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Amir N. Hamir - One of the best experts on this subject based on the ideXlab platform.
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Systemic Staphylococcus aureus infection in a free-ranging raccoon (Procyon Lotor).
Journal of Wildlife Diseases, 2010Co-Authors: Amir N. HamirAbstract:Gross and histopathologic findings are described in an adult male raccoon (Procyon Lotor) with Staphylococcus aureus infection affecting several organs. At the time of necropsy the carcass was jaundiced and in poor nutritional state. A large, raised, irregular necrotic mass was present in the spleen. The liver had small multifocal, pale yellow, randomly distributed foci throughout the parenchyma. Coagulase-positive Staphylococcus aureus was cultured from both the liver and the spleen. Microscopic lesions were present in spleen, liver, kidney, and heart, which suggested systemic infection. Although S. aureus has been cultured from raccoons previously, the bacterium did not appear to have been associated with pathology. In this case, S. aureus was obtained as a pure culture, but microscopic examination did not show large numbers of bacterial colonies as seen in other species with such lesions.
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Neuroaxonal dystrophy in raccoons (Procyon Lotor) from Iowa.
Journal of Veterinary Diagnostic Investigation, 2002Co-Authors: Amir N. Hamir, Janice M. Miller, M.j. Stack, Melanie J. Chaplin, Randall C. CutlipAbstract:During a 12-month period (1998-1999), microscopic evidence of neuroaxonal dystrophy (NAD) in medullae oblongata of raccoons (Procyon Lotor) was observed in 17/39 (47% prevalence in adults) from Iowa, USA. Three of the animals were kits (3 months), 26 were between 1 and 2 years, and 10 were over 7 years. Lesions were not seen in the medullae of the 3 kits. In young adults, the lesions were mild and were seen in 7 animals. More severe lesions were present in the 10 older raccoons. Grossly, the brains were unre- markable. Microscopically, NAD was confined to the dorsal caudal medulla, where certain nuclei (predomi- nantly gracilis and cuneate) were bilaterally affected. Severely affected animals had vacuolar degeneration of neurons or neuronal loss and extensive areas of spongiosis. Tests for the presence of PrP res in the brain were negative. Spongiotic areas often contained axonal spheroids. Degenerate neurons and axons occasionally con- tained amphophilic periodic acid-Schiff-positive granular material. There was a paucity of inflammatory cells in the affected areas. Since lesions were not present in kits, were either absent or mild in young adults, and were severe in older raccoons, the findings may be related to advancing age. Neuroaxonal dystrophy has not been previously reported in raccoons. Retrospective examination of raccoon brains from the eastern and north- western areas of the country revealed very low prevalence of NAD. Because of the apparently high prevalence of this condition at this geographic location, factors other than age (genetic, nutritional, and/or environmental) may influence this degenerative process in the brains of raccoons in Iowa. Raccoons (Procyon Lotor) are found throughout North America and in some parts of Europe and Asia where they were introduced in the early 1900s from the United States. 1
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Naturally occurring spirochetes in the colonic mucosa of raccoons (Procyon Lotor).
Veterinary Pathology, 2001Co-Authors: Amir N. Hamir, Darren J. Trott, Mitchell V. Palmer, J. StaskoAbstract:The large intestines of 21 raccoons (Procyon Lotor; 11 wild caught, 10 laboratory confined) were examined for the presence of intestinal spirochetes. Light microscopy of sections stained with hematoxylin and eosin and Warthin-Starry stain showed the presence of spiral shaped organisms deep within the lumina of intestinal glands at the ileocolonic junction of 16 raccoons (76% prevalence). All laboratory-confined, group- housed raccoons harbored the organisms, but only 6/11 (55% prevalence) live-trapped raccoons were positive for these spirochetes. The organisms were free in the glandular lumina, and there were no microscopic lesions. Two types of spirochetes were identified in the colonic glands: a slender spirochete 10-13 mm in length, 0.3 mm in diameter, and possessing long, thin tapered ends and a larger, regularly waved spiral organism (0.5 mm in diameter). The slender spirochete did not resemble any of the known spirochete genera and failed to grow on medium used to propagate oral treponemes and members of the genus Brachyspira. Raccoons (Procyon Lotor) are highly adaptable nocturnal mammals that are found throughout North America and in some parts of Europe and Asia, where they were introduced in the early 1900s. 1 They share their immediate environment with humans and, therefore, are considered good monitors of infectious diseases and environmental contaminants for both humans and animals. 2,7,8
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Cerebral Larva Migrans in a Raccoon (Procyon Lotor)
Veterinary Pathology, 1999Co-Authors: Amir N. Hamir, Daniel E. Snyder, J. R. LichtenfelsAbstract:During 1997, gross and histopathologic examinations were performed on an adult female raccoon (Procyon Lotor) that was live-trapped in Corvallis, Oregon. Multifocal eosinophilic granulomas indicative of neural and visceral larva migrans were observed. However, within these granulomas, the presence of parasitic larva was seen only in the cerebrum. Morphologic characteristics indicated that the nematode was an ascarid larva. However, it was smaller than the larva of Baylisascaris sp. This appears to be the first documented case of cerebral larva migrans in a raccoon.
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Neuronal Vacuolation in Raccoons (Procyon Lotor)
Veterinary Pathology, 1997Co-Authors: Amir N. Hamir, J. R. Heidel, R. Picton, C. E. RupprechtAbstract:Microscopic vacuolar changes in neuronal perikaryon are described in two free-ranging raccoons (Procyon Lotor) from different geographic locations in the United States. Both animals were negative for rabies and scrapie-associated antigens. Microscopically, lesions were not seen in the neuropil. Neuronal vacuolations have previously been documented in brains of normal animals and in diseases such as rabies and prion-associated encephalopathies. Although experimental transmission of a spongiform mink encephalopathy has been documented in raccoons, a naturally occurring spongiform encephalopathy has not been described in this species. The presence of neuronal vacuolations in the raccoons is novel and requires further investigation to elucidate the mechanism of this phenomenon.
Charles E. Rupprecht - One of the best experts on this subject based on the ideXlab platform.
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Prevalence of Agglutinating Antibodies to Neospora caninum in Raccoons, Procyon Lotor
Journal of Parasitology, 2001Co-Authors: David S. Lindsay, Charles E. Rupprecht, Jennifer A. Spencer, Byron L. BlagburnAbstract:Neospora caninum is an apicomplexan parasite that causes neonatal neuromuscular disease in dogs and abortions in cattle. Dogs are the only proven definitive host. Little is known about the prevalence of antibodies to this parasite in wildlife. Sera from 99 raccoons (Procyon Lotor) were examined for agglutinating antibodies to N. caninum using the modified agglutination test employing formalin-fixed tachyzoites as antigen. Raccoons originated in Florida (n = 24, collected in 1996), New Jersey (n = 25, collected in 1993), Pennsylvania (n = 25, collected in 1999), and Massachusetts (n = 25, collected in 1993 and 1994). Ten (10%) had antibodies to N. caninum; 9 had titers of 1:50, and 1 (1%) had a titer of 1:100. The present study indicates that raccoons have minimal exposure to N. caninum. The sera were also tested for agglutinating antibodies to Toxoplasma gondii and 46 (46%) were positive; 16 had titers of 1:50, 8 had titers of 1:100, and 22 had titers of ≥1:500.
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Lymphosarcoma in a Raccoon (Procyon Lotor)
Journal of Wildlife Diseases, 1996Co-Authors: Amir N. Hamir, Cathleen A. Hanlon, Charles E. RupprechtAbstract:A case of lymphosarcoma in a captive adult female raccoon (Procyon Lotor) from northeastern Pennsylvania (USA) was observed in 1991. Prior to its death the raccoon had lost weight. At necropsy the carcass was in poor body condition and had pale mucous membranes. The thoracic and abdominal lymph nodes were enlarged, soft, and pale tan. Microscopically, there was effacement of normal lymph node architecture by sheets of mononuclear cells. These were well-differentiated small lymphocytes with distinct cell borders. Nuclei of these cells were darkly stained and mitotic figures were frequently seen. Similar but lesser numbers of neoplastic cells were seen in the parenchyma of liver, spleen, and the pancreas. Since the neoplasm involved several organs, we propose that the condition was of multicentric origin. Gross lesions, histopathologic findings and the organs involved differed from a previously described case of lymphosarcoma in a raccoon.
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Pyogranulomatous peritonitis associated with Nocardia sp.-like organisms in a raccoon (Procyon Lotor)
Journal of Wildlife Diseases, 1996Co-Authors: Amir N. Hamir, Charles E. RupprechtAbstract:During 1992 raccoons (Procyon Lotor) were live-trapped in northeastern Pennsylvania (USA). In one of these animals a localized pyogranulomatous peritonitis was seen. Grossly a large mass with a central area of liquifactive necrosis was present in the anterior abdomen. Microscopically the lesion contained multiple colonies of filamentous organisms with histomorphologic and histochemical charcteristics resembling Nocardia sp. This appears to be the first report of Nocardia infection in the raccoon.
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Experimental Toxoplasma gondii infection in raccoons (Procyon Lotor).
The Journal of Parasitology, 1993Co-Authors: Jitender P. Dubey, Amir N. Hamir, Shihui Shen, Thulliez P, Charles E. RupprechtAbstract:Six raccoons (Procyon Lotor) without detectable Toxoplasma gondii antibodies were used. Four raccoons were inoculated orally (2 with oocysts and 2 with tissue cysts) with ME49 strain of T. gondii and 2 raccoons were not inoculated with T. gondii. All raccoons remained clinically normal. Raccoons were killed between 59 and 61 days after inoculation and portions of their heart, skeletal muscle, and brain were digested in pepsin solution, and homogenates were bioassayed in mice. Toxoplasma gondii was isolated from all 4 inoculated raccoons; from the heart of 3, skeletal muscles of 2 and the brain of none. All 4 inoculated raccoons developed antibody titers > or = 1:1,600 in the modified direct agglutination test (MAT) using whole formalinized tachyzoites. Toxoplasma gondii antibody titers of the raccoons not inoculated with T. gondii remained < 1:25, and T. gondii was not isolated from their tissues. It was concluded that muscle tissue from multiple sites including the heart was the tissue of choice for conducting parasitologic surveys for T. gondii in raccoons. Evaluation of the sera of the experimentally infected raccoons in the Sabin-Feldman dye test, latex agglutination test, and the indirect hemagglutination tests indicated that the MAT detected antibodies faster and in higher titers than did the other serological tests.
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Pancreatic duct hyperplasia in a raccoon (Procyon Lotor) caused by Atriotaenia Procyonis.
Journal of Wildlife Diseases, 1991Co-Authors: Daniel E. Snyder, Amir N. Hamir, Cathleen A. Hanlon, Charles E. RupprechtAbstract:A raccoon (Procyon Lotor) live-trapped in Philadelphia, Pennsylvania was heavily infected with the tapeworm Atriotaenia Procyonis. Histopathologic examination of the duodenum revealed this tapeworm attached to the mucosa; the mucosa was mildly hyperplastic without a significant inflammatory infiltrate. This tapeworm was seen also within the proximal pancreatic duct and histopathologic lesions associated with its presence consisted of marked hyperplasia of mucosal cells, causing the formation of an extensive papillary projection into the duct lumen. Inflammatory cellular reaction was minimal, consisting primarily of lymphocytes, and was seen in the mucosa and submucosa of the duct. The presence of A. Procyonis in the pancreas of this raccoon is considered to be an aberrant location for this parasite and has not been reported previously.
Mark E. Ritke - One of the best experts on this subject based on the ideXlab platform.
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Geographic Variation of Sexual Dimorphism in the Raccoon Procyon Lotor
American Midland Naturalist, 1993Co-Authors: Mark E. Ritke, Michael L. KennedyAbstract:-Geographic variation of sexual dimorphism for 22 cranial characters was investigated in raccoons (Procyon Lotor) from 87 localities. Geographic variation in the degree of sexual dimorphism occurred only for canine width and the degree of sexual dimorphism in canine width was significantly less for raccoons from W of the Continental Divide than those from E of the Continental Divide. The lack of geographic variation in sexual dimorphism of greatest length of skull indicates that sexual dimorphism in body size of raccoons also does not vary geographically (skull length is highly correlated with body size). Thus, it appears that selection pressures responsible for sexual dimorphism in raccoons are acting uniformly throughout much of the range of the species. Geographic variation in the degree of sexual dimorphism for canine width may be the result of geographic variation in the intensity of intrasexual selection (i.e., variation in the intensity of male-male competition for mates during the breeding season). If so, the apparent lack of geographic variation in sexual size dimorphism of raccoons may indicate that male body size is not under the same kinds of selection pressures (e.g., intrasexual selection) as canine size.
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Quantitative Assessment of Variation in Litter Size of the Raccoon Procyon Lotor
American Midland Naturalist, 1990Co-Authors: Mark E. RitkeAbstract:-Geographic variation in litter size of the raccoon (Procyon Lotor) is positively correlated with latitude, longitude and female body size. The positive correlation between litter size and body size for raccoons is inconsistent with interspecific patterns of litter sizebody size variation of carnivores in which litter size decreases with increasing body size. Multiple regression analysis revealed that only body size explains a significant amount of the variation in raccoon litter size. Geographic variation in litter size of raccoons occurs because there is geographic variation in female body size whereas climatic factors associated with latitude and longitude appear to influence litter size only indirectly via their effects on
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Sexual Dimorphism in the Raccoon (Procyon Lotor): Morphological Evidence for Intrasexual Selection
American Midland Naturalist, 1990Co-Authors: Mark E. RitkeAbstract:-Relative sexual dimorphism in measurements of 21 cranial dimensions of the raccoon (Procyon Lotor) was analyzed using least squares regression analysis. Males were larger than females for all dimensions but were found to be larger than females for only seven such dimensions when controlling for skull size; females were relatively larger than males for 12 dimensions. This study indicates that intrasexual selection (male-male competition for access to females) is a viable explanation of why male raccoons are larger than females because males are relatively larger for characters that relate to male-male combat. However, it is also possible that sexual dimorphism in P. Lotor is partly the result of intersexual selection (female "choice" of larger males). Although this study agrees with previous interpretations of sexual dimorphism in P. Lotor, it points out the utility of examining relative patterns of sexual dimorphism before inferring the role of intrasexual selection.
F. Blake Morton - One of the best experts on this subject based on the ideXlab platform.
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Do wild raccoons (Procyon Lotor) use tools?
Animal Cognition, 2020Co-Authors: F. Blake MortonAbstract:Being able to make and use tools was once considered to be an evolutionary hallmark of our species, but has since been documented in other animals. However, for reasons that remain unclear, not all species naturally use tools. Racoons ( Procyon Lotor ) are generalist carnivores that possess many of the physical, cognitive, and behavioural characteristics linked to tool use in other species (e.g. manual dexterity, tactile exploration, relatively large brains, extractive foraging, and sociality). Although raccoons have not been observed using tools outside of experimental captive conditions, wild data involving objective psychometric tests are needed. The current study administered a tool-related task to a wild population of raccoons from 20 locations within the Croatan National Forest, USA. The task required participants to use a stick to extract food from a pipe. To facilitate interpretations of their performances on the task, data were obtained on natural tool availability at the field site and participants’ mode of exploring the novel task. None of the participants solved the task despite natural sticks (suitable for solving the task) being widely available across testing locations. Participants were equally likely to smell versus handle novel sticks, which were provided at testing platforms. Limited tactile exploration, but not tool availability, could be at least one factor that reduces these raccoons’ opportunities to interact with and learn about novel tools like sticks.
Michael L. Kennedy - One of the best experts on this subject based on the ideXlab platform.
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Temporal Genetic Variation in the Raccoon, Procyon Lotor
Journal of Mammalogy, 1998Co-Authors: Susan E. White, Phyllis K. Kennedy, Michael L. KennedyAbstract:Starch-gel electrophoresis was used to assess temporal genetic variation in a population of raccoon, Procyon Lotor . Specimens ( n = 1,056) were collected during nine annual hunts (1984–1992) at Reelfoot National Wildlife Refuge, Obion Co., Tennessee, and Fulton Co., Kentucky. Of 41 loci examined, 35 were monomorphic; 6 exhibited polymorphism and were used in statistical analyses. Heterozygosity ranged from 0.033 (1990) to 0.046 (1992) with a mean of 0.042; however, differences across years were not significant. Significant deviations from Hardy-Weinberg equilibrium were minimal. Chi-square contingency analysis revealed significant differences in allelic frequencies among years for four of the six polymorphic loci. Wright's F -statistics indicated significant differentiation among years ( F st = 0.042). Rogers’ genetic similarity coefficients ranged from 0.836 to 0.973. The matrix of all pairwise comparisons indicated a random pattern of relationships among years. Hunting appears to have had little influence on the genetic composition of raccoons in the study area over the 9-year period. The observed pattern of low-level temporal variation is probably the result of stochastic events.
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Geographic Variation of Sexual Dimorphism in the Raccoon Procyon Lotor
American Midland Naturalist, 1993Co-Authors: Mark E. Ritke, Michael L. KennedyAbstract:-Geographic variation of sexual dimorphism for 22 cranial characters was investigated in raccoons (Procyon Lotor) from 87 localities. Geographic variation in the degree of sexual dimorphism occurred only for canine width and the degree of sexual dimorphism in canine width was significantly less for raccoons from W of the Continental Divide than those from E of the Continental Divide. The lack of geographic variation in sexual dimorphism of greatest length of skull indicates that sexual dimorphism in body size of raccoons also does not vary geographically (skull length is highly correlated with body size). Thus, it appears that selection pressures responsible for sexual dimorphism in raccoons are acting uniformly throughout much of the range of the species. Geographic variation in the degree of sexual dimorphism for canine width may be the result of geographic variation in the intensity of intrasexual selection (i.e., variation in the intensity of male-male competition for mates during the breeding season). If so, the apparent lack of geographic variation in sexual size dimorphism of raccoons may indicate that male body size is not under the same kinds of selection pressures (e.g., intrasexual selection) as canine size.