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

Sarcocystis spp. Macrocysts Infection in Wildfowl Species in Eastern Baltic Region: Trends in Prevalence in 2011-2022

Wildfowl meat infected with S. rileyi macrocysts is not suitable for human consumption. Ducks are among the main game birds in Europe, and S. rileyi infections cause significant economic losses. In 2011-2022, a total of 2649 anseriforms collected in Lithuania and 619 Mallards (Anas platyrhynchos) hunted in the Kaliningrad region of Russia, Belarus, and Latvia were tested for macrocysts. In Lithuania, macrocysts were detected in 206 of 2362 Mallards (8.7%) and in two of 88 (2.3%) Eurasian Teals (Anas crecca). The prevalence of macrocysts in the other three countries, Belarus (5.9%), Russia (5.0%), and Latvia (3.1%), was similar. For species identification, macrocysts isolated from 37 Mallards (21 from Lithuania, 8 from Russia, 6 from Belarus, and 2 from Latvia) were subjected to sequencing of the ITS1 region. Based on DNA analysis, S. rileyi was confirmed in all tested birds. By comparing the infection rates of macrocysts in Mallards in Lithuania, significant differences were observed in different years (p = 0.036), and a significantly higher prevalence of infection was established in November-December than in September-October (p = 0.028). Given the amount of data per decade on the prevalence of S. rileyi, awareness of infection needs to be increased.

Description of Sarcocystis platyrhynchosi n. sp. (Apicomplexa: Sarcocystidae) from domestic ducks Anas platyrhynchos (Anseriformes: Anatidae) in China

BACKGROUND

Limited data are currently available on protozoan parasites of the genus Sarcocystis that infect their avian hosts within the order Anseriformes (waterfowl). To date, no Sarcocystis species has been recorded in ducks in China.

METHODS

Leg muscles were sampled from 26 domestic ducks (Anas platyrhynchos) in China in 2021. Morphological characteristics of sarcocysts detected in the muscle tissue were described using light microscopy (LM) and transmission electron microscopy (TEM). Genomic DNA was extracted from single sarcocysts obtained from different ducks, and three genetic markers, 18S ribosomal DNA (18S rDNA), 28S ribosomal DNA (28S rDNA) and mitochondrial (mt) cytochrome oxidase subunit 1 (cox1), were amplified and cloned for sequence analyses.

RESULTS

Sarcocysts were observed by LM in only three of the 28 samples (10.7%). These sarcocysts had a thick cyst wall with numerous brush-like villar protrusions (vps) of 3.8-4.3 μm in length (n = 30) on the cyst surface. TEM observation showed that the sarcocysts had lanceolated vps. Each vps narrowed in the stalk and contained a bundle of microtubules that extended into the ground substance. Comparisons of the new sequences with those deposited in GenBank showed that the most similar sequences were those of Sarcocystis halieti in the great cormorant Phalacrocorax carbo and European starling Sturnus vulgaris, and Sarcocystis calchasi in the domestic pigeon (Columba livia) at the 18S rDNA (99.1% identity); Sarcocystis wenzeli from the domestic chicken Gallus gallus at the 28S rDNA (95.9-96.0% identity); and Sarcocystis speeri from the opossum at the mtcox1 (98.2% identity). The new 18S rDNA, 28S rDNA and mitochondrial cox1 sequences shared up to 99.0%, 95.6% and 97.7% identity, respectively, with those of Sarcocystis spp. obtained from Anseriformes avian hosts. Phylogenetic analysis inferred from the sequences of the three genetic markers placed the organism within a group of Sarcocystis spp. obtained from avian or carnivorous intermediate hosts and avian, marsupial or carnivorous definitive hosts. Based on the morphological observation and molecular analyses, the organism found in the Chinese domestic ducks was regarded as a new species and named Sarcocystis platyrhynchosi n. sp.

CONCLUSIONS

Based on morphology and sequence analyses, the microcysts diagnosed in the domestic ducks examined in this study were named as a new species. This is the first record of Sarcocystis spp. from waterfowl in China. Sarcocysts of similar morphology occur frequently in different Anseriformes birds, and the relationships among these species need to be further clarified in future studies using more molecular markers.

Molecular Identification of Sarcocystis rileyi and Sarcocystis sp. (Closely Related to Sarcocystis wenzeli) in Intestines of Mustelids from Lithuania

The genus Sarcocystis is a group of numerous protozoan parasites having a two-host life cycle. Based on laboratory experiments and/or phylogenetic analysis results it was shown that seven Sarcocystis spp. producing sarcocsyts in bird tissues are transmitted via predatory placental mammals. To date the role of small mammals of the family Mustelidae in the distribution of avian Sarcocystis spp. have not been studied. During the current investigation, intestinal mucosa scrapings of 115 mustelids belonging to five species were tested for S. albifronsi, S. anasi, S. rileyi, and S. wenzeli infecting anseriforms and chickens. Microscopically, free sporocysts, sporulating oocysts, and loose oocysts were found in 61 samples (53.0%). Using nested PCR targeting the ITS1 region and sequencing, S. rileyi was confirmed in eight American minks, two European polecats and single European badger. Sarcocystis sp. was identified in one American mink and one European pine marten. Based on the partial ITS1 region this parasite showed that 100% identity to pathogenic Sarcocystis sp. caused a fatal infection in backyard chickens from Brazil. Phylogenetically, the Sarcocystis sp. identified in our study was most closely related to S. wenzeli parasitising domestic fowl (Gallus domesticus).

The Role of Birds of the Family Corvidae in Transmitting Sarcocystis Protozoan Parasites

Simple Summary

Members of the genus Sarcocystis are protozoan parasites that infect mammals, birds, and reptiles. Sarcocystis spp. have an obligatory two-host prey-predator life cycle. Sarcocysts form in the muscles and central nervous system of the intermediate host, while oocysts and sporocysts develop in the small intestine of the definitive host. There is a lack of studies on omnivorous birds of family Corvidae as potential definitive hosts of Sarcocystis spp. Until now, only S. ovalis has been confirmed to be transmitted via corvids. In the current study, 91 small intestine samples from six corvid species from Lithuania were examined for the presence of Sarcocystis spp. that use birds, carnivorous mammals, and cervids as intermediate hosts. Oocysts of Sarcocystis spp. were observed in 43 samples (47.3%) using a light microscope. Based on molecular methods, 11 Sarcocystis spp., (S. columbae, S. cornixi, S. halieti, S. kutkienae, S. lari, S. turdusi, S. wobeseri, S. arctica, S. lutrae, S. ovalis, and S. oviformis) were identified. These results indicate that corvids may transmit some species of Sarcocystis that use birds and mammals as intermediate hosts.

Abstract

Members of the family Corvidae are ecologically flexible omnivorous birds, particularly adaptive to urban habitats, and living in proximity to humans; these birds may serve as definitive hosts (DH) for Sarcocystis spp., but research about this is lacking. In the present study, intestinal samples from 91 corvids collected in Lithuania were molecularly tested by species-specific PCR targeting the ITS1 and cox1 genes and subsequently sequenced for the presence of Sarcocystis spp. Under a light microscope, oocysts of Sarcocystis spp. were observed in 43 samples (47.3%), while molecular methods, detected Sarcocystis spp. in 77 birds (84.6%). Eleven Sarcocystis spp. (S. columbae, S. cornixi, potentially pathogenic S. halieti, S. kutkienae, S. lari, S. turdusi, S. wobeseri, S. arctica, S. lutrae, S. ovalis, and S. oviformis) were identified in the intestinal samples from six corvid species from Lithuania. Infections with multiple Sarcocystis spp. were detected in 79.2% of the infected corvid birds. Three of the identified Sarcocystis spp. use corvids as intermediate hosts (IH); therefore, corvids may serve as IH and DH of the same Sarcocystis species. Based on molecular results and on corvid diet, omnivorous corvids may play an important role in transmitting Sarcocystis spp.

Sarcocystis rileyi (Apicomplexa) in Anas platyrhynchos in Europe with a potential for spread

Four specimens of mallard (Anas platyrhynchos) shot by local hunters (December 2020 to January 2021 along the eastern coastline of the island of Bornholm in the Baltic Sea) were diagnosed with a heavy load of sarcocysts in the musculature. Morphometric and molecular diagnosis based on rDNA (18 S, ITS1, 28 S) of parasites recovered from two of the birds revealed the causative pathogen to be Sarcocystis rileyi. We further present novel sequences for the entire 5.8 S and ITS2 for this species. Elongate cysts (mean length 5.25 (SD 0.6) mm, width 1.37 (SD 0.2) mm) were recorded in all parts of the striated skeletal musculature of the birds. The main part (72%) of the 2585 cysts in one female mallard was located in the outer superficial pectoral musculature, with 11% in the inner pectoral musculature. Minor but significant parts were found in the dorsal, ventral abdominal, neck and head, legs, hand and arm (wing) musculature. No cysts were found in the smooth musculature. Each cyst contained a median of 3.2 mio bradyzoites indicating that more than 8 billion bradyzoites are available for infection of one or more predators/scavengers ingesting the bird. Bradyzoites (median length 13.5 μm (range 12.1–14.5) and median width 2.66 μm (range 2.1–3.3)) were highly resistant to proteinase treatment, which secures the passage through the stomach of the predator to its intestine where wall penetration takes place. One of the birds was ringed (tagged) in Sweden Island Øland in the Baltic Sea two years before being shot. This is documenting immigration of mallards from northern locations. The parasite species was originally described in North America in 1893 and was commonly reported in this region during the 20th century but not in Europe. Recent cases from Norway, Finland, Lithuania, Poland, UK and Hungary suggest that the species may be spreading geographically. Experienced duck hunters with a 40 years record of hunting on the island reported that this type of infection unprecedented. The final host is reported to be canines (fox, raccoon dog), skunk and mustelids, including ermines and American mink. Presence of these hosts in Europe may allow establishment of the life cycle and further colonization of the local duck populations which calls for implementation of a survey program in Europe.

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Heavy loads of the apicomplexan Sarcocystis riley are described from mallards.

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Sarcocysts occurred in all parts of the striated musculature.

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Sarcocysts dominated in the superficial pectoral muscle.

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The number of bradyzoites in one single mallard was estimated to more than 10 billion.

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Sarcocystis rileyi is a new species record for Denmark.

The Role of Mustelids in the Transmission of Sarcocystis spp. Using Cattle as Intermediate Hosts

There is a lack of research on the role of mustelids in the transmission of various Sarcocystis spp. In the present study we tested the hypothesis that widespread mustelids in Lithuania could be involved in the transmission of Sarcocystis spp. using cattle as intermediate hosts. In 2016-2020, intestinal samples of 84 mustelids were examined. Sarcocystis spp. were identified by species-specific PCR targeting the cox1 gene and subsequent sequencing. Under a light microscope, oocysts/sporocysts of Sarcocystis spp. were observed in 40 samples (47.6%), while using molecular methods, they were detected in 75 animals (89.3%). Four Sarcocystis spp. were identified in the intestinal samples of American mink (Neovisonvison), Beech marten (Martes foina), European pine marten (Martes martes), European badger (Meles meles) and European polecat (Mustela putorius). The prevalence of predominant Sarcocystis spp., S. bovifelis (89.3%) and S. cruzi (73.8%) was significantly higher than that of S. hirsuta (3.6%) and S. hominis (1.2%). In an individual sample, most frequently two Sarcocystis spp. were identified (69.0%), then a single species (15.5%) and three species (4.8%). The present study provides strong evidence that mustelids serve as definitive hosts for Sarcocystis spp. using cattle as intermediate hosts.

Sarcocystis cristata sp. nov. (Apicomplexa, Sarcocystidae) in the imported great blue turaco Corythaeola cristata (Aves, Musophagidae)

Background

Species of Sarcocystis are parasitic protozoa in poikilothermic and homeothermic animals. Out of the 26 valid species in birds as intermediate hosts, none has been reported in those of the order Musophagiformes, such as the great blue turaco Corythaeola cristata (Vieillot, 1816), which is a bird endemic to Central and Western Africa. The examination of great blue turacos imported from the Central Africa Republic to Czech Republic allowed the morphological and molecular characterization of a new species of Sarcocystis.

Methods

Four turacos imported from the Central Africa Republic to a private breeder (Czech Republic) underwent parasitological examination for the presence of sarcocysts through wet mounts of breast, heart and leg muscles. Found parasites were molecularly and histologically studied by four loci (18S rRNA, 28S rRNA, ITS1 and cox1) and haematoxylin and eosin staining, respectively.

Results

Three out of four examined birds harboured numerous sarcocysts in the breast and leg muscles. No macroscopic lesions where observed. Sarcocysts were microscopic, elongate and ribbon-shaped with a wall characterised by the presence of finger-shaped villar protrusions and filled with numerous elongate, banana-shaped bradyzoites, 11.87–14.84 × 2.05–2.92 µm in size. The new species was most closely related to Sarcocystisalbifronsi, Sarcocystisanasi, Sarcocystisatraii, Sarcocystischloropusae, Sarcocystisrileyi, Sarcocystiswenzeli and Sarcocystis sp. isolate from chicken in the four loci.

Conclusions

To our knowledge, this is the first species of Sarcocystis found in a musophagiform bird worldwide. Genetically, S. cristata sp. nov. represents a distinct species. Phylogenetic analyses are useful for predicting potential definitive hosts of the new Sarcocystis species.

Morphological and molecular characterization of Sarcocystis wenzeli in chickens (Gallus gallus) in China

BACKGROUND

There has been considerable confusion concerning the number and classification of Sarcocystis spp. in chickens. Scarce nucleotide data of Sarcocystis spp. from chickens are provided in GenBank. The study aimed to investigate the morphological and molecular characteristics of Sarcocystis spp. found in chickens in China.

METHODS

Tissues from 33 chickens were collected in 2019. Sarcocysts were observed using light (LM) and transmission electron microscopy (TEM). Individual sarcocysts from different chickens were selected for DNA extraction, and five loci, 18S rDNA, 28S rDNA, ITS1 region, the mitochondrial cox1 gene and the apicoplastic rpoB gene, were amplified from each sarcocyst, sequenced and analyzed.

RESULTS

Only S. wenzeli was found in 14 of 33 (42.4%) chickens. Under LM, the sarcocysts were microscopic and exhibited palisade-like villar protrusions measuring 1.5-2.8 μm. Ultrastructurally, the sarcocyst wall contained numerous stubby hill-like villar protrusions. The protrusions included scattered microtubules, which extended from the tips of the protrusions into the ground substance. The five loci were successfully sequenced and the sequences deposited in GenBank. At 18S rDNA, ITS1 and cox1, the most similar sequences in GenBank were those of Sarcocystis sp. obtained from the brains of chickens, i.e. 99.9-100%, 98.1-98.5% and 99.3% identity, respectively. The five loci (18S rDNA, 28S rDNA, ITS1, cox1 and rpoB) showed different levels of interspecific sequence similarity with other closely related species of Sarcocystis (e.g. 99.8%, 99.0-99.2%, 89.3-89.7%, 98.5%, and 97.5%, respectively, with S. anasi). Phylogenetic analysis based on four of the loci (18S rDNA, cox1, rpoB and ITS1) revealed that S. wenzeli formed an independent clade with Sarcocystis spp. that utilize geese or ducks as intermediate hosts and canines as the known or presumed definitive host.

CONCLUSIONS

To our knowledge, the sequences of 28S rDNA and rpoB reported here constitute the first records of genetic markers of Sarcocystis spp. in chickens. Based on molecular analysis, S. wenzeli might be responsible for the neurological disease in chickens, and ITS1 and rpoB are more suitable for discriminating it from closely related Sarcocystis spp. Phylogenetic analysis revealed that S. wenzeli presents a close relationship with Sarcocystis spp. in geese or ducks.

Sarcocystis rileyi in UK free-living wildfowl (Anatidae): surveillance, histopathology and first molecular characterisation

BACKGROUND

Reports from UK hunters of 'rice grains' in muscles of shot wildfowl (Anatidae) coincided temporally with the finding of sarcocystosis in a number of ducks found as part of the Wildfowl & Wetlands Trust long-term general surveillance of found dead waterbirds. Sarcocystis rileyi has also been relatively recently confirmed in wildfowl in north-eastern Europe.

METHODS

This study uses four approaches to investigate UK wildfowl sarcocystosis: first, through a hunter questionnaire that captured historical case data; secondly, through an online reporting system; thirdly, DNA sequencing to characterise UK cases; and fourthly, histological myopathy assessment of infected pectoral muscle.

RESULTS

Our questionnaire results suggest Sarcocystis infection is widely distributed throughout the UK and observed in 10 Anatidae species, reported cases increased since the 2010/2011 shooting season, with the online reporting system reflecting this increase. DNA sequencing (18S rRNA gene and internal transcribed spacer-1 region) of UK isolates confirmed S rileyi in the five dabbling duck host species tested and the associated histopathological myopathy is described.

CONCLUSION

This work highlights an emerging issue to European wildfowl species and provides much opportunity for further research, including the impacts of S rileyi and the described myopathy on host health, fitness and survival.

Sarcocystis rileyi emerging in Hungary: is rice breast disease underreported in the region?

Reports of Sarcocystis rileyi-like protozoa ('rice breast disease') from anseriform birds had been rare in Europe until the last two decades, when S. rileyi was identified in northern Europe and the UK. However, despite the economic losses resulting from S. rileyi infection, no recent accounts are available on its presence (which can be suspected) in most parts of central, western, southern and eastern Europe. Between 2014 and 2019, twelve mallards (Anas platyrhynchos) were observed to have rice breast disease in Hungary, and the last one of these 12 cases allowed molecular identification of S. rileyi, as reported here. In addition, S. rileyi was molecularly identified in the faeces of one red fox (Vulpes vulpes). The hunting season for mallards in Hungary lasts from mid-August to January, which in Europe coincides with the wintering migration of anseriform birds towards the south. Based on this, as well as bird ringing data, it is reasonable to suppose that the first S. rileyi-infected mallards arrived in Hungary from the north. on the other hand, red foxes (Vulpes vulpes), which are final hosts of S. rileyi, are ubiquitous in Hungary, and our molecular finding confirms an already established autochthonous life cycle of S. rileyi in the region. Taken together, this is the first evidence for the occurrence of S. rileyi in Hungary and its region.

Molecular identification of Sarcocystis halieti n. sp., Sarcocystis lari and Sarcocystis truncata in the intestine of a white-tailed sea eagle (Haliaeetus albicilla) in Norway

An emaciated white-tailed sea eagle (Haliaeetus albicilla) from Western Norway was found and nursed briefly before it died. The necropsy revealed that the principal cause of death was an inflammation and occlusion of the bile ducts. A secondary finding was the presence in the intestinal mucosa of numerous sporulated Sarcocystis oocysts measuring 21.8-22.8 × 16.0-17.0 μm. The aim of this study was to identify these oocysts to species level using molecular methods. Genomic DNA was extracted from 10 mucosal scrapings containing oocysts and subjected to PCR amplification and sequencing of four DNA regions: the 18S and 28S rRNA genes, the ITS1 region and the cox1 gene. DNA of three previously known Sarcocystis spp. was identified, but only two of these, Sarcocystis halieti n. sp. and Sarcocystis lari, both employing sea birds as intermediate hosts, were considered to have used the sea eagle as a definitive host and to have formed oocysts in its intestine. The third species found, Sarcocystis truncata, employs red deer as intermediate hosts and seems to use felids as definitive hosts based on its phylogenetic position and prevalence. The sea eagle had probably recently ingested portions of one of the latter hosts (red deer or cat/lynx) containing stages (sarcocysts/oocysts) and thus DNA of S. truncata. The species S. halieti and S. lari could only be unambiguously separated from their most closely related congeners on the basis of their ITS1 sequences. This is the first report of Sarcocystis oocysts in sea eagles and the first identification to species level of Sarcocystis oocysts in any type of eagle. The sea eagle also acted as intermediate host of an unidentified Sarcocystis spp. as evidenced by the finding of six thin-walled sarcocysts in a histological section of cardiac muscle.

Surrogate hosts: Hunting dogs and recolonizing grey wolves share their endoparasites

Understanding how closely related wildlife species and their domesticated counterparts exchange or share parasites, or replace each other in parasite life cycles, is of great interest to veterinary and human public health, and wildlife ecology. Grey wolves (Canis lupus) host and spread endoparasites that can either directly infect canid conspecifics or their prey serving as intermediate hosts of indirectly transmitted species. The wolf recolonization of Central Europe represents an opportunity to study parasite transmission dynamics between wildlife and domestic species for cases when a definitive host returns after local extinction – a situation equivalent to a ‘removal experiment’.

Here we investigate whether the re–appearance of wolves has increased parasite pressure on hunting dogs – a group of companion animals of particular interest as they have a similar diet to wolves and flush wolf habitats when hunting. We compared prevalence (P) and species richness (SR) of helminths and the protozoan Sarcocystis to determine whether they were higher in hunting dogs from wolf areas (n_dogs = 49) than a control area (n_dogs = 29) without wolves. Of particular interest were S. grueneri and S. taeniata, known as ‘wolf specialists’.

Five helminth and 11 Sarcocystis species were identified, of which all helminths and eight Sarcocystis species were shared between dogs and wolves. Overall prevalence and species richness of helminths (P:38.5% vs. 24.1%; SR_mean:0.4 vs. 0.3 species) and Sarcocystis (P:63.3% vs. 65.5%, SR_mean:2.1 vs. 1.8 species) did not differ between study sites. However, hunting dogs were significantly more likely to be infected with S. grueneri in wolf areas (P:45.2% vs. 10.5%; p = 0.035). The findings suggest that wolves indirectly increase S. grueneri infection risk for hunting dogs since cervids are intermediate hosts and occasionally fed to dogs. Furthermore, a periodic anthelminthic treatment of hunting dogs may be an effective measure to control helminth infections regardless of wolf presence.

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General parasite burden in hunting dogs is not increased by wolves.

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General Sarcocystis burden in hunting dogs is high due to raw feeding.

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‘Wolf specialist’ parasite S. grueneri more prevalent in hunting dogs from wolf areas.

Molecular characterization of Sarcocystis spp. in intestine mucosal scrapings and fecal samples of Pampas fox (Lycalopex gymnocercus)

Sarcocystis spp. are obligatory intracellular protozoan parasites which can infect humans and animals. Most of Sarcocystis species were identified based on the detection of muscle cysts in different intermediate hosts (IH). Regarding to natural infection in definitive host, there are few reports which have reached to determining species of Sarcocystis. The present work was aimed to studying the occurrence of Sarcocystis spp. (oocysts and sporocysts) in mucosal scrapings of small intestine and fecal samples of one the most abundant wild canids from South America, Lycalopex gymnocercus (Pampas fox), and to identify the Sarcocystis spp. using molecular tools. A total of 131 free-living L. gymnocercus were sampled in rural areas located in several departments from Buenos Aires province, Argentina. Fecal samples from all the animals and 33 small intestines were analyzed. Fecal and mucosal scrapings samples were analyzed by sugar flotation method and once oocysts or sporocysts were detected, sedimentation was performed and DNA extracted with a commercial kit. A PCR was conducted using primers targeting a fragment of the 18S rRNA gene and the amplicons were purified and sequenced. Of the total Pampas foxes analyzed, 23 (17.6%) had Sarcocystis spp. oocysts/sporocysts in fecal and/or mucosal samples. Sarcocystis spp. sporocysts were detected in 13.0% (17/131) of fecal samples and in 39.4% (13/33) of mucosal samples by the initial sugar flotation. Twenty one L. gymnocercus samples were processed by DNA extraction and PCR. Molecular identification of Sarcocystis spp. infection was successfully achieved in 14 foxes and was distributed as follows: 4.6% S. cruzi (6/131), 3.8% Sarcocystis spp. using birds as IH (S. albifronsi and S. anasi among others, 5/131), 0.8% S. tenella (1/131) and 1.5% (2/131) with low homology (97%) with S. miescheriana. In one fecal sample with spherical oocysts, the sequencing results showed a 100% sequence identity with Hammondia heydorni. The results show that the mucosal scrapings are the eligible sample to identify prevalence and to proceed with species identification. Lycalopex gymnocercus is suggested as definitive host for S. cruzi, S. tenella and probably various Sarcocystis spp. using birds as intermediate hosts as well as for H. heydorni.

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.

Acute fatal sarcocystosis hepatitis in an Indo-Pacific bottlenose dolphin (Tursiops aduncus) in Hong Kong

Unlike most species in the genus Sarcocystis, Sarcocystis canis has a broad intermediate host range. Its life cycle is incompletely known and most reports are from the USA. Here we report fatal hepatitis in a 4year old male Indo-Pacific bottlenose dolphin (Tursiops aduncus) from Hong Kong associated with a S. canis-like infection. Diagnosis was made based on clinical presentation, histopathology, transmission electron microscopy (TEM), and molecular characterization. Microscopically, S. canis-like like infection was confined to the liver. Immature and mature schizonts were found in hepatocytes and the parasite was associated with generalized hepatic necrosis. By TEM, schizonts divided by endopolygeny, and merozoites lacked rhoptries. Molecular characterization of parasites present in liver and brain tissues at the cox1 gene showed a high degree of identity (97-98%) and clustered together with Sarcocystis canis, S. lutrae, S. arctica, S. speeri, S. turdusi, and S. rileyi in a phylogenetic study. This is the first report of S. canis-like infection from Asia.

Molecular identification of Sarcocystis spp. in foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) from Germany

More than 200 Sarcocystis spp. have been named and most of them appear to be involved in a particular predator-prey cycle. Among canids, the European fox (Vulpes vulpes) and the raccoon dog (Nyctereutes procyonoides) are widely distributed in Europe and probably play an important role as definitive hosts in the epidemiology of Sarcocystis spp. infections. A total of 50 small intestines from foxes and 38 from raccoon dogs were sampled in the Federal State of Brandenburg, Germany. Mucosal scrapings were collected and analyzed by sugar flotation and when oocysts or sporocysts were detected, an overnight sedimentation was performed and DNA extracted with a commercial kit. A PCR was conducted using primers targeting a fragment of the 18S rRNA gene (with a size of approximately 850 bp) and the amplicons were purified and sequenced. Samples with an inconclusive sequencing were cloned into plasmids and ≥ 3 plasmids from each amplicon were sequenced. Sarcocystis spp. oocysts/sporocysts were detected in 38% (19/50) of fox and 52.6% (20/38) of raccoon dog samples. Sequencing analysis of amplicons from oocyst DNA revealed mixed infections in 9 fox and 5 raccoon dog samples. In the fox samples, the most often identified Sarcocystis spp. were S. tenella or S. capracanis (10.0%); S. miescheriana (8.0%) and S. gracilis (8.0%) followed by Sarcocystis spp., which use birds as intermediate hosts (6.0%), and S. capreolicanis (4.0%). In the raccoon dog samples, sequences with a ≥99% identity with the following species were detected: S. miescheriana (18.4%), S. gracilis (13.1%), Sarcocystis spp. using birds as IH (10.5%), S. tenella or S.capracanis (2.6%) and S. capreolicanis (2.6%). The estimated prevalence of Sarcocystis spp. infections determined using mucosal scrapings was higher than in related studies performed by analyzing faecal samples. The methodology of 18S rRNA gene amplification, cloning and sequencing is suitable to identify mixed infections with Sarcocystis spp. and to gather information on potential definitive hosts of these parasite species.