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

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

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

Molecular identification of Sarcocystis species in wild boar (Sus scrofa) and pigs (Sus scrofa domesticus) in Brazil

Sarcocystis spp. are protozoan parasites that form cysts in the organs and musculature of various animal species. The species Sarcocystis miescheriana and Sarcocystis suihominis are pathogenic to pigs and wild boars (Sus scrofa), acting as intermediate hosts, while humans are the definitive host for S. suihominis. To date, there have been no reports of the identification of these coccidian species in Sus scrofa in Brazil. Therefore, in this study, we conducted the first molecular identification of Sarcocystis species using PCR-RFLP and sequencing. A total of 210 samples were analyzed, of this total, 67 tested positive for Sarcocystis spp., representing 31.9% of the total samples assessed. Out of the total positive samples, 55 (82.1%) were identified as S. miescheriana and 8 (11.9%) as S. suihominis, a zoonotic species. Additionally, other species related to bovines, such as S. cruzi and zoonotic S. hominis, were detected in 3.0% of the samples, serving as contaminants in the pork products. The presence of S. suihominis in swine and wild boar samples is concerning due to the zoonotic risk and potential environmental contamination, as humans act as definitive hosts, also for the presence of S. hominis as a bovine contaminant in pork sausages. Furthermore, we confirmed the efficacy of the PCR-RFLP technique as a reliable tool for the identification of Sarcocystis species, demonstrating its potential use in laboratories for molecular diagnosis and rapid identification of these parasites, aiming to protect public health and ensure food safety.

Molecular identification of Sarcocystis neurona in tissues of wild boars (Sus scrofa) in the border region between Brazil and Uruguay

Sarcocystis neurona, owing to its clinical importance in domestic animals, is currently one of the most studied agents, presenting a wide range of intermediate hosts that have not yet been described, mainly in wild fauna. Thus, the aim of this study was to describe the detection and molecular detection of S. neurona by amplification of the 18S rRNA region in the tissues of wild boars killed by boar control program in border Brazil Uruguay. A total of 79 samples of DNA from wild boar tissues from the LADOPAR/UFSM sampling bank were used, with Nested-PCR reactions being performed for amplification of the 18S rRNA region and the expected final product of 290 bp. Subsequently, the positive samples were subjected to restriction fragment length polymorphism (RFLP) technique with the restriction enzymes DdeI and HPAII. A second semi-Nested reaction was performed to obtain a larger sequence of nucleotides with amplification of the 18S region and the expected final product of 500 bp for S. neurona and Nested amplification ITS1 with product final of 367 pb. In 32 samples, it was possible to detect S. neurona both by nested Nested-PCR reaction and RFLP, and the presence of the agent was confirmed by sequencing, corresponding to 40.51% of the total tissues evaluated. This is the first report of the occurrence of this species of Sarcocystis in wild boars, and further studies evaluating the role of these animals as intermediate hosts, and in the epidemiology of this protozoan are necessary, as well as verifying the risk factors for infection.

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

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

Sero-epidemiological investigation on Toxoplasma gondii infection in Apennine wolf (Canis lupus italicus) and wild boar (Sus scrofa) in Italy

BACKGROUND

The wild boar (Sus scrofa) and the Apennine wolf (Canis lupus italicus) are two wild species that have both increased their presence in the Italian territory, albeit in varying numbers. They can be occasionally found in peri-urban areas as well. Both of these species can serve as intermediate hosts for Toxoplasma gondii, as they can become infected either through the consumption of oocysts found in water, soil, or on vegetables, or through the ingestion of meat containing bradyzoites. Consequently, these animals can be regarded as key indicators of Toxoplasma presence in the wild or peri-urban environment. In our study, we examined a total of 174 wild boar meat juice and 128 wolf sera from Italy for the detection of T. gondii IgG using the indirect fluorescent antibody test (IFAT).

RESULTS

The results showed that 40 (22.6%) of the wild boar meat juice and 34 (26.6%) of the wolf serum samples tested positive. Interestingly, there were no significant differences in seropositivity with respect to gender, age group, or the region of origin in both species.

CONCLUSIONS

Overall the results indicate a moderate exposure in both the species under investigation, highlighting the spread of T. gondii in sylvatic and periurban environments. The prevalence of T. gondii in wild boar is consistent with findings from other studies conducted in Europe. Our study, with a considerably larger sample size compared to the available research in European context, provides valuable data on the seroprevalence of T. gondii in wolves.

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.

Molecular identification of Sarcocystis species in sika deer (Cervus nippon) of free-ranging populations in Germany and Austria

In this study, for the first time, Sarcocystis species were identified molecularly in sika deer (Cervus nippon) that form free-ranging populations in several countries of Europe. Diaphragm muscle samples from 151 deer from 10 populations in Germany and Austria were examined for sarcocysts. By one-gram methylene-blue staining, sarcocysts were recorded in samples of 114 animals (75.5%) which originated from all populations. Sarcocysts were more often (p < 0.0001) recorded in yearling and adult deer than in calves. Infection intensity was generally low with ~ 70% of the sarcocyst positive deer harbouring ≤ 10 sarcocysts per 1-gram diaphragm muscle. Based on cox1 sequence comparison, 10 species of Sarcocystis, all previously reported parasitizing cervids, were identified: S. elongata, S. entzerothi, S. hjorti, S. iberica, S. japonica, S. linearis, S. morae, S. pilosa, S. silva and S. truncata. The prevailing S. hjorti was detected in sika deer of all 10 populations. The identification in sika deer of S. hjorti, S. iberica, S. elongata, S. linearis, S. morae and S. silva constitutes new host records. With the additional species records of this study, the highest number of Sarcocystis species, at least 16, was identified in this host.

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

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

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

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

Serological Prevalence of Toxoplasma gondii, Neospora caninum, and Sarcoptes scabiei var. suis in Wild Boars (Sus scrofa) Hunted in a Highly Anthropized Area in Italy

Due to the increasing expansion into urban and rural areas, wild boars represent a potential source of infection with zoonotic and animal-specific parasites for both humans and animals. Therefore, the aim of this study was to investigate the serological prevalence to Toxoplasma gondii, Neospora caninum, and Sarcoptes scabiei var. suis in blood samples from wild boars (Sus scrofa) hunted in an anthropized area in Italy. Enzyme-linked immunosorbent assay (ELISA) tests were used to detect antibodies anti-T. gondii and anti-S. scabiei and an immunofluorescence antibody test (IFAT) for antibodies anti-N. caninum. 81 out of 128 wild boars (P = 63.3%) resulted positive for at least one of the three parasites. 68 of them were seropositive to T. gondii (P = 53.1%) and 14 to N. caninum (P = 10.9%). 9 wild boars resulted seropositive to S. scabiei var. suis (P = 7.0%). Sampling season was the only significant risk factor related to S. scabiei var. suis seroprevalence (OR = 7.8). The high occurrence of T. gondii supports the role of this species as a source of infection for other animals and humans. Furthermore, the serological prevalence of N. caninum and S. scabiei var. suis in wild boars from the study area characterized by the presence of numerous dairy cattle and pig farms is relevant to demonstrate its suitability for the circulation of these parasites both in domestic and wild species.

First report of Sarcocystis spp. (Apicomplexa, Sarcocystidae) in Lagostomus maximus (Desmarest, 1917) (Rodentia, Chinchillidae) in Argentina

Sarcocystis is a genus of intracellular parasitic protozoa that infects various species of mammals, birds, and reptiles worldwide. At least 46 Sarcocystis species naturally infect rodents as intermediate hosts producing tissue cysts. This study aimed to provide the first report and molecular characterisation of Sarcocystis spp. in muscles from plains viscacha (Lagostomus maximus) in Argentina. Muscle samples of 53 plains viscachas from three provinces of Argentina were processed by homogenisation and optical microscopy to detect tissue cysts. Positive samples were analysed by PCR-sequencing, using the following markers: 18S rRNA, ITS1, and coxI. The 18S rRNA and coxI consensus sequences were aligned with other sequences from Sarcocystis spp., and phylogenetic trees were constructed. Of all animals processed, 13.2% (7/53) harboured Sarcocystis sp. cysts. 18S rRNA consensus sequences were obtained from four muscle samples and one individual cyst, and they showed 99.88-100% similarity, except for the cyst sequence, which showed 97.11% homology. Similarities of only 96-97% were recorded in the 18S rRNA fragment with other Sarcocystis spp. whose sequences are available in the GenBank. The five coxI fragment sequences obtained were 100% identical and showed an identity of 99.41-99.48% with S. canis. For ITS1 only short and low-quality sequences were obtained. In the phylogenetic trees, all the sequences from plains viscachas were positioned together in a branch separated from other Sarcocystis spp. These results could be related to new Sarcocystis spp. producing sarcocysts in plains viscachas. Besides, comprehensive cyst morphological analysis using TEM from the new Sarcocystis species will allow a description of the cyst wall ultrastructure. In this sense, further studies are needed to deepen these findings and elucidate other potential intermediate and possible definitive hosts.

Prevalence of Eucoleus garfiai in Wild Boars Hunted at Different Altitudes in the Campania and Latium Regions (Italy)

Recent reports of Eucoleus garfiai in wild boars in southern Italy have highlighted the need for collecting epidemiological data on the presence of this parasite and understanding the role of possible interactions between wild boars, E. garfiai, and the environment. This study analyses, using histopathological and biomolecular techniques, the presence of E. garfiai in tongue samples of wild boars hunted in four provinces of the Campania and Latium regions (Italy), in areas located above and below 900 m above sea level (asl). Histopathological examinations revealed the presence of adults and eggs of nematodes, which were subsequently identified as E. garfiai by biomolecular analysis, in the tongue epithelium. The detection of the parasite was more frequent in samples collected from hunting areas located above 900 m asl than in those collected from areas located below 900 m asl (66.67% vs. 38.09%; p < 0.01). Some species of earthworms are intermediate hosts of E. garfiai and it is well known that earthworms are more present in high quality soils. Therefore, we can suggest that the higher prevalence of E. garfiai at higher altitudes is probably linked to a greater presence of earthworms in the soil, due to its higher quality in these areas.

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

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

Molecular Identification of Protozoan Sarcocystis in Different Types of Water Bodies in Lithuania

Representatives of the genus Sarcocystis are unicellular parasites having a two-host life cycle and infecting mammals, birds, and reptiles. Until now, Sarcocystis spp. have been mainly investigated in definitive and intermediate hosts. Only a few studies have been conducted on the detection of Sarcocystis parasites in water samples. The aim of this research was to examine whether the prevalence of Sarcocystis spp. parasitizing farm animals varies in different types of water bodies. Water samples (n = 150) were collected from the entire territory of Lithuania, dividing water bodies into five groups (lakes, rivers, ponds/canals, swamps, and the inshore zone of the territorial Baltic Sea area). One-liter samples were filtered and subsequently analyzed using nested PCR. At least one of the analyzed Sarcocystis spp. (S. arieticanis, S. bertrami, S. bovifelis, S. capracanis, S. cruzi, S. hirsuta, S. miescheriana, and S. tenella) was determined in all examined samples from water bodies. No significant difference in Sarcocystis spp. prevalence between different types of water sources was detected. Our research proved that selecting appropriate primers is important for the accurate identification of parasites in samples collected from water bodies.

Prevalence of Neospora caninum antibodies in fattening pigs and sows from intensive farms in northern Italy

Neospora caninum (Apicomplexa, Sarcocystidae) is a major cause of reproductive failure in cattle. In pigs, only a few studies investigated the effects of this parasite on reproductive efficiency. Considering the relevance of swine farms in northern Italian regions, an epidemiological survey was designed to investigate the spread of N. caninum infection. Three hundred seventy fattening pigs and sows from 23 intensive farms in Lombardy were sampled. Sera were analyzed by a commercial immunofluorescence antibody test. Statistical analysis through univariate and multivariate generalized linear models was conducted to detect farm management practices enhancing the risk of infection. At the farm level, 52.1% (12/23) of the selected farms, 72.7% housing sows and 40% fattening pigs, scored positive. At the individual level, 25 animals (25/370, P = 6.7%) were positive to N. caninum antibodies: one fattening pig and two sows showed an antibody titer of 1:100, and in two sows, an antibody titer of 1:400 and 1:6400 was evidenced. A higher seroprevalence was detected in sows (17/151, P = 11.2%) if compared to fattening pigs (8/219, P = 3.6%) (OR = 1.19, P value = 0.000 in sows). Moreover, a higher seroprevalence was recorded in farms with low and moderate sanitary score (P = 100% and P = 64.2%, respectively) if compared to farms with high sanitary score (P = 22.2%) (OR = 1.24, P value = 0.007 in score = 1 and OR = 1.10, P value = 0.050 in score = 2). This study provides the first data on the circulation of N. caninum in intensive swine farms in Italy, demonstrating the spread of the parasite in fattening pigs and sows in Lombardy region.

A Review on Alaria alata, Toxoplasma gondii and Sarcocystis spp. in Mammalian Game Meat Consumed in Europe: Epidemiology, Risk Management and Future Directions

Simple Summary

In many European countries, game meat consumption is related to the traditional hunting culture. Its demand and consumption are increasing, also due to the growing populations of wild ungulates. However, specific public health issues exist and should be taken into account. This review focuses on the causal agents, epidemiology, potential risk for human health and its management along the supply chain, including parasite detection at slaughtering and inactivation in meat, of three parasites (Alaria alata, Toxoplasma gondii and Sarcocystis spp.), which can be transmitted by the main mammalian game meat species in the EU: wild boar (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), Alpine chamois (Rupicapra rupicapra), moose (Alces alces), hare (Lepus europaeus) and wild rabbit (Oryctolagus cuniculus). By presenting the main issues and knowledge gaps, this study aims to contribute to an improved control supporting the risk analysis process.

Abstract

Game meat is increasingly appreciated and consumed in Europe, also due to the growing population of wild ungulates. In addition to interesting nutritional properties and market opportunities, game meat is characterized by some specific public health issues. This review focuses on the etiology, epidemiology, public health aspects and risk management along the supply chain, including parasite detection at slaughtering and inactivation in meat, of three selected foodborne parasitic hazards (Alaria alata, Toxoplasma gondii and Sarcocystis spp.) in the main mammalian game meat species in the EU: wild boar (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), Alpine chamois (Rupicapra rupicapra), moose (Alces alces), hare (Lepus europaeus) and wild rabbit (Oryctolagus cuniculus). The presented data point out the main issues, and knowledge gaps as well as the potential for improved control in order to contribute to the risk analysis process. To pursue an effective management of these parasitic zoonoses, awareness raising should involve all figures in the supply chain, including hunters, restaurateurs and consumers. Human behaviour and the lack of knowledge regarding meat borne parasitic zoonoses and the health risks they pose seem to be the most important factors responsible for human infections. However, detection methods, starting from the sampling procedure, should be further developed and standardized in order to improve the collection of accurate and up-to-date epidemiological data.

Raw meat based diet (RMBD) for household pets as potential door opener to parasitic load of domestic and urban environment. Revival of understated zoonotic hazards? A review

RMBD (acronym of Raw Meat Based Diet) and BARF diets (acronym for Biologically Appropriate Raw Food or Bones and Raw Food) account dietary regimens based on raw ingredients (including raw meat), popular in pet feeding. Animal tissues and organs as well as other uncooked ingredients are more and more popularly used by pet owners to feed household pets. However, the increased risk of exposure to microbiological and parasitic agents poses the question as to whether such diets may be recommendable to be handled and offered to domestic cats and dogs co-living in domestic and urban environment. Above all, the threat of human and animal infections by parasites from raw meat fed to pets is not sufficiently explored and tracked, meanwhile deserving particular surveillance, instead. At this regard, raw meat feeding to pets may represent a route of exposure to the increased risk of environmental load. In fact, some parasites typically found in rural environment can be given the chance to complete their life-cycle, for the closeness between definitive and intermediate hosts. This is of particular concern, as potentially infected pets serving as definitive hosts can become a continuous source of environmental diffusion of parasites, both at domestic and urban level. The handling of raw meat requires adequate knowledge and awareness of the hygienic principles to prevent the onset of disorders related to both manipulation by pet owners and uncooked food consumption by the pet. This review aimed to shed a comprehensive overview of the hygienic aspects related to raw pet feeding, as to handling of raw meat in domestic environment, with special emphasis on parasitic agents and related zoonotic hazards.

Spatial distribution of anti-Toxoplasma gondii antibody-positive wild boars in Gifu Prefecture, Japan

Toxoplasma gondii is a globally wide-spread parasite that infects almost all species of mammals and birds, including humans. We studied the spatial distribution of individual T. gondii-seropositive wild boar in Gifu Prefecture (10,621 km²), Japan. Altogether, 744 wild boars were captured at 663 points around human settlements in Gifu Prefecture. Serum samples were collected after recording the exact capture locations, along with each wild boar’s body length and sex. We then used a commercial enzyme-linked immunosorbent assay kit for swine to measure anti-T. gondii antibodies in these animals. Among the 744 wild boars, 169 tested positive for T. gondii (22.7%). No significant difference in T. gondii seroprevalence was observed between the mountainous northern region with high winter snow cover and the mild-wintered geographical plain of the southern part of the prefecture. In contrast, 8 of the 11 wild boars that were captured in a public park surrounded by residential areas showed T. gondii seropositivity (72.7%), a value significantly higher than those of the wild boar populations in the other prefecture areas. This in-depth analysis, which spans the big city suburbs and rural areas of a whole prefecture, explains the seroprevalence of zoonotic T. gondii in wild boar and has public health implications.

Molecular identification of seven Sarcocystis species in red deer (Cervus elaphus) from Lithuania

The diaphragm muscles of 77 free-ranging red deer (Cervus elaphus) were examined for Sarcocystis species in Lithuania. Sarcocysts were detected in 61 out of 77 (79.2%) animals investigated. A total of 60 isolated sarcocysts were identified to species using subunit I of cytochrome c oxidase (cox1) sequence analysis. Overall, seven species, S. entzerothi, S. hjorti, S. iberica, S. linearis, S. pilosa, S. truncata and S. venatoria, were confirmed in Lithuanian red deer. Sarcocystis entzerothi was reported in red deer for the first time. Previously this species was shown to use sika deer as well as roe deer and fallow deer as an intermediate host. Based on cox1, with the addition of the current data, altogether 13 Sarcocystis species have so far been shown to use red deer as an intermediate host. Species detected in red deer demonstrated considerable differences in intraspecific genetic variation at cox1. Genetic distances between different samples of S. hjorti and S. linearis were calculated using principal coordinates analysis (PCoA), implying molecular divergence of same Sarcocystis species using different hosts in the same geographical area and divergence of those employing same intermediate host species from different areas.

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.

Sarcocystis infection in red deer (Cervus elaphus) with eosinophilic myositis/fasciitis in Switzerland and involvement of red foxes (Vulpes vulpes) and hunting dogs in the transmission

Red deer (Cervus elaphus) carcasses showing grey-greenish discolouration have been increasingly observed in the canton of Grisons, Switzerland. We investigated whether Sarcocystis infections were associated with this pathology, and whether wild and domestic canids were involved in their transmission. Meat from affected red deer (n = 26), faeces and intestines from red foxes (Vulpes vulpes) (n = 126), and faeces from hunting dogs (n = 12) from the region, were analysed. Eosinophilic myositis and/or fasciitis were diagnosed in 69% of the deer, and sarcocysts were observed in 89% of the animals. Molecular typing targeting a ~700bp variable region of the 18S rRNA gene revealed Sarcocystis hjorti in 73%, S. venatoria/S. iberica in 54%, S. linearis/S. taeniata in 12%, S. pilosa in 8% and S. ovalis in 4% of the deer samples. No inflammatory changes were observed in red deer carcasses with normal appearance (n = 8); however, sarcocysts were observed in one sample, and S. hjorti, S. venatoria/S. iberica or S. silva DNA was detected in five samples. Sarcocystis oocysts/sporocysts were observed in 11/106 faecal and 6/20 intestinal fox samples, and in 2/12 canine samples. Sarcocystis tenella (n = 8), S. hjorti (n = 2), S. gracilis (n = 2), and S. miescheriana (n = 1) were identified in foxes, and S. gracilis (n = 2), S. capreolicanis (n = 1) and S. linearis/S. taeniata (n = 1) in dogs. This study provides first molecular evidence of S. pilosa and S. silva infection in red deer and S. linearis/S. taeniata in dogs and represents the first record of S. ovalis transmitted by corvids in Central Europe. Although Sarcocystis species infecting red deer are not regarded as zoonotic, the affected carcasses can be declared as unfit for human consumption due to the extensive pathological changes.

First molecular characterization of Sarcocystis miescheriana in wild boars (Sus scrofa) from Latvia

Various muscle samples of wild boar (Sus scrofa) from Latvia were studied for the presence of Sarcocystis infection by means of morphological and molecular methods. Sarcocysts were detected in 122 out of 140 (87.1%) wild boar examined. According to the morphological appearance of sarcocysts, the observed cysts belonged to one morphological type and resembled Sarcocystis miescheriana. Twenty-three sarcocysts isolated from the muscles of Latvian wild boars were molecularly characterized at 18S rRNA, ITS1 and cox1. Additionally, eight sarcocysts obtained from Lithuanian wild boars were subjected to molecular analysis in order to compare intraspecific genetic variability. The amplified 18S rRNA region using newly designed primers is sufficiently variable to separate S. miecheriana from S. suihominis. All Latvian and Lithuanian isolates were confirmed belonging to S. miescheriana. No genetic variation was detected within 18S rRNA and ITS1. By contrast, the high intraspecific genetic variability of S. miescheriana was observed within cox1 since each newly obtained sequence represented a unique haplotype. The comparison made using S. miescheriana isolates from Italian and Japanese wild boar and Chinese domestic pig revealed the genetic similarity of the samples depending on their geographical distances. The current study provides the first detection of Sarcocystis infection in wild boars from Latvia and molecular characterization of S. miescheriana.

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

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

Identification of Sarcocystis Spp. in One-humped Camels (Camelus dromedarius) from Riyadh and Dammam, Saudi Arabia, via Histological and Phylogenetic Approaches

Simple Summary

In the present work, we explored the existence of Sarcocystis spp. in samples of camels obtained from abattoirs in Riyadh, Saudi Arabia. We examined tissues of the tongue, heart, esophagus, diaphragm, and skeletal muscle by macroscopic assessments, optical microscopy of tissues, optical microscopy of digested sediment, Transmission Electron Microscopy (TEM), and Polymerase chain reaction (PCR) followed by gene sequencing. The results identified Sarcocystis cameli (S. cameli) and S. camelicanis. Sarcocystis spp. were detected in Saudi Arabian camels by molecular analysis. S. levinei and S. miescheriana were most closely related.

Abstract

Sarcocystis (S.) spp. are intracellular protozoan parasites that infect birds and animals, resulting in substantial commercial losses. Sarcocystis spp. have an indirect life cycle; canines and felines are known to act as final hosts, and numerous domestic and wild animals act as intermediate hosts. The presence of sarcocysts in camel meat may diminish its commercial quality. There is limited knowledge regarding the taxonomy and diagnosis of Sarcocystis spp. that infect camels in Saudi Arabia. In this study, transmission electron microscopy (TEM) revealed S. cameli and S. camelicanis (camelicanis) in Camelus (C.) dromedarius. This is the first report of S. camelicanis in Saudi Arabia and is considered a significant finding. Based on cytochrome c oxidase subunit I gene (COX1) sequences, two samples of Sarcocystis spp. isolated from C. dromedarius in Riyadh and Dammam were grouped with S. levinei hosted by Bubalus bubalis in India, S. rangi hosted by Rangifer tarandus in Norway, S. miescheriana hosted by Sus scrofa in Italy and S. fayeri hosted by Equus caballus in Canada. The sequences obtained in this study have been deposited in GenBank.

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

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