digestion method was used to analyze fresh muscle tissue samples for detecting microsarcocysts followed by microscopic examination. Furthermore, muscle samples were fixed and stained with hematoxylin and eosin for histopathological examination.

Results:

In the gross examination, macroscopic cysts were not detected in both cattle and sheep; hence, all the prevalence data were obtained through microscopic observation of muscle samples. The peptic digestion method revealed the presence of banana-shaped bradyzoites in 90% and 92.5% of slaughtered cattle and sheep muscle samples, respectively. Organ-wise prevalence revealed that 95% and 92% of esophageal samples of sheep and cattle contained Sarcocystis spp., respectively Moreover, 90% and 88% of sheep and cattle diaphragms were respectively infected. Histopathological examination of tissue sections revealed two morphologically distinct types of microsarcocysts, including thin-walled and thick-walled, in both sheep and cattle.

Conclusion:

The suspected Sarcocystis spp. were Sarcocystis tenella and Sarcocystis arieticanis in sheep and Sarcocystis cruzi and Sarcocystis bovifelis or Sarcocystis hominis in cattle. Infective stages of different Sarcocystis spp. are widespread in the study area environment.

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.

Sarcocystosis in Ruminants of Iran, as Neglected Food-Borne Disease: A Systematic Review and Meta-analysis

PURPOSE

Sarcocystis is a zoonotic parasitic pathogen which endangers the safety of meat and meat products. This systematic review and meta-analysis aimed to evaluate the prevalence rate and status of Sarcocystis spp. in ruminants as important food sources in Iran.

METHODS

Data were collected from papers indexed in five English language electronic databases (PubMed, Scopus, Web of Science, Science Direct, and Google Scholar) and four Persian electronic databases (IranMedex, SID, IranDoc, and Magiran) from January to April 2019. Papers were selected based on inclusion criteria. Data analysis was performed in StatsDirect statistical software, version 2.7.2.

RESULTS

The searching process resulted in the identification of 73 studies. Data analyses revealed that the total prevalence (95% confidence intervals) of Sarcocystis spp. in Iranian ruminants was 74.40% (64.01-83.56). In addition, a significant association was also observed between sarcocystosis infection in Iranian ruminants and year, host, location, and diagnostic technique (P < 0.001).

CONCLUSIONS

According to our data, the prevalence of Sarcocystis infection in ruminants is relatively high. High pathogenicity of some Sarcocystis spp. and the negative impact that the spread of some parasites among ruminants can have on human and animal health necessitate the direction of more attention toward monitoring, controlling, and preventing sarcocystosis.

Sarcocystis infection in beef and industrial raw beef burgers from butcheries and retail stores: A molecular microscopic study

Sarcocystis is a genus of eucoccidian parasites, which globally infects humans and various animals. In addition to economic losses in livestock industries, the parasite is a zoonosis that infects humans through contaminated beef and pork with the parasite sarcocysts. Therefore, this study was carried out to assess Sarcocystis contamination in beef and industrial raw beef burger samples from butcheries and retail stores in Tehran, Iran. Overall, 180 samples of 90 beefs and 90 raw industrial beef burgers with at least 80% meat were randomly collected in Tehran, Iran. Samples were studied microscopically after peptic digestion. Furthermore, sample genomic DNAs were used in conventional polymerase chain reaction (PCR) to amplify approximately 900-bp fragments from 18S ribosomal DNA. Of 180 samples, 170 samples (94.4%) were microscopically and 161 samples (89.44%) were molecularly positive for Sarcocystis spp. Eucoccidial DNA fragments were detected in 161 samples (89.4%), including 78 (86.6%) beef and 83 (92.2%) beef burger samples. No significant differences were found between the beef and beef burger infestations by Sarcocystis bradyzoites using statistical analysis (P > 0.05). Statistically significant differences were seen between the sample type and the intensity of parasites in samples (P = 0.003). Furthermore, differences between the conventional PCR results (positive/negative) and the intensity of parasites in samples were statistically significant (P < 0.001). The considerable prevalence of Sarcocystis spp. in beef and beef burger samples reflects high transmission of the parasite in meat producing cattle, which is important due to food hygiene. Although the most prevalent bovine species, S. cruzi, is not a zoonosis, it is highly recommended to follow guidelines on the parasite transmission prevention due to the existence of S. hominis as a zoonotic bovine species.

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.

Molecular identification targeting cox1 and 18S genes confirms the high prevalence of Sarcocystis spp. in cattle in the Netherlands

The reported prevalence of Sarcocystis infection in cattle in Europe ranges between 66 and 94%. Although in the Netherlands a prevalence of 100% was reported in 1993, this study aimed to develop a method for sensitive and specific molecular detection and species identification of Sarcocystis spp., in order to provide more recent data on the prevalence and identification of these protozoa in cattle meat intended for human consumption in the Netherlands. For this purpose, 104 cattle samples were obtained from Dutch slaughterhouses. Genomic DNA was extracted, and analysed by 18S and cox1 PCR. Magnetic capture was used to extract and amplify 18S-specific DNA. Sarcocystis DNA was detected in 82.7% of the samples. PCR amplicons of both targets were sequenced, and sequence identities of ≥97% were observed for Sarcocystis cruzi (65.4%), Sarcocystis hominis (12.5%), Sarcocystis bovifelis (8.7%), Sarcocystis hirsuta and Sarcocystis heydorni (both 1.0%). Mixed infections were observed in 17.3% of the samples. The magnetic capture was not significantly more sensitive compared with standard DNA extraction, but magnetic capture did add to the overall sensitivity. Using cox1 sequencing, all species are clearly distinguished, whereas for 18S the variation between species is limited, which particularly hampers reliable identification of thick walled Sarcocystis spp. Furthermore, the detection of 12.5% S. hominis and 1% S. heydorni points towards an established transmission route between cattle and humans in the Netherlands. The availability of four additional well-identified and well-referenced S. hominis cox1 sequences in public databases enables development of species-specific diagnostic PCRs targeting cox1, which in combination with magnetic capture could provide the means to determine the prevalence of human sarcocystosis.

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.

Prevalence and histopathology of Sarcocystosis in slaughtered carcasses in southeast Iran

OBJECTIVE

Sarcocystis spp. are common parasites and in terms of economics and pathogenicity in domestic animals is important. The purpose of this work was to define the rate of contamination of slaughtered carcasses of cattle to Sarcocystis using digestive and histopathological methods in southeast Iran.

MATERIAL AND METHODS

In this descriptive laboratory study for 1 year, 500 carcasses were examined and isolated bradyzoites of Sarcocystis with the digest method. Also, tissue samples from the esophagus and diaphragm were considered for pathologic studies and stained with hematoxylin and eosin of sections of histopathological.

RESULTS

The results showed that the highest contaminations were in imported male animals aged 2-3 years old in the spring. There was a significant difference (p < 0.05) in the prevalence rate with the sex and race of cattle but no significant difference (p > 0.05) in the prevalence rate with age and season.

CONCLUSION

Infection with Sarcocystis is common in oxen in this region. The imported cattle are more infected. It seems that racing and the environmental condition affect the prevalence of Sarcocystosis.

Surveillance and diagnosis of zoonotic foodborne parasites

Foodborne parasites are a source of human parasitic infection. Zoonotic infections of humans arise from a variety of domestic and wild animals, including sheep, goats, cattle, camels, horses, pigs, boars, bears, felines, canids, amphibians, reptiles, poultry, and aquatic animals such as fishes and shrimp. Therefore, the implementation of efficient, accessible, and controllable inspection policies for livestock, fisheries, slaughterhouses, and meat processing and packaging companies is highly recommended. In addition, more attention should be paid to the education of auditors from the quality control (QC) and assurance sectors, livestock breeders, the fishery sector, and meat inspection veterinarians in developing countries with high incidence of zoonotic parasitic infections. Furthermore, both the diagnosis of zoonotic parasitic infections by inexpensive, accessible, and reliable identification methods and the organization of effective control systems with sufficient supervision of product quality are other areas to which more attention should be paid. In this review, we present some examples of successful inspection policies and recent updates on present conventional, serologic, and molecular diagnostic methods for zoonotic foodborne parasites from both human infection and animal‐derived foods.

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.

Molecular identification of Sarcocystis species in raw hamburgers using PCR-RFLP method in Kashan, central Iran

The prevalence of bovine Sarcocystosis is high in the most regions of the world. It can be a human health problem due to consumption of raw or under cooked hamburgers or other bovine meat products. This study was carried out to investigate the prevalence and species identification of Sarcocystis among of hamburgers, using PCR-RFLP methods in Kashan, central Iran. Overall 200 raw industrial hamburgers samples with at least 60% meat were randomly collected from nine different brands in Kashan, central Iran. The genomic DNA was extracted and a PCR-RFLP method was used to amplify an approximately 900 bp fragment at the 18S rRNA(SSU) gene, restriction enzyme BclI was used for species identification. The results showed that 58 (29%) of 200 tested hamburger samples were infected to Sarcocystis spp. The prevalence rate was 31.25 and 26.9% in the hamburgers with 90 and 60-75% meat, respectively. According to PCR-RFLP analysis, 43 (74.1%) of the 58 isolates were Sarcocystis cruzi, 12 (20.7%) showed co-infection to S. cruzi and Sarcocystis hirsuta, 2 (3.5%) was mixed infected to S. cruzi and Sarcocystis hominis, 1 (1.7%) showed the pattern of mix infection to three species. This study revealed one-third of industrial hamburger were infected to S. cruzi or mixed infection of S. cruzi with other bovine sarcocytosis. To prevent cattle infection, the possible ingestion of the disposal sporocyst stage from dogs must be eliminated. Although in this study, the prevalence of S. hominis was low and cannot be considered as a major zoonosis, it should be recommended avoiding eating under cooked hamburger and other bovine meat products to prevent human infection.

Molecular differentiation of bovine sarcocysts

Cattle are common intermediate hosts of Sarcocystis, and the prevalence in adult bovine muscle is close to 100 % in most regions of the world. Three Sarcocystis spp. are known to infect cattle as intermediate hosts, namely, S. cruzi, S. hirsuta, and S. hominis. The aim of the present study was the molecular identification and differentiation of these three species, Neospora caninum and Besnoitia by PCR and RFLP methods. Tissue samples were obtained from diaphragmatic muscle of 101 cattle slaughtered in Shiraz, Fars Province, Iran, for both smear preparation and DNA extraction. The samples were digested by Pepsin, washed three times with PBS solution before taking smears, fixed in absolute methanol and stained with 10 % Giemsa. The slides were examined microscopically for Sarcocystis bradyzoites and DNA was extracted from 100 mg of Sarcocystis-infected meat samples. Since the primers also bind to 18S rRNA gene of some tissue cyst-forming coccidian protozoa, DNA was also extracted from 100 μl of tachyzoite-containing suspension of N. caninum and Besnoitia isolated from goat to compare RFLP pattern. Polymerase chain reaction (PCR) was performed on DNA of samples which were microscopically positive for Sarcocystis. Five restriction enzymes Dra1, EcoRV, RsaI, AvaI, and SspI were used for RFLP and DNA of one sample from protozoa was sequenced. Based on the RFLP results, 87 (98.9 %) DNA samples were cut with DraI, indicating infection by S. cruzi. One sample (1.1 %) of PCR products of infected samples was cut only with EcoRV which showed S. hominis infection. Forty-eight samples (53.3 %) of PCR products were cut with both DraI, EcoRV, or with DraI, EcoRV, and RsaI while none of them was cut with SspI, which shows the mixed infection of both S. cruzi and S. hominis and no infection with S. hirsuta. It seems by utilizing these restriction enzymes, RLFP could be a suitable method not only for identification of Sarcocystis species but also for differentiating them from N. caninum and Besnoitia.

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.

Detection of sarcocystosis in goats in Malaysia by light microscopy, histology, and PCR

A number of methods have been used for the detection of the presence of microsarcocysts in animals, but little information exists on the value between the various methods. This study therefore examined for Sarcocystis spp. using three different methods in 105 samples of skeletal muscle collected from goats slaughtered in an abattoir in Selangor, Malaysia from January to February 2014. Three methods were used, direct light microscopy of squashed fresh muscle tissues; histological examination of fixed, sectioned, and hematoxylin and eosin (H&E)-stained samples of muscle; and molecular identification by polymerase chain reaction (PCR). Of the 105 tissue samples, 55 (52.38 %) were positive by light microscopy (LM), 46 (43.8 %) by histology, and 95 (90.48 %) by PCR. Only 29 (27.6 %) and 5 (4.76 %) samples were positive and negative, respectively, by all three methods. The cysts were elongated to a spindle shape with a mean size of 393.30 × 81.6 μm and containing banana-shaped bradyzoites of size 12.32 × 2.08 μm. The wall of the cyst was radially striated with a thickness of 2.83 μm. Samples were tested for the presence of Sarcocystis-specific 18S rRNA and were identified as Sarcocystis capracanis. Of the three methods used, the PCR test appears to be the most useful method for the diagnosis of sarcocystosis especially for species identification.

A survey on Sarcocystis spp. infection in cattle of Tabriz city, Iran

Sarcocystis is one of the most prevalent protozoan parasites in the striated muscles of livestock slaughtered for food such as cattle, sheep and goat. Meat that is heavily infected may be condemned as unfit for human consumption. The aim of this study was to determine the prevalence of Sarcocystis spp. in slaughtered cattle in Tabriz, northwest of Iran. The prevalence of Sarcocystis spp. infection was investigated in 670 cattle, slaughtered from April 2013 to October 2013 in the Tabriz abattoir, Iran using naked eye examination for macroscopic Sarcocysts, and peptic digestion, muscle squash, squeezing methods for microscopic types. Muscles from oesophagus, tongue, heart, diaphragm and cervical and abdominal of 670 slaughtered cattle were examined for Sarcocystis spp. cysts. The prevalence of microscopic Sarcocystis spp. cysts in cattle was detected in 100 % and there was detected in macroscopic cyst 8.2 % in examined cattle. There were no significant differences among the infection rates of the different organs (P > 0.05). There were no significant differences among the infection rates of the different ages (P > 0.05). The prevalence of macroscopic infection in the oesophagus was higher than that of the other organs (P < 0.05). The infection rate was independent of sex (8.25 % in males and 8.13 % in females, P > 0.05). This suggests that meat should be cooked sufficiently, since a macroscopic inspection may not provide true results. Also, it has of great importance the farmers to be trained not to feed their dogs and cats with uncooked meat, and the abattoir remnants to be burned, in order to be effectively broken of infection cycle between the intermediate and the definitive hosts in Tabriz city, northwest of Iran.

The role of sheep in the epidemiology of Sarcocystis spp. in Tabriz area northwest of Iran

The parasites of genus Sarcocystis are among the most commonly found parasites in domestic ruminants and some species of Sarcocystis can generate important economic loss when causing clinical and subclinical disease. In the present study, three techniques-direct inspection, impression smears and digestion method-were used for the diagnosis of Sarcocystis infection in 130 slaughtered sheep in Tabriz abattoir from April 2013 to October 2013. A total of 620 slaughtered sheep were selected randomly and their oesophagus and diaphragm were inspected using naked eye examination. In the second stage, 130 carcasses out of the 620 which had no apparent infection were selected randomly and their meat investigated using two techniques: impression smear with staining and pepsin digestion. The percentage of macroscopic cysts found in the oesophagus and diaphragm muscle was 5.64 and 2.74 %, respectively, and microscopically, infection was found in 100 % of the organs. There was no significant difference between different ages or between males and females. Although all of the sheep were found to be infected with Sarcocystis, majority of the cysts were demonstrated microscopically. This suggests that meat should be cooked sufficiently, since a macroscopic inspection may not provide true results. Also, it has of grea t importance the farmers to be trained not to feed their dogs and cats with uncooked meat, and the abattoir remnants to be burned, in order to be effectively broken of infection cycle between the intermediate and the definitive hosts in Tabriz city, northwest of Iran.

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.

Prevalence and histopathological finding of thin-walled and thick-walled Sarcocysts in slaughtered cattle of Karaj abattoir, Iran

Sarcocystosis is a zoonotic disease caused by Sarcocystis spp. with obligatory two host life cycle generally alternating between an herbivorous intermediate host and a carnivorous definitive host. Some species of this coccidian parasite can cause considerable morbidity and mortality in cattle. The present study was set to investigate the prevalence of Sarcocystis spp. and type of cyst wall in slaughtered cattle of Karaj abattoir, Iran. For this purpose 125 cattle (88 males and 37 females) were investigated for the presence of macroscopic and microscopic Sarcocystis cysts in muscular tissues. No macroscopic Sarcocystis cysts were found in any of the samples. In light microscopy, 121 out of 125 cattle (96.8 %) had thin-walled cysts of Sarcocystis cruzi, while 43 out of them (34.4 %) had thick-walled Sarcocystis cyst. In this survey, the most infected tissue was esophagus and heart and the less was diaphragm. Thin-walled cysts (S. cruzi) mostly found in heart and skeletal muscle showed the less. However, thick-walled cyst (S. hominis or S. hirsuta) mostly were detected in diaphragm, heart muscle showed no thick-walled cyst. No significant relation was observed between age and sex and the rate of infection. The results showed that Sarcocystis cyst is prevalent in cattle in the North part of Iran and the evaluation of infection potential can be useful when considering control programs.

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.

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

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

Low predictive value of seroprevalence of Toxoplasma gondii in cattle for detection of parasite DNA

The role of beef in human infections with Toxoplasma gondii is not clear. To get a better understanding of the value of seroprevalence as an indication of the role of beef in human infections with T. gondii we studied the seroprevalence of T. gondii in Dutch cattle and analysed the correlation between detection of antibodies and parasitic DNA. An indirect ELISA was developed and used to test a sample of the Dutch cattle population. Since validation of the ELISA was hampered by a lack of sufficient bovine reference sera, the results were analysed in two different ways: using a cut-off value that was based on the course of the OD in 27 calves followed from birth until 16 months of age, and by fitting a mixture of two normal distributions (binormal mixture model) to the log-transformed ODs observed for the different groups of cattle in the study population. Using the cut-off value, the seroprevalence was estimated at 0.5% for white veal, 6.4% for rosé veal and 25.0% for cattle. However, using the frequency distributions the prevalences were higher: 1.9% for white veal, 15.6% for rosé veal and 54.5% for cattle. Next, for 100 cattle the results with two different serological assays (ELISA and Toxo-Screen DA) were compared with detection of parasites by our recently developed sensitive magnetic capture PCR. Toxoplasma gondii DNA was detected in only two seronegative cattle. This discordance demonstrates that seroprevalence cannot be used as an indicator of the number of cattle carrying infectious parasites. Demonstrating parasitic DNA in seronegative cattle and not in seropositive cattle suggests that only recent infections are detectable. Whether beef from these PCR-positive cattle is infectious to humans remains to be studied.

Development of a biomolecular assay for postmortem diagnosis of Taenia saginata Cysticercosis

Bovine cysticercosis is caused by the larval stage of the human tapeworm Taenia saginata. According to European data on meat inspection, the prevalence ranges from 0.007% to 6.8%, but the real prevalence is considered to be at least 10 times higher. Laboratory confirmation of the etiological agent is based on gross, stereomicroscopic, and histological examination of submitted specimens. False identifications may occur, possibly because of death and degeneration of cysts, or because taeniid larvae and other tissue parasites, such as Sarcocystis spp., may cause similar macroscopic morphological lesions. Therefore, tests that can warrant sure identification of taeniid lesions and calcified cysts in the muscle are needed. The focus of our study was to develop a suitable postmortem test that could be applied on putative lesions by T. saginata cysticerci, as ambiguously diagnosed after routine meat inspection. In particular, we proposed a biomolecular assay targeting the mitochondrial cytochrome c oxidase subunit I gene (COI). For developing the polymerase chain reaction assay, viable cysts of Cysticercus bovis (n = 10) were used as positive reference samples, and those of Echinococcus granulosus (n = 3), Cysticercus tenuicollis (n = 3), and Sarcocystis spp. (n = 4) as reference negative controls. Further, to evaluate the applicability of the proposed assay, 171 samples of bovine muscular tissue, obtained from local slaughterhouses and containing lesions recognized as T. saginata cysticerci by macroscopic examination, were tested. The proposed test confirmed the diagnosis at postmortem inspection in 94.7% (162/171) of samples. In conclusion, the assay developed in this study, amplifying a short fragment from the mitochondrial gene COI, showed to be suitable for samples containing both viable and degenerating T. saginata cysticerci, yielding an unequivocal diagnosis.

Prevalence of thin-walled Sarcocystis cruzi and thick-walled Sarcocystis hirsuta or Sarcocystis hominis from cattle in Iran

Bovine sarcocystosis is caused by Sarcocystis cruzi and is known to cause considerable morbidity and mortality in cattle. This species is distributed worldwide in cattle and is the most prevalent of the Sarcocystis species infecting cattle. There is high infection rate of sarcocyst in cattle in Iran, but to our knowledge, there is no study about identification of Sarcocystis species. This work aimed to survey prevalence of S. cruzi cyst in slaughtered cattle of Isfahan, Iran. In this study, esophageal and diaphragmatic muscles of 100 cattle were collected from Fesaran abattoir of Isfahan and examined for the presence of Sarcocystis spp. cysts macroscopically and microscopically. No macroscopic sarcocysts were found in any of the samples. In light microscopy, 89 out of 100 cattle (89%) had thin-walled cysts of S. cruzi, while 21 out of them (21%) had thick-walled sarcocysts. In addition to light microscopy, ultrastructural features of the thin-walled cyst confirmed the presence of S. cruzi.

Evidence-based semiquantitative methodology for prioritization of foodborne zoonoses

OBJECTIVES

To prioritize an extended list of food- and water-borne zoonoses to allow food safety authorities to focus on the most relevant hazards in the food chain.

METHODS

An evidence-based semiquantitative methodology was developed. Scores were given by 35 scientific experts in the field of animal and public health, food, and clinical microbiology and epidemiology to 51 zoonotic agents according to five criteria related to public health (severity and occurrence in humans), animal health (severity of disease coupled with economic consequences and occurrence in animals), and food (occurrence in food). The scoring procedure was standardized and evidence-based as experts were provided, for each zoonotic agent, a same set of up-to-date help information data related to the five criteria. Independently, the relative importance of the five criteria was weighted by seven food chain risk managers. The zoonotic agents were ranked based on overall weighted scores and were grouped in four statistically different levels of importance.

RESULTS

The following foodborne zoonotic pathogens were classified as "most important": Salmonella spp., Campylobacter spp., Listeria monocytogenes, and verocytotoxigenic Escherichia coli. A second group of "significant importance" included Toxoplasma gondii, the agent of bovine spongiform encephalopathy, Clostridium botulinum, Staphylococcus aureus, Cryptosporidium parvum, Mycobacterium bovis, Echinococcus granulosus, Streptococcus spp., Echinococcus multilocularis, Yersinia enterocolitica, Mycobacterium avium, Fasciola hepatica, Giardia intestinalis, and Rotavirus.

CONCLUSIONS

This methodology allowed to rank 51 zoonotic agents with objectivity and taking account of a combined input from risk assessors and risk managers.

APPLICATIONS

These results support food safety policy makers to establish the multiannual monitoring program of foodborne zoonoses. They also enable to identify knowledge gaps on specific zoonotic agents and to formulate key research questions. Principally, this method of prioritization is of general interest as it can be applied for any other ranking exercise and in any country.

Detection of sarcocystis parasites in retail beef: a regional survey combining histological and genetic detection methods

Sarcocystis spp. are parasitic protists acquired when undercooked, cyst-laden meat is consumed. While both Sarcocystis hominis and S. cruzi encyst in beef, only S. hominis is pathogenic to humans. In this study, we used histological methods and novel molecular techniques to determine the regional prevalence and identity of Sarcocystis spp. in retail beef. Of 110 samples, 60 supported amplification of parasite rRNA by PCR. All 41 sequenced representatives were identified as S. cruzi. To compare detection methods, 48 samples were then examined in parallel by histology and PCR, and 16 and 26 samples, respectively, were positive. Five samples positive by initial histologic sections were not amplified by PCR. Fifteen PCR-positive samples did not contain sarcocysts on initial histologic section, but additional sections from these samples revealed sarcocysts in an additional 12 samples. When combined, histology with additional sections and PCR detected 31 positive specimens of the 48 total specimens. We found no evidence of human pathogen S. hominis and confirm that cattle pathogen S. cruzi is highly prevalent in this regional sample. PCR assays may increase the detection sensitivity of Sarcocystis spp. and contribute diagnostic precision.