Author
Speer Ca
Bio: Speer Ca is an academic researcher from University of Tennessee. The author has contributed to research in topics: Neospora caninum & Paratuberculosis. The author has an hindex of 17, co-authored 18 publications receiving 2366 citations.
Papers
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TL;DR: A newly identified parasite, Neospora caninum, structurally distinct from T gondii, was found in 10 dogs and formed meronts in many tissues of the dogs, especially the brain and spinal cord.
Abstract: Histologic sections and case histories from 23 dogs with proven fatal toxoplasmosis-like illness at the Angell Memorial Animal Hospital were reviewed. Toxoplasma gondii was identified in 13 dogs. A newly identified parasite, Neospora caninum, structurally distinct from T gondii, was found in 10 dogs. The newly discovered organism, belonging to a new genus and new species, formed meronts in many tissues of the dogs, especially the brain and spinal cord. Neospora caninum was located directly in the host cell cytoplasm without a parasitophorous vacuole; it divided by endodyogeny, contained more than 11 rhoptries, and did not react with the anti-T gondii serum in the immunoperoxidase test. Meningoencephalomyelitis and myositis were the main lesions associated with N caninum. Ulcerative and fistulous dermatitis was the major lesion in 1 dog.
787 citations
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15 Oct 2015TL;DR: Sarcocystosis of animals and man, SarcocyStosis ofAnimals and man , مرکز فناوری اطلاعات و اصاع رسانی, کδاوρزی
Abstract: Sarcocystis is one of the most prevalent parasites of livestock and also infects many wild mammals, birds, and humans. Written by the authors who pioneered studies of Sarcocystosis of domestic animals, Sarcocystosis of Animals and Humans, Second Edition provides a current and comprehensive review of Sarcocystis and the infections it causes in anima
623 citations
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TL;DR: Sarcocystis neuronan n.
Abstract: 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 body. Merozoites are approximately 4 x 1 micron, have a central nucleus, and lack rhoptries. Schizonts and merozoites react with Sarcocystis cruzi antiserum but not with Caryospora bigenetica. Toxoplasma gondii, Hammondia hammondi, or Neospora caninum antisera in an immunohistochemical test.
239 citations
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United States Department of Agriculture1, University of California, Davis2, Ontario Veterinary College3, Norwegian University of Life Sciences4, Swedish University of Agricultural Sciences5, Cornell University6, Auburn University7, University of Technology, Sydney8, University of Bern9, University of Kentucky10, Obihiro University of Agriculture and Veterinary Medicine11, Academy of Sciences of the Czech Republic12, University of Veterinary and Pharmaceutical Sciences Brno13, University of Missouri14, University of Illinois at Urbana–Champaign15, Washington University in St. Louis16, University of Tennessee17, Liverpool School of Tropical Medicine18, Kansas State University19, Virginia–Maryland Regional College of Veterinary Medicine20
TL;DR: The authors redescribe the parasite, distinguish it from related coccidia, and provide accession numbers to its type specimens deposited in museums.
225 citations
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TL;DR: Comparison of N caninum with Toxoplasma gondii tachyzoites indicated that the 2 species can be differentiated on the basis of structure and numbers fo rhoptries and numbers and location of micronemes and electron-dense bodies.
Abstract: The ultrastructure of tachyzoites of 3 isolates of Neospora caninum from dogs was examined, using transmission electron microscopy of infected cultured cells. Ultrastructure of the 3 isolates was similar. Tachyzoites had a pellicle, 22 subpellicular microtubules, a conoid, anterior and posterior polar rings, 8 to 12 electron-dense rhoptries, numerous micronemes, a single vesicular nucleus, tubular mitochondria, Golgi complexes, ribosomes, endoplasmic reticula, an inactive micropore, electron-dense bodies, lipid bodies, and amylopectin bodies. Most tachyzoites were located adjacent to the host cell nucleus in a parasitophorous vacuole that contained numerous intravacuolar tubules. Tachyzoites divided by endodyogeny. Neospora caninum tissue cysts were not seen. Comparison of N caninum with Toxoplasma gondii tachyzoites indicated that the 2 species can be differentiated on the basis of structure and numbers fo rhoptries and numbers and location of micronemes and electron-dense bodies.
82 citations
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TL;DR: A detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse is provided.
Abstract: Infections by the protozoan parasite Toxoplasma gondii are widely prevalent world-wide in animals and humans. This paper reviews the life cycle; the structure of tachyzoites, bradyzoites, oocysts, sporocysts, sporozoites and enteroepithelial stages of T. gondii; and the mode of penetration of T. gondii. The review provides a detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse. The mechanism of in vivo and in vitro stage conversion from sporozoites to tachyzoites to bradyzoites and from bradyzoites to tachyzoites to bradyzoites is also discussed.
1,103 citations
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TL;DR: Dogs are a definitive host of Neospora caninum, and mice inoculated with canine faecal extracts were monitored for evidence of neosporosis using a variety of morphologic, immunohistologic, serologic, and genetic analyses.
1,069 citations
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TL;DR: This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated.
Abstract: Neospora caninum is a protozoan parasite of animals. Until 1988, it was misidentified as Toxoplasma gondii. Since its first recognition in dogs in 1984 and the description of the new genus and species Neospora caninum in 1988, neosporosis has emerged as a serious disease of cattle and dogs worldwide. Abortions and neonatal mortality are a major problem in livestock operations, and neosporosis is a major cause of abortion in cattle. Although antibodies to N. caninum have been reported, the parasite has not been detected in human tissues. Thus, the zoonotic potential is uncertain. This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated. The role of wildlife in the life cycle of N. caninum and strategies for the control of neosporosis in cattle are discussed.
977 citations
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TL;DR: Neospora caninum is a recently recognized protozoan parasite of animals, which until 1988 was misidentified as Toxoplasma gondii, and its life cycle is unknown.
963 citations
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TL;DR: Seroprevalence of T. gondii in humans and pigs is declining and Modes of transmission, epidemiology and environmental contamination with oocysts on land and sea are discussed.
945 citations