Unraveling Sarcocystis miescheriana and Sarcocystis suihominis infections in wild boar

Molecular Evidence of Raccoon Dog (Nyctereutes procyonoides) as a Natural Definitive Host for Several Sarcocystis Species

Sarcocystis parasites infect a wide range of animals, including reptiles, birds, and mammals, and have complex two-host prey-predator life cycle. Sarcocysts are mainly found in the muscles of intermediate hosts, and oocysts sporulate in the intestines of the definitive host. The raccoon dog (Nyctereutes procyonoides), native to Asia and invasive in Europe, is a known disease carrier. However, studies on raccoon dogs in the transmission of Sarcocystis are scarce. Between 2019 and 2024, a total of 26 raccoon dog carcasses were collected in Lithuania. The results of a light microscopy examination indicated that 50% of the samples were positive for Sarcocystis spp. sporocysts and sporulated oocysts. Based on nested PCR and sequencing of cox1, 88.5% of the samples were positive for these parasites. Molecular analysis revealed the presence of 11 different Sarcocystis species. Eight species, including S. alces, S. capracanis, S. hjorti, S. iberica, S. linearis, S. morae, S. tenella, and S. venatoria were reported for the first time in raccoon dogs as definitive hosts. The identified Sarcocystis species were linked to intermediate hosts, such as cervids, wild boars, pigs, goats, and sheep. These findings suggest that raccoon dogs play a key role in the spread of Sarcocystis, particularly species infecting cervids.

First molecular characterisation of Sarcocystis miescheriana in a pig carcass condemned during routine meat inspection in Poland

Introduction

This article presents the fourth detection of macroscopic cystic lesions due to sarcocystosis in domestic pigs during routine meat inspection worldwide, and the first molecular detection of Sarcocystis miescheriana in a domestic pig in Poland. Pigs can become intermediate hosts for S. miescheriana by accidental ingestion of oocysts or sporocysts present in food or water contaminated by the faeces of canids (definitive hosts).

Material and Methods

The affected swine showed no clinical symptoms such as weight loss, dermatitis or dyspnoea suggesting sarcocystosis. The presence of grossly visible cyst-like lesions was noticed by veterinary inspectors during post-mortem meat inspection of pig carcasses at a slaughterhouse located in central Poland. Ten rice-grain-shaped white lesions were isolated from the muscle tissue for molecular analysis, and four other macroscopic cyst-like lesions were also isolated for histopathological and microscopy analysis. The molecular characterisation included amplification and sequencing of the cytochrome C oxidase subunit 1 mitochondrial gene.

Results

The cyst-like structures were whitish, calcified, 1 cm long and 3 mm wide. The presence of S. miescheriana DNA was confirmed in all ten grossly visible cyst-like lesions.

Conclusion

This study shows that Sarcocystis spp. may be present in swine muscle tissue and cause lesions leading to carcass discard. Further analyses are needed to fully recognise the prevalence and impact of Sarcocystis spp. on animal and human health, especially taking into account the possible presence of the zoonotic S. suihominis.

Gross lesions associated with Sarcocystis miescheriana in a wild boar hunted for human consumption: the importance of trained hunters to ensure animal health surveillance and food safety

Sarcocystis is a genus of protozoa with a worldwide distribution infecting a wide range of animals, including humans. Wild boars can harbor at least two species of Sarcocystis, that is, the zoonotic Sarcocystis suihominis, using humans as definitive hosts, and Sarcocystis miescheriana, for which wild and domestic canids serve as definitive hosts. In Portugal, hunting holds significant economic and social importance, and wild boars are among the most appreciated hunted species. As the consumption of wild boar meat can expose humans to several foodborne pathogens, the presence of trained hunters can make a difference in ensuring animal health surveillance and food safety. Herein, we report the detection of macroscopic cystic lesions associated with S. miescheriana in a wild boar hunted for human consumption, resulting in carcass condemnation. To the best of the authors' knowledge, the presence of S. miescheriana in wild boar tissues has never been associated with macroscopic pathological alterations before. Although S. miescheriana cannot infect humans, carcasses affected by grossly visible pathological changes must be declared unfit for consumption. Therefore, our finding points out the potential economic damage associated with carcass rejection due to the presence of gross lesions associated with generalized sarcocystosis. Nonetheless, further studies are required to investigate these alterations that currently appear to be occasional findings.

Microscopic detection and molecular characterization of Sarcocystis miescheriana in wild boars (Sus scrofa): first report from Greece

The genus Sarcocystis includes protozoan parasites with an indirect life cycle. Sarcocystis spp. can infect various animal species and humans, causing sarcocystosis, a parasitosis of economic importance and zoonotic concern. Wild boars can act as intermediate hosts for Sarcocystis miescheriana and the zoonotic Sarcocystis suihominis that infects humans by consumption of raw or undercooked infected swine meat. In the present study, the diaphragmatic muscle tissue of 123 wild boars hunted in Greece was examined to determine the frequency of Sarcocystis spp. The samples were examined by tissue compression and molecular techniques. Under light microscopy, 34 out of 123 (27.6%) wild boars tested positive for Sarcocystis spp., while a higher infection prevalence (75%) was revealed by multiplex PCR performed in 100 of the samples. The partial mtDNA cox1 gene (~ 1100 bp) of 20 samples tested positive for S. miescheriana by multiplex PCR was amplified and sequenced. Sarcocystis miescheriana was identified as the only species involved in these infections. This is the first study on the prevalence of Sarcocystis spp. in wild animals in Greece. Further, large-scale surveys are needed to assess the prevalence and species of this parasite in Greece and to design efficient control and preventive measures in a One Health perspective.

Red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) as potential spreaders of Sarcocystis species

Background

Sarcocystis includes a global group of apicomplexan parasites with two-host life cycle frequently circulating in wildlife and domestic hosts, including humans. Two of the most important wild terrestrial carnivores acting as definitive hosts are the red fox and raccoon dog, due to their wide distribution in Europe and usage of wild and farmed animals as prey. This study was conducted to determine the prevalence of Sarcocystis in hunted red foxes and raccoon dogs from nine regions of the Czech Republic and to identify isolated sporocysts by molecular techniques.

Methods

Approximately 5 g of the contents of large intestine from 200 animals (197 red foxes and three raccoon dogs) were examined by flotation centrifugation coprological method. Only samples of 50 red foxes and one raccoon dog positive to Sarcocystis spp. were used for the nested PCR (nPCR) method to amplify a fragment or partial sequence on the cox1 gene. Ten species-specific primer pairs for detection of Sarcocystis spp. using farm animals as intermediate hosts were utilized.

Results

In total, 38.1% of the red foxes and 66.7% of the raccoon dogs were positive to Sarcocystis by light microscopy. The molecular characterization resulted in the identification of five species in the red fox: S. arieticanis, S. capracanis, S. cruzi, S. miescheriana, and S. tenella, while the PCR was negative for the sole raccoon dog. The highest intraspecific variation was found for S. miescheriana, while S. tenella was the most prevalent. Co-infections occurred in the large intestine of the red fox. No zoonotic species were found in our samples.

Conclusion

This is the first study where the potential role of the red fox and raccoon dogs as spreaders of Sarcocystis to farm animals in the Czech Republic is shown. The use of species-specific primers provides a fast and easy method for screening multiple samples for a particular Sarcocystis species.

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.

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 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.

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.

Endoparasites of Wild Boars (Sus Scrofa) in Primorsky Krai, Russia

This study identified helminthic species among wild boars (Sus scrofa) in Primorsky Krai, Russia. In total, 66 fecal samples were taken from wild boars and examined using the floatation-sedimentation method to identify helminths eggs and protozoan cysts. Age and sex were estimated for each host animal investigated. The helminthic fauna of the wild boars examined involved six parasite genera, but 4 are helminths and 2 are protozoans: the nematodes Metastrongylus spp., Trichuris suis, Capillaria sp. and Ascaris suum; and the protozoan parasites Eimeria sp. and Cystoisospora suis.

The most prevalent parasite was Metastrongylus spp. (13.6 %) followed by Trichuris suis (7.6 %).

The other parasites found were Eimeria sp. (3 %), Ascaris suum (3 %), Capillaria sp. (1.5 %) and Cystoisospora suis (1.5 %).

Not found positive correlation between the host’s age and sex and the parasite prevalence. This was the first detailed study on helminths infections among wild boars in Primorsky Krai.

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.

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.

Investigation of Mycobacterium bovis and Metastrongylus sp. co-infection and its relationship to tuberculosis lesions' occurrence in wild boars

Animal tuberculosis (aTB) is a zoonotic disease characterized by granulomatous lesions on affected tissues, occurring as a consequence of immunological response to infection. Mycobacterium bovis, the main causative agent of aTB, was investigated in Brazilian wild boars with 37.7 % (29/77) positivity. Among these animals, most had no macroscopic tuberculosis-like lesions (89.6 %; 26/29). The existence of co-infections, which may alter an individual's immune response to an immunological challenge, could influence the formation of tuberculosis lesions. Therefore, we investigated Metastrongylus sp. and aTB co-infection to seek an explanation for the absence of macroscopic lesions in aTB. Of the tested animals, 77.9 % (60/77) had Metastrongylus sp., however, there was no association between its occurrence and the pattern of aTB lesions. The absence of tuberculous lesions in infected animals is worrisome, especially to hunters who handle their carcasses, potentially assuming that the animal is healthy. Studies evaluating other possibilities that can explain the absence of lesions in infected animals should be carried out to better understand these findings.

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.

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.

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

A sample of the diaphragm was collected from each of 100 wild boars legally hunted in the Val Grande National Park in north-western Italy and examined for the presence of Sarcocystis infection by histological and molecular methods. In histological sections, thick-walled sarcocysts consistent with those of Sarcocystis miescheriana were detected in 32 wild boars. Genomic DNA extracted from diaphragm samples was initially subjected to PCR amplification of the internal transcribed spacer 1 (ITS1) region, and 97 wild boars were found to harbour a Sarcocystis infection at this screening. Selected DNA samples were then subjected to PCR amplification and sequencing of the ITS1 region and the 18S and 28S ribosomal RNA (rRNA) genes of the nuclear ribosomal DNA unit, while all positive samples were subjected to PCR amplification of the mitochondrial cytochrome c oxidase subunit I (cox1) gene. S. miescheriana was identified in 97 wild boars (97%), while the zoonotic Sarcocystis suihominis was identified in one wild boar (1%), which also harboured S. miescheriana. Intra-specific sequence variation was found in all four DNA regions of S. miescheriana examined and in the 18S rRNA gene and ITS1 region of S. suihominis. The partial cox1 gene was amplified and sequenced from 72 isolates of S. miescheriana, yielding 43 haplotypes with pairwise sequence identities of 97.6-99.9%. These haplotypes were 79.1-79.8% identical with the cox1 sequence of S. suihominis. Phylogeny based on cox1 sequences placed S. miescheriana and S. suihominis as sister species within a clade comprising mainly Sarcocystis spp. of ruminants with felids as known or presumed definitive hosts. The same was true for the phylogeny based on 18S rRNA gene sequences.

Recolonizing gray wolves increase parasite infection risk in their prey

The recent recolonization of Central Europe by the European gray wolf (Canis lupus) provides an opportunity to study the dynamics of parasite transmission for cases when a definitive host returns after a phase of local extinction. We investigated whether a newly established wolf population increased the prevalence of those parasites in ungulate intermediate hosts representing wolf prey, whether some parasite species are particularly well adapted to wolves, and the potential basis for such adaptations. We recorded Sarcocystis species richness in wolves and Sarcocystis prevalence in ungulates harvested in study sites with and without permanent wolf presence in Germany using microscopy and DNA metabarcoding. Sarcocystis prevalence in red deer (Cervus elaphus) was significantly higher in wolf areas (79.7%) than in control areas (26.3%) but not in roe deer (Capreolus capreolus) (97.2% vs. 90.4%) or wild boar (Sus scrofa) (82.8% vs. 64.9%). Of 11 Sarcocystis species, Sarcocystis taeniata and Sarcocystis grueneri occurred more often in wolves than expected from the Sarcocystis infection patterns of ungulate prey. Both Sarcocystis species showed a higher increase in prevalence in ungulates in wolf areas than other Sarcocystis species, suggesting that they are particularly well adapted to wolves, and are examples of "wolf specialists". Sarcocystis species richness in wolves was significantly higher in pups than in adults. "Wolf specialists" persisted during wolf maturation. The results of this study demonstrate that (1) predator-prey interactions influence parasite prevalence, if both predator and prey are part of the parasite life cycle, (2) mesopredators do not necessarily replace the apex predator in parasite transmission dynamics for particular parasites of which the apex predator is the definitive host, even if meso- and apex predators were from the same taxonomic family (here: Canidae, e.g., red foxes Vulpes vulpes), and (3) age-dependent immune maturation contributes to the control of protozoan infection in wolves.

Occurrence and first molecular characterization of Sarcocystis spp. in wild boars (Sus scrofa) and domestic pigs (Sus scrofa domesticus) in Romania: Public health significance of the isolates

Domestic and wild pigs, as intermediate hosts, can harbor tissue cysts of three Sarcocystis species namely S. miescheriana, S. suihominis and S. porcifelis. Out of them, S. suihominis is zoonotic. Romania is a country with high consumption of raw and/or undercooked traditional pork products. This fact may greatly favor the acquiring of the zoonotic Sarcocystis infections by humans, as definitive host. Based on this consideration and in order to investigate the occurrence and public health significance of Sarcocystis spp. in two western counties (Caraş-Severin and Timiş) of Romania, a total of 165 heart samples from hunted wild boars (Sus scrofa, n=101) and home slaughtered domestic pigs (Sus scrofa domesticus, n=64) were screened using microscopic fresh examination and molecular methods. Microscopic examination revealed the presence of sarcocysts in 60.4% of wild boars, and 23.4% of domestic pigs. Genetic characterization of isolates through the PCR-RFLP procedure, targeting the 18S rRNA gene, was successfully achieved for all microscopically positive samples, indicating the presence of a single species, S. miescheriana, in both hosts. The identity of 13 selected S. miescheriana isolates was also confirmed through sequencing. The tested hosts older than 27 months were found to be significantly higher infected (p<0.05) with Sarcocystis than the 6 to ≤27months age group. Although the human infective S. suihominis has not been registered, for a more reliable epidemiological picture, further molecular studies enrolling a larger number of animals and diagnosis on human intestinal Sarcocystis infections are still necessary.

Population expansion and individual age affect endoparasite richness and diversity in a recolonising large carnivore population

The recent recolonisation of the Central European lowland (CEL) by the grey wolf (Canis lupus) provides an excellent opportunity to study the effect of founder events on endoparasite diversity. Which role do prey and predator populations play in the re-establishment of endoparasite life cycles? Which intrinsic and extrinsic factors control individual endoparasite diversity in an expanding host population? In 53 individually known CEL wolves sampled in Germany, we revealed a community of four cestode, eight nematode, one trematode and 12 potential Sarcocystis species through molecular genetic techniques. Infections with zoonotic Echinococcus multilocularis, Trichinella britovi and T. spiralis occurred as single cases. Per capita endoparasite species richness and diversity significantly increased with population size and changed with age, whereas sex, microsatellite heterozygosity, and geographic origin had no effect. Tapeworm abundance (Taenia spp.) was significantly higher in immigrants than natives. Metacestode prevalence was slightly higher in ungulates from wolf territories than from control areas elsewhere. Even though alternative canid definitive hosts might also play a role within the investigated parasite life cycles, our findings indicate that (1) immigrated wolves increase parasite diversity in German packs, and (2) prevalence of wolf-associated parasites had declined during wolf absence and has now risen during recolonisation.

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

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