Publications

isolation of a third species of sarcocystis in immunodeficient mice fed feces from opossums (didelphis virginiana) and its differentiation from sarcocystis falcatula and sarcocystis neurona.	opossums (didelphis virginiana) were found to be hosts for 3 species of sarcocystis: sarcocystis falcatula with an avian intermediate host, s. neurona with an undetermined intermediate host, and a third, unnamed, species. sporocysts from the intestines of 2 opossums (nos. 26 and 47) were fed to budgerigars (melopsittacus undulatus), nude mice, and gamma-interferon knockout (ko) mice. sporocysts of s. falcatula were not infective to nude or ko mice. sporocysts of s. neurona induced encephalitis i ...	1998	9920306
meningoencephalitis due to a sarcocystis neurona-like protozoan in pacific harbor seals (phoca vitulina richardsi).	seven pacific harbor seals with meningoencephalitis associated with sarcocystis neurona-like protozoa are described. six of the 7 seals were free-ranging and were found stranded over an 80-km stretch of central california coastline; the other was captive. all had marked to severe nonsuppurative meningoencephalitis, most severe in the cerebellar cortex. immunohistochemistry for s. neurona antigens was positive on brain tissue in all cases, revealing numerous merozoites as well as developing and m ...	1998	9920311
isolation in immunodeficient mice of sarcocystis neurona from opossum (didelphis virginiana) faeces, and its differentiation from sarcocystis falcatula.	sarcocystis neurona was isolated in nude mice and gamma-interferon knockout mice fed sporocysts from faeces of naturally infected opossums (didelphis virginiana). mice fed sporocysts became lethargic and developed encephalitis. protozoa were first found in the brain starting 21 days post-inoculation. sarcocystis neurona was recovered in cell culture from the homogenate of liver, spleen and brain of a nude mouse 11 days after feeding sporocysts. the protozoa in mouse brain and in cell culture mul ...	1998	9925260
serum antibodies to sarcocystis neurona--half the horses in the united states have them!		1997	9040830
seroprevalence of antibodies to sarcocystis neurona in horses residing in a county of southeastern pennsylvania.	to determine seroprevalence of sarcocystis neurona-specific antibodies in a population of horses residing in chester county, pa.	1997	9040838
seroprevalence of antibodies to sarcocystis neurona in horses residing in ohio.	to determine the seroprevalence of serum antibodies to sarcocystis neurona in horses residing in ohio.	1997	9040839
seroprevalence of antibodies to sarcocystis neurona in horses residing in oregon.	to determine seroprevalence of antibodies to sarcocystis neurona in neurologically normal horses residing in 4 regions of oregon and to describe the effects of age, gender, breed, and housing on seroprevalence within each region.	1997	9040840
experimental induction of equine protozoal myeloencephalitis in horses using sarcocystis sp. sporocysts from the opossum (didelphis virginiana).	sarcocystis sp. sporocysts isolated from eight feral opossums (didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (melopsittacus undulatus), 14 wild-caught sparrows (passer domesticus), one wild-caught slate-colored junco (junco hyemalis) and five weanling horses (equus caballus). all budgerigars died within 5 weeks post inoculation (wpi). histologic examination revealed meronts within the pulmonary epithelia and typical sarcocystis falcatula sarcocysts developing in ...	1997	9066066
epizootic of equine protozoal myeloencephalitis on a farm.	to determine the clinical findings, course of treatment, and long-term outcome of horses on a farm in central kentucky during an epizootic of equine protozoal myeloencephalitis (epm).	1997	9096721
equine protozoal myeloencephalitis.	equine protozoal myeloencephalitis (epm) is a common neurologic disease of horses in the americas. horses with epm most commonly have abnormalities of gait, but they also may present with signs of brain disease. the disease ranges in severity from mild lameness to sudden recumbency, and clinical signs usually are progressive. a causative agent, sarcocystis neurona, has been isolated from affected horses, and serologic surveys suggest that approximately 50% of horses in the united states have bee ...	1997	9106345
fatal hepatic sarcocystosis in two polar bears (ursus maritimus).	fatal hepatic sarcocystosis was diagnosed in 2 polar bears from a zoo in anchorage, alaska. gross lesions were icterus and systemic petechiae. marked microscopic lesions were detected only in the liver and included severe random necrotizing hepatitis with hemorrhage. only asexual stages of an apicomplexan parasite were detected within hepatocytes, and rare extracellular zoites were seen in foci of necrosis. the parasite divided by endopolygeny, and occasionally merozoites formed rosettes around ...	1997	9194839
micropreparative high resolution purification of proteins by a combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, isoelectric focusing, and membrane blotting.	we report a simple, economical, and efficient protocol for protein purification from cells. first, proteins of cell lysates were separated by standard sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and electroblotted to protein-blotting membrane. the blots were stained with coomassie blue or developed by immunoblotting to visualize specific proteins. the bands corresponding to those visible by immunoblotting were excised from the dye-stained blots and subjected to isoelectr ...	1997	9234899
pyogranulomatous encephalitis associated with an unidentified sarcocystis neurona-like organism in a horse.		1997	9249180
examination of extraintestinal tissue cysts of isospora belli.	relapse is common in immunocompetent and immunosuppressed humans infected with isospora belli and is believed to be associated with the presence of extraintestinal stages. in the present study, we examined this important stage in an aids patient using histological, immunohistological, histochemical, and ultrastructural methods to better understand the development and structure of this stage and to develop better means of detecting infections. antisera made in rabbits to isospora suis, toxoplasma ...	1997	9267401
experimental infection of nude mice as a model for sarcocystis neurona-associated encephalitis.	the development of a rodent model for the study of sarcocystis neurona encephalitis is described. animal models have been developed for a number of protozoal parasites; however, no such model exists for s. neurona. the approach used in this study is similar to that employed for other closely related protozoal parasites such as neospora caninum and toxoplasma gondii. a time course of infection was examined, and histopathology, immunohistochemistry, and parasite isolation were used to examine the ...	1997	9272562
in vitro cultivation and experimental inoculation of sarcocystis falcatula and sarcocystis neurona merozoites into budgerigars (melopsittacus undulatus).	this is a report of the isolation and in vitro propagation of merozoites of sarcocystis falcatula. culture-derived s. falcatula merozoites remained infectious after several passages in tissue culture as determined by the susceptibility of experimentally inoculated melopsittacus undulatus that died of pulmonary sarcocystosis after experimental inoculation. there was no obvious clinical disease or lesion when sarcocystis neurona merozoites were used to inoculate m. undulatus. on the basis of the b ...	1997	9406803
sequence analysis and polymerase chain reaction amplification of small subunit ribosomal dna from sarcocystis neurona.	to identify sarcocystis neurona-specific dna sequences in the nuclear small subunit ribosomal rna (nss-rrna) gene that could be used to distinguish s neurona from other closely related protozoal parasites, and to evaluate a polymerase chain reaction (pcr) test, using broad based primers and a unique species-specific probe on csf for detection of s neurona in equids.	1996	8807006
neosporosis as a cause of equine protozoal myeloencephalitis.	neosporosis was diagnosed in an 11-year-old quarter horse gelding with clinical signs and diagnostic test results compatible with equine protozoal myeloencephalitis (epm). presumptive postmortem diagnosis of epm attributable to sarcocystis neurona infection is generally made on the basis of detecting an antibody titer to s neurona in the csf or characteristic histologic lesions, even when parasites have not been specifically identified. neosporosis was confirmed in the horse described here by us ...	1996	8944807
a sarcocystis neurona-like organism associated with encephalitis in a striped skunk (mephitis mephitis).	a sarcocystis neurona-like organism was associated with granulomatous encephalitis in an ataxic male juvenile striped skunk (mephitis mephitis) from cape cod, massachusetts. various stages of schizonts and merozoites of s. neurona were seen within some of the granulomata.	1996	8627490
identification of opossums (didelphis virginiana) as the putative definitive host of sarcocystis neurona.	sarcocystis neurona is an apicomplexan that causes equine protozoal myeloencephalitis (epm) in north and south america. horses appear to be an aberrant host, because the merozoites continually divide in the central nervous system, without encysting. the natural host species has not previously been identified. the small subunit ribosomal rna (ssurna) gene of s. neurona was compared to those of sarcocystis muris, sarcocystis cruzi, toxoplasma gondii, and cryptosporidium parvum to identify a unique ...	1995	8544064
sarcocystis falcatula from passerine and psittacine birds: synonymy with sarcocystis neurona, agent of equine protozoal myeloencephalitis.	equine protozoal myeloencephalitis (epm) is a neurologic disease of horses caused by sarcocystis neurona. the horse is a dead-end host for s. neurona and the definitive and intermediate hosts have not previously been identified. we hypothesized that s. neurona is actually sarcocystis falcatula, a parasite that cycles in nature between virginia opossums (didelphis virginiana) and any of a variety of avian intermediate hosts. we extracted dna from s. falcatula sarcocysts in the muscle of a brown-h ...	1995	8544067
phylogenetic relationship of sarcocystis neurona to other members of the family sarcocystidae based on small subunit ribosomal rna gene sequence.	sarcocystis neurona is a coccidial parasite that causes a neurologic disease of horses in north and south america. the natural host species are not known and classification is based on ultrastructural analysis. the small subunit ribosomal rna (ssurna) gene of s. neurona was amplified using polymerase chain reaction techniques and sequenced by sanger sequencing reactions. the sequence was compared with partial sequences of s. muris, s. gigantea, s. tenella, s. cruzi, s. arieticanis, s. capracanis ...	1994	7799170
differentiation of sarcocystis neurona from eight related coccidia by random amplified polymorphic dna assay.	four isolates of sarcocystis neurona from horses with equine protozoal myeloencephalitis and eight species of coccidia from the genera sarcocystis, toxoplasma or eimeria were differentiated using the random amplified polymorphic dna assay. a single, common, 550-bp dna fragment was amplified from the dna of each s. neurona isolate using a 16-nucleotide primer. crosshybridization analyses among s. neurona isolates showed that dna fragments had at least partial sequence homology. the primer generat ...	1994	7877630
encephalomyelitis due to a sarcocystis neurona-like protozoan in a rhesus monkey (macaca mulatta) infected with simian immunodeficiency virus.	a captive-born rhesus monkey (macaca mulatta) experimentally infected with simian immunodeficiency virus developed neurologic abnormalities approximately seven months postinoculation. a chronic necrotizing encephalomyelitis with intralesional protozoal schizonts was diagnosed histologically. the protozoa was identified as sarcocystis neurona based on its morphologic characteristics by light and electron microscopic examination, the developmental stages of the schizonts, and positive staining wit ...	1994	7943553
immunohistochemical study to demonstrate sarcocystis neurona in equine protozoal myeloencephalitis.	a 5-year (1985-1989) retrospective immunohistochemical study was conducted using an avidin-biotin complex (abc) immunoperoxidase method to demonstrate sarcocystis neurona in histologically suspect cases of equine protozoal myeloencephalitis (epm). primary antibodies against s. neurona and s. cruzi were utilized for the abc technique. the findings were compared with those from cases in which the organisms were detected by examination of hematoxylin and eosin (he)-stained neuronal sections. he-sta ...	1993	8373858
equine protozoal myeloencephalitis: antigen analysis of cultured sarcocystis neurona merozoites.	antigens of cultured sarcocystis neurona merozoites were examined using immunoblot analysis. blotted proteins were probed with s. cruzi, s. muris, and s. neurona antisera produced in rabbits, s. fayeri (pre- and post-infection) and s. neurona (pre- and post-inoculation) sera produced in horses, immune sera from 7 histologically confirmed cases of equine protozoal myeloencephalitis (epm), and pre-suckle serum from a newborn foal. eight proteins, 70, 24, 23.5, 22.5, 13, 11, 10.5, and 10 kd, were d ...	1993	8466988
meningoencephalitis in mink associated with a sarcocystis neurona-like organism.		1993	8373867
equine protozoal myelitis in panamanian horses and isolation of sarcocystis neurona.	schizonts of sarcocystis neurona were identified microscopically in hematoxylin-eosin-stained spinal cord sections from 2 native panamanian horses that exhibited clinical signs of equine protozoal myelitis (epm). spinal cord homogenate from a third panamanian horse with epm was inoculated onto monolayers of cultured bovine monocytes (m617). intracytoplasmic schizonts containing merozoites arranged in rosette forms surrounding a central residual body first were observed 13 wk postinoculation. par ...	1992	1403437
sarcocystis neurona-associated ataxia in horses in brazil.	sarcocystis neurona-like schizonts were found in sections of brain and spinal cord of two ataxic horses from brazil. the diagnosis was supported by staining with anti-sarcocystis serum in an immunohistochemical test. one of the affected horses was born in argentina and raised in brazil, and the other horse was born and raised in brazil.	1992	1466140
a five year (1985-1989) retrospective study of equine neurological diseases with special reference to rabies.	a retrospective study of horses necropsied between 1985 and 1989 at a diagnostic laboratory of a veterinary school in north america is documented. in this investigation over 20 per cent of the horses had clinical neurological signs. equine protozoal myeloencephalitis (caused by sarcocystis neurona) and cervical stenotic myelopathy (wobbler syndrome) were the most common of these disorders. the veterinary school is located in the midst of a raccoon rabies enzootic area. however, only four cases o ...	1992	1644935
characterization of sarcocystis neurona from a thoroughbred with equine protozoal myeloencephalitis.	morphological information is presented for syntype material of the etiologic agent of equine protozoal myeloencephalitis, sarcocystis neurona. a clinical description of the horse from which the organism was isolated and the methodology used to immunosuppress the horse in an attempt to increase parasite numbers are also given. the description includes microscopic details observed both with light and transmission electron microscopy. mainly stages from tissue are illustrated, but information is al ...	1992	1740059
sarcocystis neurona n. sp. (protozoa: apicomplexa), the etiologic agent of equine protozoal myeloencephalitis.	sarcocystis neuronan n. sp. is proposed for the apicomplexan taxon associated with myeloencephalitis in horses. only asexual stages of this parasite presently are known, and they are found within neuronal cells and leukocytes of the brain and spinal cord. the parasite is located in the host cell cytoplasm, does not have a parasitophorous vacuole, and divides by endopolygeny. schizonts are 5-35 microns x 5-20 microns and contain 4-40 merozoites arranged in a rosette around a prominent residual bo ...	1991	1901359
sarcocystis neurona cultured in vitro from a horse with equine protozoal myelitis.		1991	1915236
in vitro cultivation of sarcocystis neurona from the spinal cord of a horse with equine protozoal myelitis.	asexual stages of sarcocystis neurona were seen in cultured bovine monocytes (m617) inoculated with tissue homogenates from the spinal cord of a horse with naturally acquired protozoal myelitis. organisms first were observed as intracytoplasmic schizonts and later as motile extracellular zoites capable of infecting surrounding m617 cells. parasites most often occurred as clusters of merozoites dispersed throughout the host cell cytoplasm; however, schizonts also contained merozoites arranged in ...	1991	1919932