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1.
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Fresh preparations of microisolated sarcocysts from striated muscle of several domestic reindeer from northern Norway were examined by light microscopy. In cardiac muscle, cysts of S. grueneri were found. In skeletal muscle, cysts of S. rangiferi, S. tarandi and S. tarandivulpes were found in all samples examined. In the abdominal muscles of some reindeer, one or two other types of cysts were found.Cysts of one type were macroscopic in size, and ovoid to cylindrical in shape. The cysts were surrounded by a 8–12 µm thick layer of fibrous material, and measured 1682×910 µm. The cysts had relatively few and irregularly distributed, 20–35 µm long, and 3–5 µm wide, linguiform cyst wall protrusions, which could only be seen after removal of the fibrous layer. These cysts were classified as cysts of S. hardangeri, a species previously described from wild reindeer in southern Norway.Cysts of the other type were long and slender, measuring 5460–12700 (8994 ± 2575) × 95–280 (180 ± 50) µm. The cysts had numerous very fine, flexible, hair-like cyst wall protrusions, which were 8–10 [xm long and less than 0.5 µm thick. These cysts are considered to belong to a new Sarcocystis species of reindeer, for which the name Sarcocystis rangi n, sp. is proposed. The reindeer is recorded as the intermediate host for 6 different species of Sarcocystis.  相似文献   

3.
Fresh preparations of micro-isolated sarcosysts from skeletal muscle of 5 wild reindeer were examined by light microscopy. Slender, spindelshaped cysts measuring 821 × 60 µm, and having short knob-like cyst wall protrusions were found in all animals. In 1 animal cysts different in structure from the cysts of the 4 previously known Sarcocystis spp. of reindeer were found, These cysts are considered to be cysts of a new Sarcocystis sp. of reindeer, for which the name Sarcocystis hardangeri has been proposed.S. hardangeri n. sp. had macroscopic, ovoid to cylindrical cysts measuring 1667 (900–2570) × 819 (450–1575) µm. The cysts were surrounded by a 8–10 µm thick layer of fibrillar material. After removal of this layer, relatively few and irregularly spaced, slanting protrusions became visible. The 20–30 µm long protrusions were tongue-like, and were lying close to the surface of the cyst.Cysts of S. grueneri, S. rangiferi and S. tarandi were not demonstrated in the 5 wild reindeer examined.  相似文献   

4.
Fresh preparations of micro-isolated sarcocysts from skeletal and cardiac muscle of 12 reindeer were examined by light microscopy. On the basis of cyst structure and cyst wall structure 4 Sarcocystis spp. could be differentiated. New names have been proposed for 2 previously unnamed Sarcocystis spp. of reindeer, and S. grueneri has been redefined.S. rangiferi n. sp. had macroscopic cysts in skeletal muscle measuring 2106×403 µm. The cyst wall protrusions were finger-like and measured 13.2×6.7 µm. The cysts were surrounded by a layer of fibrillar material.S. tarandi n. sp. had micro- to macroscopic cysts primarily in skeletal muscle, but a few cysts were found in the heart of one animal. In skeletal muscle the cysts measured 999×75µm; in the heart the cysts were shorter and wider. The cyst wall protrusions were fingerlike and measured 9.2×2.2 µm.S. grueneri had micro- to macroscopic cysts in cardiac muscle measuring 581×137 µm. The cyst wall was thin and relatively smooth with no visible protrusions.Sarcocystis sp. had micro- to macroscopic, slender cysts in skeletal muscle measuring 916×64 µm. The cyst wall had tightly packed, short, knob-like protrusions. The cysts of this species were previously classified as cysts of S. grueneri.  相似文献   

5.
Six Sarcocystis species have previously been described from reindeer in Norway based on sarcocyst morphology and DNA sequencing. The aim of this study was to determine whether reindeer in Iceland, which descend from reindeer imported from Norway in 1787, also were infected with Sarcocystis, and to identify and genetically characterise any species present. Muscle tissue from the heart, diaphragm and/or oesophagus was collected from 36 reindeer in Iceland. Pieces of all tissue samples were examined histologically. Frozen/thawed samples of cardiac muscle, oesophagus and/or diaphragm from 11 of the 36 reindeer were also examined under a stereoscopic microscope and sarcocysts present were identified to species either in situ or under a light microscope. Two cysts of each species, originating from two different reindeer were randomly selected for DNA analyses. The complete ssu rRNA gene was amplified by the polymerase chain reaction (PCR) and sequenced. In addition, two sarcocysts that could not be classified by microscopic examination were selected for partial ssu rRNA gene sequence analysis. By histology, sarcocysts were found in the diaphragm and/or oesophagus of 8 of 36 (22.2%) animals. By examination of fresh tissue, sarcocysts of Sarcocystis rangi, S. tarandivulpes and S. hardangeri were found in the oesophagus of seven of nine (77.8%) animals, suggesting a high prevalence of Sarcocystis in the Icelandic reindeer population. Cyst morphology and the ssu rRNA gene sequence of each of the three species were identical to isolates of the same species from Norwegian reindeer. DNA sequencing was useful in order to identify cysts with an ambiguous morphology. This is the first record of these Sarcocystis species in reindeer outside Norway.  相似文献   

6.
A raccoon dog (Nyctereutes procyonoides; Family: Canidae), was given cardiac muscle of reindeer infected with S. grueneri, and started shedding Sarcocystis sporocysts 10 days post feeding. The sporocysts measured 13.9 (12.4–15.7) × 10.1 (9.2–11.2) µm, and were excreted for at least 16 days. The raccoon dog is thus an additional definitive host for S. grueneri (Yakimoff & Sokoloff, 1934) Gjerde, 1984.Another raccoon dog was given skeletal muscle infected with 4 species of Sarcocystis, none of which was S. grueneri. The raccoon dog started shedding Sarcocystis sporocysts on day 10 post feeding, and excreted sporocysts for at least 16 days. The sporocysts measured 14.0 (12.3–15.6) × 10.1 (9.2–11.2) µm, and are considered to be sporocysts of S. tarandivulpes Gjerde, 1984.This is the first record of the raccoon dog as an experimental definitive host for Sarcocystis.  相似文献   

7.
The prevalence and identity of Sarcocystis spp. sarcocysts in the skeletal muscles of nine-banded armadillos (Dasypus novemcinctus) collected from Alachua County, FL, were determined. H & E stained sections of skeletal muscle from tongue and thigh were examined. Thirty nine of 63 (61.9%) armadillos examined contained Sarcocystis sarcocysts. Two species were identified, Sarcocystis dasypi and Sarcocystis diminuta. Sarcocystis dasypi sarcocysts were found in 38 of 63 (60.3%) and S. diminuta sarcocysts were found in 6 of 63 (9.5%). Sarcocysts of S. dasypi were larger, more densely packed with bradyzoites, and bradyzoites contained within the sarcocyst were smaller than those of S. diminuta. Mixed infections occurred in 5 of 63 (7.9%) armadillos examined.  相似文献   

8.
Six Sarcocystis species from reindeer (S. grueneri, S. rangi, S. tarandivulpes, S. hardangeri, S. rangiferi and S. tarandi) have previously been genetically characterised. The aim of this study was to identify possible definitive hosts for S. hardangeri, S. rangiferi and S. tarandi by including the six species in phylogenetic analyses of the Sarcocystidae, and also to investigate the phylogenetic relationships between the species from reindeer and those from other hosts. The study also aimed at revealing whether the inclusion of six Sarcocystis species from the same intermediate host would have any effect on previously inferred phylogenetic relationships within the Sarcocystidae. The complete small subunit (ssu) rRNA gene sequences of all six Sarcocystis species from reindeer were used in the phylogenetic analyses along with ssu rRNA gene sequences of 85 other members of the Coccidea. Trees were constructed using Bayesian analysis and maximum likelihood estimations. All six Sarcocystis species from reindeer were placed together with other Sarcocystis species using an even-toed ungulate as their intermediate host. The three canine transmitted species, S. grueneri, S. rangi, S. tarandivulpes, formed a sister group to other Sarcocystis species with a canine definitive host. The position of S. hardangeri on the tree suggested that it uses another type of definitive host than the other Sarcocystis species in this clade. Considering the geographical distribution and infection intensity of S. hardangeri, corvid birds are perhaps its most likely definitive hosts. The phylogenetic position, geographical distribution, prevalence and morphological similarity to feline transmitted Sarcocystis species in closely related Cervidae suggest that the most likely definitive hosts of S. rangiferi and S. tarandi are felines, and in Norway notably the lynx. The overall phylogeny of the Sarcocystidae did not change by the inclusion of the six Sarcocystis species from reindeer. This study suggests that phylogentic analysis can be a useful tool in the search for possible definitive hosts for those Sarcocystis species for which they are unknown and difficult to find solely by other methods.  相似文献   

9.
Microscopic sarcocysts recovered from naturally infected sheep were infective to both the domestic dog (Canis familiaris) and the red fox (Vulpes vulpes). The parasite was passaged through experimental specific-parasite-free (SPF) sheep three times: infection was transmitted twice with sporocysts from foxes and subsequently with sporocysts from dogs. The sarcocysts from sheep muscle were infective to both dogs and foxes on each occasion. A cat was not infected. The prepatent period in individual canids ranged from 7 to 15 days. Sporocyst excretion was still detectable 60 days post infection. This study establishes that canids of two genera may act as vectors for a single isolate of the same Sarcocystis species from sheep.  相似文献   

10.
We tested the hypothesis that brown-headed cowbirds (Molothrus ater) harbor Sarcocystis neurona, the agent of equine protozoal myeloencephalitis (EPM), and act as intermediate hosts for this parasite. In summer 1999, wild caught brown-headed cowbirds were collected and necropsied to determine infection rate with Sarcocystis spp. by macroscopic inspection. Seven of 381 (1.8%) birds had grossly visible sarcocysts in leg muscles with none in breast muscles. Histopathology revealed two classes of sarcocysts in leg muscles, thin-walled and thick-walled suggesting two species. Electron microscopy showed that thick-walled cysts had characteristics of S. falcatula and thin-walled cysts had characteristics of S. neurona. Thereafter, several experiments were conducted to confirm that cowbirds had viable S. neurona that could be transmitted to an intermediate host and cause disease. Specific-pathogen-free opossums fed cowbird leg muscle that was enriched for muscle either with or without visible sarcocysts all shed high numbers of sporocysts by 4 weeks after infection, while the control opossum fed cowbird breast muscle was negative. These sporocysts were apparently of two size classes, 11.4+/-0.7 microm by 7.6+/-0.4 microm (n=25) and 12.6+/-0.6 microm by 8.0+/-0 microm (n=25). When these sporocysts were excysted and introduced into equine dermal cell tissue culture, schizogony occurred, most merozoites survived and replicated long term and merozoites sampled from the cultures with long-term growth were indistinguishable from known S. neurona isolates. A cowbird Sarcocystis isolate, Michigan Cowbird 1 (MICB1), derived from thin-walled sarcocysts from cowbirds that was passaged in SPF opossums and tissue culture went on to produce neurological disease in IFNgamma knockout mice indistinguishable from that of the positive control inoculated with S. neurona. This, together with the knowledge that S. falcatula does not cause lesions in IFNgamma knockout mice, showed that cowbird leg muscles had a Sarcocystis that fulfills the first aim of Koch's postulates to produce disease similar to S. neurona. Two molecular assays provided further support that both S. neurona and S. falcatula were present in cowbird leg muscles. In a blinded study, PCR-RFLP of RAPD-derived DNA designed to discriminate between S. neurona and S. falcatula showed that fresh sporocysts from the opossum feeding trial had both Sarcocystis species. Visible, thick-walled sarcocysts from cowbird leg muscle were positive for S. falcatula but not S. neurona; thin-walled sarcocysts typed as S. neurona. In 1999, DNA was extracted from leg muscles of 100 wild caught cowbirds and subjected to a PCR targeting an S. neurona specific sequence of the small subunit ribosomal RNA (SSU rRNA) gene. In control spiking experiments, this assay detected DNA from 10 S. neurona merozoites in 0.5g of muscle. In the 1999 experiment, 23 of 79 (29.1%) individual cowbird leg muscle samples were positive by this S. neurona-specific PCR. Finally, in June of 2000, 265 cowbird leg muscle samples were tested by histopathology for the presence of thick- and thin-walled sarcocysts. Seven percent (18/265) had only thick-walled sarcocysts, 0.8% (2/265) had only thin-walled sarcocysts and 1.9% (5/265) had both. The other half of these leg muscles when tested by PCR-RFLP of RAPD-derived DNA and SSU rRNA PCR showed a good correlation with histopathological results and the two molecular typing methods concurred; 9.8% (26/265) of cowbirds had sarcocysts in muscle, 7.9% (21/265) had S. falcatula sarcocysts, 1.1% (3/265) had S. neurona sarcocysts, and 0.8% (2/265) had both. These results show that some cowbirds have S. neurona as well as S. falcatula in their leg muscles and can act as intermediate hosts for both parasites.  相似文献   

11.
Muscle tissue from the oesophagus, diaphragm and heart of 100 cattle slaughtered in Belgium was examined for Sarcocystis infection by microscopic examination of tissue and artificial digestion. Intact sarcocysts or cystozoietes were recovered from 97% of the cattle examined. There was a difference in sensitivity between the method (digestion or histology) used and the muscle processed. The digestion of the oesophagus muscle resulted in the highest number of positive animals whereas the heart muscles contained most cysts during histological examination. Thin-walled cysts were recovered from all positive animals especially in the heart and they were indistinguishable from those of S. cruzi. Thick-walled cysts were recovered from 56% of animals but these could not be identified as S. hirsuta and/or S. hominis on morphological grounds. A correlation between pathological changes and the infection grade could not be proved.  相似文献   

12.
Tissue samples comprising the oesophagus and diaphragm were collected from 400 sheep and 400 goats slaughtered at the abattoirs in the study area. Out of this number, 36 were positive for Sarcocystis cysts (sarcocysts) in sheep and 56 in goats. The sarcocysts in sheep measured 35.7 to 500 microns lengthwise and the cyst-wall 2.4 microns. They were identified to be Sarcocystis tenella. The cysts in goats measured 98 to 700 microns and the cyst-wall 2.7 microns. They were identified to be Sarcocystis capracanis. In both animals species, the sarcocysts were more frequent in the oesophagus than in the diaphragm. All sarcocysts seen were microscopic.  相似文献   

13.
Sarcocystis neurona is the parasite most commonly associated with equine protozoal myeloencephalitis (EPM). Recently, cats (Felis domesticus) have been demonstrated to be an experimental intermediate host in the life cycle of S. neurona. This study was performed to determine if cats experimentally inoculated with culture-derived S. neurona merozoites develop tissue sarcocysts infectious to opossums (Didelphis virginiana), the definitive host of S. neurona. Four cats were inoculated with S. neurona or S. neurona-like merozoites and all developed antibodies reacting to S. neurona merozoite antigens, but tissue sarcocysts were detected in only two cats. Muscle tissues from the experimentally inoculated cats with and without detectable sarcocysts were fed to laboratory-reared opossums. Sporocysts were detected in gastrointestinal (GI) scrapings of one opossum fed experimentally infected feline tissues. The study results suggest that cats can develop tissue cysts following inoculation with culture-derived Sarcocystis sp. merozoites in which the particular isolate was originally derived from a naturally infected cat with tissue sarcocysts. This is in contrast to cats which did not develop tissue cysts when inoculated with S. neurona merozoites originally derived from a horse with EPM. These results indicate present biological differences between the culture-derived merozoites of two Sarcocystis isolates, Sn-UCD 1 and Sn-Mucat 2.  相似文献   

14.
A rock pigeon (Columba livia) caught in Akihabara, Tokyo, showed neurological symptoms, such as head tilt and circling. Pathological examinations revealed abundant Sarcocystic cysts in the skeletal muscle and myocardium with mild myositis, and numerous schizonts and sarcocysts with severe multifocal granulomatous T-lymphocytic infiltration in the central nervous system. A Sarcocystis calchasi-specific gene was detected in the muscle and brain. This case indicates S. calchasi was distributed in Japan and caused severe encephalitis to rock pigeons.  相似文献   

15.
Sarcocystis infection was diagnosed in 27 of 36 (75%) samples of meat from white-tailed deer (Odocoileus virginianus) in Montana. Two structurally distinct thin- and thick-walled sarcocysts were found in the white-tailed deer; the thin-walled sarcocysts were those of S odocoileocanis. A new name, S odoi, was proposed for the thick-walled sarcocysts. Sarcocysts of S odoi were up to 1,050 microns long and 260 microns wide and contained a 6.5- to 12-microns thick wall. The ultrastructure of sarcocysts of S odocoileocanis was compared with that of S odoi. A cat fed meat containing thin- and thick-walled sarcocysts shed oocysts and sporocysts 24 days later. The sporocysts in the cat's feces were 13.3 X 9.6 microns and probably belonged to S odoi.  相似文献   

16.
From 1974 to 1977, 62 wild mule deer (Odocoileus hemionus) fawns from Steens Mountain, Ore were euthanatized in autumn (23 deer), winter (21 deer), and spring (18 deer). The number of sarcocysts of Sarcocystis spp was counted in histologic sections of various muscular organs. Sarcocysts were seen in the muscle specimens of 14 of the 23 deer euthanatized in autumn (September to November) and in specimens from all 39 deer euthanatized in winter (December and January) and spring (March and April). The sarcocyst burden was greatest in the spring (736/deer), less in the winter (150/deer), and least in autumn (12/deer). Most sarcocysts collected from 3- to 5-month-old deer in autumn were immature, whereas most sarcocysts collected from 9- and 10-month-old deer in the spring were mature. More sarcocysts were seen in sections of muscles from limbs than in those of tongue, esophagus, and other skeletal muscles; the fewest sarcocysts were seen in the heart. Degenerating sarcocysts were seen in deer examined in the spring, but not in deer examined in autumn and winter. Sarcocystis was the only infectious agent found in unthrifty deer fawns. Of the 18 fawns (6 in autumn, 1974; 6 in winter, 1974; and 6 in spring, 1975) examined for helminths, only mild infections were seen in the deer examined in the spring of 1975. From 1974 to 1977, from the Crooked Creek area of Oregon, 48 mule deer fawns (12 in autumn, 18 in winter, and 18 in spring) were euthanatized and evaluated for Sarcocystis infections.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
Macroscopically visible Sarcocystis spp. cysts isolated from the skeletal muscle of slaughtered cattle were examined by light- and electronmicroscopy. Transmission experiments involving cats, dogs and a human volunteer were also carried out. The cysts could only be transmitted to cats which establishes them with a high degree of certainty as Sarcocystis hirsuta. The cyst wall (including protrusions) ranged from 3.3 to 7.0 micron in thickness and the individual cyst wall protrusions from 1.2 to 2.6 micron in width. Transmission and scanning electronmicroscopy revealed previously undescribed features of the cyst wall. It appears that, with increasing age, the cyst wall protrusions become larger and develop a highly irregular surface. Their attachments to the cyst wall are slender and widely spaced indicating that growth of the cyst continues without the formation of new protrusions. Within the protrusions the fibrils become disorganised and numerous osmiophilic granules appear. It is evident that major changes in the structure of sarcocysts can occur with age.  相似文献   

18.
Sarcocystis cruzi, S. hirsuta and S. hominis are apicomplexan parasites that affect cattle worldwide with variable prevalence. The aim of the present study was to evaluate the prevalence of Sarcocystis spp. in Argentinean cattle comparing microscopic fresh examination and molecular methods. Blood, myocardium and loin samples were collected in five slaughterhouses from a total of 380 bovines. Origin of animals was representative of the major beef cattle production area of Argentina. Samples were analyzed by fresh microscopical examination, transmission electron microscopy (TEM), IFAT and PCR-RFLP. Thin walled sarcocysts corresponding with S. cruzi were found in 99.5% of heart samples. Sarcocysts were detected in 73.1% of loin samples; 71.5% had S. cruzi cysts and 23.1% had thick walled sarcocysts (S. hirsuta or S. hominis). TEM observation revealed the presence of characteristic S. hominis and S. hirsuta cyst walls in 7 and 1 loin samples respectively. Using IFAT, 379/380 animals had titers 25 or higher, showing a full agreement with fresh examination. Amplification products were detected in 35.5% (135/380) of loin samples; however Sarcocystis species could only be determined by RFLP in 29 samples. Agreement between fresh examination and PCR was low (Kappa value=0.262). This is the first report of S. hominis and S. hirsuta in Argentina. Further studies are needed to improve the sensitivity of molecular methods for species identification, especially for differentiation of S. cruzi and S. hirsuta from the zoonotic species S. hominis. The results of the present study and others focusing on sensitivity and specificity of Sarcocystis spp. diagnostic methods should contribute to improve food safety.  相似文献   

19.
20.
Tissue stages similar to those of Sarcocystis neurona, the causative agent of equine protozoal myeloencephalitis, were identified in skeletal muscles of a dog. The dog, a 6-year-old Labrador retriever, was seropositive for Toxoplasma gondii infection and euthanized due to a history of polymyositis and progressive muscular atrophy. Histologically, 30, variably sized, microscopic, intracellular sarcocysts were observed in 60 sections of skeletal muscles taken from the neck, fore limbs and hind limbs. The cysts were only observed in inflamed skeletal muscles, but were mostly in myocytes at the periphery of areas infiltrated with leukocytes. Ultrastructurally, the cyst wall had villar protrusions consistent with sarcocysts. Immunohistochemistry with monoclonal S. neurona antibodies demonstrated positive labeling of zoites in merozoites or schizonts in the skeletal muscle interstitium, but no labeling of the sarcocysts. Initial PCR analysis with primers amplifying a genetic sequence encoding Apicomplexan 18s rRNA, and subsequent PCR analysis with differentiating primers indicated that the genetic sequences had 100% identity with sequences reported for S. neurona.  相似文献   

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