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1.
Vet Pathol ; 60(4): 420-433, 2023 07.
Article in English | MEDLINE | ID: mdl-37199487

ABSTRACT

Chronic wasting disease (CWD) is an infectious transmissible spongiform encephalopathy of cervids associated with the presence of a misfolded prion protein (PrPCWD). Progression of PrPCWD distribution has been described using immunohistochemistry and histologic changes in a single section of brain stem at the level of the obex resulting in scores from 0 (early) to 10 (terminal) in elk with naturally occurring CWD. Here we describe the spread and distribution of PrPCWD in peripheral tissues and spinal cord in 16 wild and 17 farmed Rocky Mountain elk (Cervus elaphus nelsoni) with naturally occurring CWD and correlate these findings with obex scores. Spinal cord and approximately 110 peripheral tissues were collected, processed, stained with hematoxylin and eosin, and immunolabeled with the anti-prion protein monoclonal antibody F99/97.6.1. The medial retropharyngeal and tracheobronchial lymph nodes were the first tissues to accumulate PrPCWD, followed by other lymphoid tissues, myenteric plexus, spinal cord, and finally tissues outside of the lymphatic and neural systems. However, the only significant histological lesion observed was mild spongiform encephalopathy in the dorsal column of the lower spinal cord in elk with an obex score of ≥9. Initial exposure to CWD prions may be through the respiratory system and spread appears to occur primarily via the autonomic nervous system. Therefore, we suggest using obex scores as a proxy for stage of disease progression and verifying with key peripheral tissues.


Subject(s)
Deer , Prion Diseases , Prions , Wasting Disease, Chronic , Animals , Wasting Disease, Chronic/pathology , Prion Proteins , Prion Diseases/veterinary , Spinal Cord/pathology , Protein Isoforms/metabolism
2.
Parasitol Res ; 117(4): 1079-1086, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29435720

ABSTRACT

A parasitological survey of 651 northern fur seals Callorhinus ursinus L. from five subpopulations was conducted on St. Paul Island, Alaska, during July-August 2012-2014. Digenean trematodes were found in 210 of 651 fur seals with a total prevalence of 32.3%. Intensity of infection varied from 1 to 1540 parasites with mean intensity 18.4 ± 111.1 SD and median intensity of 2 specimens per host. Significant differences in prevalence and intensity of infection in northern fur seals between separate rookeries was not observed (Mann-Whitney test; p > 0.05). Four species of digeneans belonging to the families Heterophyidae (Apophallus zalophi Price, 1932, Phocitrema fusiforme Goto and Ozaki, 1930, and Galactosomum ubelakeri (Dailey, 1969)) and Troglotrematidae (Nanophyetus salmincola (Chapin, 1926)) were found. Nanophyetus salmincola is reported from C. ursinus for the first time. We obtained partial 28S rDNA sequences for all digenean species and conducted molecular phylogenetic analysis to demonstrate their phylogenetic relationships.


Subject(s)
Fur Seals/parasitology , Heterophyidae/classification , Trematode Infections/epidemiology , Trematode Infections/veterinary , Troglotrematidae/classification , Alaska/epidemiology , Animals , Heterophyidae/genetics , Heterophyidae/isolation & purification , Intestines/parasitology , Phylogeny , Prevalence , RNA, Ribosomal, 28S/genetics , Trematode Infections/parasitology , Troglotrematidae/genetics , Troglotrematidae/isolation & purification
3.
Vet Pathol ; 54(2): 258-268, 2017 03.
Article in English | MEDLINE | ID: mdl-27543449

ABSTRACT

A previously unrecognized condition is described in wild free-ranging Pribilof arctic foxes ( Alopex lagopus pribilofensis) from the Pribilof Islands, Alaska, USA. This condition is called shaggy lame fox syndrome (SLFS) denoting the primary clinical signs first observed. Criteria used to suspect SLFS on gross examination included emaciation, failure to shed winter pelage and moderate to severe polyarthritis. Criteria used to confirm SLFS histologically included polyarthritis (characterized by lymphoplasmacytic synovitis, tenosynovitis, bursitis, periosteal bony proliferation, and periarticular lymphoplasmacytic vasculitis) and systemic leukocytoclastic vasculitis. Other histological lesions often found included renal cortical infarcts, myocarditis with myocardial infarcts, lymphoplasmacytic meningitis, lymphoplasmacytic cuffing of meningeal and a few cerebral vessels, and cavitating infarcts of the brainstem and thalamus. The cause of SLFS is not known at this time; however, the gross and histological lesions suggest that the cause of SLFS may be a bacterial polyarthritis with a secondary immune-mediated vasculitis. These lesions are consistent with changes described with Erysipelothrix rhusiopathiae in domestic dogs; E. rhusiopathiae was identified from the synovial membrane of a swollen stifle joint and the kidney from one fox using real-time polymerase chain reaction and with culture from a fox that had gross and histological lesions of SLFS. Therefore, E. rhusiopathiae is a possible etiological agent for SLFS.


Subject(s)
Arthritis/veterinary , Foxes , Hair , Islands , Alaska/epidemiology , Animals , Arthritis/epidemiology , Arthritis/pathology
4.
Vet Pathol ; 53(6): 1164-1171, 2016 11.
Article in English | MEDLINE | ID: mdl-27020536

ABSTRACT

Bighorn sheep sinus tumors are a recently described disease affecting the paranasal sinuses of Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Several features of this disease suggest an infectious cause, although a specific etiologic agent has not been identified. To test the hypothesis that bighorn sheep sinus tumors are caused by an infectious agent, we inoculated 4 bighorn sheep lambs and 4 domestic sheep lambs intranasally with a cell-free filtrate derived from a naturally occurring bighorn sheep sinus tumor; we held 1 individual of each species as a control. Within 18 months after inoculation, all 4 inoculated domestic sheep (100%) and 1 of the 4 inoculated bighorn sheep (25%) developed tumors within the ethmoid sinuses or nasal conchae, with features similar to naturally occurring bighorn sheep sinus tumors. Neither of the uninoculated sheep developed tumors. Histologically, the experimentally transmitted tumors were composed of stellate to spindle cells embedded within a myxoid matrix, with marked bone production. Tumor cells stained positively with vimentin, S100, alpha smooth muscle actin, and osteocalcin, suggesting origin from a multipotent mesenchymal cell. A periosteal origin for these tumors is suspected. Immunohistochemical staining for the envelope protein of JSRV (with cross-reactivity to ENTV) was equivocal, and PCR assays specific for these agents were negative.


Subject(s)
Paranasal Sinus Neoplasms/veterinary , Sheep Diseases/transmission , Animals , Female , Male , Paranasal Sinus Neoplasms/diagnostic imaging , Paranasal Sinus Neoplasms/etiology , Paranasal Sinus Neoplasms/pathology , Paranasal Sinuses/pathology , Sheep , Sheep Diseases/diagnostic imaging , Sheep Diseases/etiology , Sheep Diseases/pathology , Sheep, Bighorn , Sheep, Domestic , Tomography, X-Ray Computed/veterinary
5.
Parasitol Res ; 113(12): 4463-70, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25216781

ABSTRACT

Anisakid nematodes parasitize the alimentary tracts of aquatic vertebrates, including northern fur seals (Callorhinus ursinus) (NFS). The main purpose of this study was to estimate the prevalence, intensity, and species composition of anisakids in NFSs on St. Paul Island, Alaska, and to analyze changes in NFS infection with these nematodes during the last decades. The study was carried out on St. Paul Island, Alaska, in July-August 2011-2013. Stomachs of 443 humanely harvested NFS males were collected from five separate haul-out areas. A total of 4,460 anisakid specimens were collected and identified by morphological criteria. Gross and histological examinations of stomachs were also performed. The overall prevalence of NFS infection was 91.2%; overall mean intensity 10.9, and overall median intensity 6. Five species, Anisakis simplex s. l., Contracaecum osculatum s. l., Pseudoterranova decipiens s. l., P. azarazi and Phocascaris cystophorae, were found. The prevalence of Anisakis was 46.5%, its intensity 7.5. The prevalence and intensity of Contracaecum, Pseudoterranova, and Phocascaris were 33.6% and 3.5, 81.9% and 6.5, and 5.2% and 1.7, respectively. Significant differences in the prevalence of NFS infection were observed between separate haul-outs. Comparison of the present data with the results of studies performed in the North Pacific in the 1960s, showed a significant decrease in the intensity of NFS infection with anisakids during the last decades. The prevalence of mucosal lesions in NFS stomachs caused by anisakids also decreased from 92 to 20.9%. Possible reasons for the changes in NFS infection with anisakids are discussed.


Subject(s)
Ascaridida Infections/veterinary , Ascaridoidea/isolation & purification , Fur Seals/parasitology , Gastric Mucosa/pathology , Gastric Mucosa/parasitology , Alaska/epidemiology , Animals , Ascaridida Infections/epidemiology , Ascaridida Infections/parasitology , Ascaridida Infections/pathology , Ascaridoidea/anatomy & histology , Ascaridoidea/classification , Islands , Male , Prevalence
6.
J Comp Pathol ; 150(2-3): 306-15, 2014.
Article in English | MEDLINE | ID: mdl-24060152

ABSTRACT

The aim of this study was to test the hypothesis that oxidative stress and glutamine synthetase (GS) redistribution occur in domoic acid (DA) toxicosis in California sea lions (CSLs, Zalophus californianus). Sections of archived hippocampi from seven control and 13 CSLs diagnosed with DA toxicosis were labelled immunohistochemically for GS and for two markers of oxidative stress, malondialdehyde (MDA) and 3-nitrotyrosine (NT). The distribution and intensity of labelling were compared with the pathological changes seen in haematoxylin and eosin-stained sections. Increased expression of MDA and NT occurred in neurons of the hippocampal formation of CSLs with lesions consistent with DA toxicosis. The degree of oxidative stress was not affected significantly by the chronicity or severity of hippocampal damage. In six out of seven CSLs with chronic effects of DA toxicosis, in addition to the normal glial distribution of GS, GS expression was very strong in some neurons of the subiculum. However, neuronal GS labelling was also seen in one control CSL, an effect that may have been due to previous exposure to DA. GS expression in neurons was associated with decreases in GS labelling in neighbouring glial cell processes. DA toxicosis therefore induces increased expression of markers of oxidative stress in neurons consistent with oxidative stress contributing to the initial DA insult and also the epilepsy that often develops in chronic DA toxicosis. GS redistribution occurred primarily in chronic DA toxicosis, perhaps leading to alterations of the glutamine-glutamate-GABA (gamma-aminobutyric acid) cycle and contributing to the excitotoxicity and seizures often seen in DA toxicosis.


Subject(s)
Glutamate-Ammonia Ligase/metabolism , Hippocampus/drug effects , Kainic Acid/analogs & derivatives , Neurons/drug effects , Oxidative Stress/drug effects , Animals , Hippocampus/metabolism , Kainic Acid/toxicity , Malondialdehyde/metabolism , Neurons/metabolism , Oxidative Stress/physiology , Sea Lions , Tyrosine/analogs & derivatives , Tyrosine/metabolism
7.
Parasitol Res ; 112(9): 3091-100, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23760875

ABSTRACT

Studies of northern fur seal (Callorhinus ursinus Linnaeus, 1758) infection by the filariid nematode Acanthocheilonema odendhali were carried out in 2011-2012 on St. Paul Island, Pribilof Archipelago, Alaska. Skins of 502 humanely harvested northern fur seals from haul-out areas of five rookeries, Polovina (n = 122), Morjovi (n = 54), Zapadni (n = 72), Lukanin (n = 109), and Gorbatch (n = 145), were examined. A. odendhali was found in 18% of northern fur seals. The prevalence of infection ranged from 12.5% up to 22.9% on different haul-out areas on the island. The mean intensity of infection was 1.3 (range 1-7). Detailed morphological examination of collected specimens was performed using light microscopy. Several characters were added to the morphological description of the species, among them lateral thickening of the body cuticle, especially prominent in males, variations in number and position of genital papillae in males, transverse striation of the cuticle, and terminal dilation on tail end in microfilariae. The adult specimens studied had a shorter esophagus than type specimens from the California sea lion described by Perry (1967). Comparison of partial sequences of the mitochondrial cox1 gene from specimens collected from five sampling sites on St. Paul Island and a specimen from the type host and territory in California showed no significant differences and strongly supported conspecificity of the material from Alaska with A. odendhali.


Subject(s)
Acanthocheilonema , Acanthocheilonemiasis/veterinary , Fur Seals/parasitology , Acanthocheilonema/anatomy & histology , Acanthocheilonema/genetics , Acanthocheilonema/isolation & purification , Acanthocheilonema/physiology , Acanthocheilonemiasis/epidemiology , Acanthocheilonemiasis/parasitology , Alaska/epidemiology , Animals , Base Sequence , California , Electron Transport Complex IV/genetics , Female , Male , Microfilariae , Mitochondrial Proteins/genetics , Molecular Sequence Data , Prevalence , Sequence Analysis, DNA
8.
Transbound Emerg Dis ; 60(4): 345-50, 2013 Aug.
Article in English | MEDLINE | ID: mdl-22747976

ABSTRACT

In 2010, Coxiella burnetii was identified at a high prevalence in the placentas of Northern fur seals (Callorhinus ursinus) collected at a single rookery on St. Paul Island Alaska; an area of the United States where the agent was not known to be present. As contamination was hypothesized as a potential cause of false positives, but nothing was known about environmental C. burnetii in the region, an environmental survey was conducted to look for the prevalence and distribution of the organism on the island. While environmental prevalence was low, two strains of the organism were identified using PCR targeting the COM1 and IS1111 genes. The two strains are consistent with the organism that has been increasingly identified in marine mammals as well as a strain type more commonly found in terrestrial environments and associated with disease in humans and terrestrial animals. Further work is needed to elucidate information regarding the ecology of this organism in this region, particularly in association with the coastal environment.


Subject(s)
Coxiella burnetii/classification , Environment , Fur Seals/microbiology , Q Fever/epidemiology , Alaska/epidemiology , Animals , Coxiella burnetii/genetics , Coxiella burnetii/isolation & purification , DNA, Bacterial/genetics , Islands , Polymerase Chain Reaction , Prevalence , Q Fever/microbiology , Q Fever/veterinary
9.
Vet Pathol ; 50(4): 622-5, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23125144

ABSTRACT

In 2010, Coxiella burnetii was identified in 75% of northern fur seal placentas from a single rookery in Alaska, but nothing was known about the significance of this organism in the population. Although many infectious organisms cause increased cell death, C. burnetii has been shown to suppress apoptosis of the host macrophages as an intracellular survival mechanism. To determine if infection induces a similar functional change in the placenta, immunohistochemistry for antibodies to cleaved caspase-3 (activated caspase-3) and the (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) technique were used to compare the amount of placental apoptosis in infected and noninfected placentas. There was a statistically significant difference in the frequency of apoptotic cells between infected and uninfected placentas, with more apoptosis identified in the uninfected placentas. This finding suggests that the survival mechanism of C. burnetii in host macrophages to reduce apoptosis may also be utilized in trophoblasts. The significance of decreased trophoblastic apoptosis for the northern fur seal fetus requires further investigation.


Subject(s)
Apoptosis , Coxiella burnetii/physiology , Fur Seals/physiology , Placenta/microbiology , Q Fever/veterinary , Alaska , Animals , Caspase 3/analysis , Caspase 3/immunology , Coxiella burnetii/isolation & purification , Female , Fur Seals/microbiology , Immunohistochemistry/veterinary , In Situ Nick-End Labeling/methods , In Situ Nick-End Labeling/veterinary , Placenta/pathology , Pregnancy , Q Fever/pathology , Trophoblasts/microbiology , Trophoblasts/pathology
10.
Parasitol Res ; 111(3): 1049-58, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22584377

ABSTRACT

Monitoring studies of acanthocephalans in northern fur seals (Callorhinus ursinus Linnaeus, 1758) (NFSs) and a harbor seal (Phoca vitulina Linnaeus, 1758) were performed on St. Paul Island, Alaska, in July-August 2011. Gastrointestinal tracts of 105 humanely harvested NFS subadult males (SAMs) (3-4 years old) were collected during the annual Aleut subsistence harvest at four haul-out areas (HOAS): Lukanin (n = 26 NFSs), Polovina (n = 28), Gorbatch (n = 30), and Morzhovyi (n = 21). One gastrointestinal tract collected from a harbor seal (about 3-4 years old) found dead at Morzhovyi HOAS was also examined. The total prevalence of infection in NFSs with acanthocephalans was 29.52 % with variations from 7.69 % to 47.62 % between the four different HOAS. Eight acanthocephalan species of two genera-Corynosoma Lühe, 1904 (Corynosoma strumosum, Corynosoma alaskensis, Corynosoma cameroni, Corynosoma semerme, Corynosoma similis, Corynosoma validum, and Corynosoma villosum), and Bolbosoma Porta, 1908 (Bolbosoma nipponicum)-were found in the NFSs and a harbor seal. This is a new record of C. alaskensis for the NFSs. Short biological notes of the species found are presented. Differences in species composition as well as in prevalence of acanthocephalans parasitizing NFSs were observed in subpopulations from four different HOAS on St. Paul Island. The highest biodiversity of acanthocephalans and infection were found in subpopulations on Polovina and Morzhovyj HOAS, the lowest was on Lukanin HOAS. From 3.2 % (for C. validum) to 19.4 % (for C. villosum) of NFSs were infected by one acanthocephalan species; two species were found in 22.6 %; three in 9.7 %; and four in 3.2 %. Further studies of NFS parasites are necessary to follow the trends in parasitic infection rates and diversity in NFS population on the Pribilov Islands and for monitoring the influence of various ecological factors on NFS populations in Alaska.


Subject(s)
Acanthocephala/classification , Acanthocephala/isolation & purification , Fur Seals , Helminthiasis, Animal/parasitology , Acanthocephala/ultrastructure , Alaska/epidemiology , Animals , Biodiversity , Demography , Female , Helminthiasis, Animal/epidemiology , Islands , Male , Prevalence , Species Specificity
11.
Theriogenology ; 78(4): 830-41, 2012 Sep 01.
Article in English | MEDLINE | ID: mdl-22541328

ABSTRACT

Gonadotropin-releasing hormone is intermittently released from the hypothalamus in consistent patterns from before birth to final maturation of the hypothalamic-pituitary-gonadal axis at puberty. Disruption of this signaling via GnRH vaccination during the neonatal period can alter reproduction at maturity. The objective of this study was to investigate the long-term effects of GnRH-antibody exposure on reproductive maturation and function in elk calves passively exposed to high concentrations of GnRH antibodies immediately after birth. Fifteen elk calves (eight males and seven females) born to females treated with GnRH vaccine or sham vaccine during midgestation were divided into two groups based on the concentration of serum GnRH antibodies measured during the neonatal period. Those with robust (>15 pmol (125)I-GnRH bound per mL of serum) titers (N = 10; four females and six males) were designated as the exposed group, whereas those with undetectable titers (N = 5; three females and two males) were the unexposed group. Onset of puberty, reproductive development, and endocrine function in antibody-exposed and unexposed male and female elk calves were compared. Neonatal exposure to high concentrations of GnRH antibodies had no effect on body weight (P = 0.968), endocrine profiles (P > 0.05), or gametogenesis in either sex. Likewise, there were no differences between groups in gross or histologic structure of the hypothalamus, pituitary, testes, or ovaries. Pituitary stimulation with a GnRH analog before the second potential reproductive season induced substantial LH secretion in all experimental elk. All females became pregnant during their second reproductive season and all males exhibited similar mature secondary sexual characteristics. There were no differences between exposure groups in hypothalamic GnRH content (P = 0.979), pituitary gonadotropin content (P > 0.05) or gonadal structure. We concluded that suppressing GnRH signaling through immunoneutralization during the neonatal period likely does not alter long-term reproductive function in this species.


Subject(s)
Antibodies/metabolism , Antibodies/pharmacology , Deer , Gonadotropin-Releasing Hormone/immunology , Pregnancy, Animal , Reproduction/drug effects , Animals , Animals, Wild , Antibodies/therapeutic use , Contraception/adverse effects , Contraception/veterinary , Deer/physiology , Diffusion , Female , Male , Maternal-Fetal Exchange/drug effects , Maternal-Fetal Exchange/immunology , Pregnancy , Pregnancy, Animal/immunology , Prenatal Exposure Delayed Effects/chemically induced , Prenatal Exposure Delayed Effects/immunology , Prenatal Exposure Delayed Effects/physiopathology , Reproduction/immunology , Reproduction/physiology , Sexual Maturation/immunology , Sexual Maturation/physiology , Vaccines, Contraceptive/administration & dosage , Vaccines, Contraceptive/adverse effects , Vaccines, Contraceptive/pharmacokinetics , Vaccines, Contraceptive/pharmacology
12.
Parasitol Res ; 111(4): 1847-50, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22543700

ABSTRACT

Northern elephant seals (Mirounga angustirostris Gill, 1866), inhabiting rookeries on the mainland of Año Nuevo State Reserve in central California, were investigated in 2012 for presence of hookworms (Uncinaria spp.). Material collected and examined for hookworms included: blubber (n = 15), stomach and intestines (n = 21) from dead pups; feces from the rectum of weaned pups (n = 23); sand containing apparent feces in areas of weaned pups (n = 28) and sand without apparent feces in areas of weaned pups (n = 54); milk from females (n =23) at 5 days and about 23 to 26 days postpartum; and placenta from one female. Evidence of hookworm presence was not detected in any of the samples examined. Possible reasons why hookworms were not found in northern elephant seals on the mainland of Año Nuevo State Reserve are discussed.


Subject(s)
Ancylostomatoidea/isolation & purification , Hookworm Infections/veterinary , Seals, Earless/parasitology , Animal Structures/parasitology , Animals , California , Feces/parasitology , Female , Hookworm Infections/parasitology , Male , Milk/parasitology , Soil/parasitology
14.
Vet Pathol ; 49(5): 771-4, 2012 Sep.
Article in English | MEDLINE | ID: mdl-21900543

ABSTRACT

Lymphoma in the left femoral nerve of a 10-year-old English Cocker Spaniel caused complete paralysis of the affected limb. Neoplastic cells were immunopositive for CD79a and Pax5 and negative for CD3. Neoplastic cells were in multiple lymph nodes and one kidney but spared bone marrow. The clinical and histologic features in this case resemble those of the rare human condition of neurolymphomatosis.


Subject(s)
Dog Diseases/diagnosis , Femoral Nerve/pathology , Lymphoma, B-Cell/veterinary , Peripheral Nervous System Diseases/veterinary , Animals , CD79 Antigens/immunology , Diagnosis, Differential , Dog Diseases/immunology , Dog Diseases/pathology , Dogs , Extremities/pathology , Fatal Outcome , Female , Femoral Artery/pathology , Immunohistochemistry/veterinary , Immunophenotyping/veterinary , Kidney/pathology , Lymph Nodes/immunology , Lymph Nodes/pathology , Lymphoma, B-Cell/diagnosis , Lymphoma, B-Cell/immunology , Lymphoma, B-Cell/pathology , Neoplastic Cells, Circulating/pathology , PAX5 Transcription Factor/immunology , Paralysis , Peripheral Nervous System Diseases/diagnosis , Peripheral Nervous System Diseases/immunology , Peripheral Nervous System Diseases/pathology
15.
Vet Pathol ; 48(6): 1061-74, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21383115

ABSTRACT

West Nile virus (WNV)-associated disease has a range of clinical manifestations among avian taxa, the reasons for which are not known. Species susceptibility varies within the avian family Corvidae, with estimated mortality rates ranging from 50 to 100%. We examined and compared virologic, immunologic, pathologic, and clinical responses in 2 corvid species, the American crow (Corvus brachyrhynchos) and the fish crow (C ossifragus), following experimental WNV inoculation. Unlike fish crows, which remained clinically normal throughout the study, American crows succumbed to WNV infection subsequent to dehydration, electrolyte and pH imbalances, and delayed or depressed humoral immune responses concurrent with marked, widespread virus replication. Viral titers were approximately 3,000 times greater in blood and 30,000 to 50,000 times greater in other tissues (eg, pancreas and small intestine) in American crows versus fish crows. Histologic lesion patterns and antigen deposition supported the differing clinical outcomes, with greater severity and distribution of lesions and WNV antigen in American crows. Both crow species had multiorgan necrosis and inflammation, although lesions were more frequent, severe, and widespread in American crows, in which the most commonly affected tissues were small intestine, spleen, and liver. American crows also had inflammation of vessels and nerves in multiple tissues, including heart, kidney, and the gastrointestinal tract. WNV antigen was most commonly observed within monocytes, macrophages, and other cells of the reticuloendothelial system of affected tissues. Collectively, the data support that WNV-infected American crows experience uncontrolled systemic infection leading to multiorgan failure and rapid death.


Subject(s)
Antibodies, Viral/blood , Antigens, Viral/blood , Bird Diseases/pathology , Crows/virology , West Nile Fever/veterinary , West Nile virus/immunology , Animals , Animals, Wild , Bird Diseases/mortality , Bird Diseases/virology , Electrocardiography/veterinary , Feces/virology , Species Specificity , Viremia/veterinary , Virus Replication , West Nile Fever/mortality , West Nile Fever/pathology , West Nile Fever/virology , West Nile virus/isolation & purification , West Nile virus/physiology
16.
Vet Pathol ; 48(3): 706-12, 2011 May.
Article in English | MEDLINE | ID: mdl-20926735

ABSTRACT

This article describes 10 cases of paranasal sinus masses in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Among 21 bighorns that were examined from 11 herds in Colorado, 10 individuals (48%) from 4 herds (36%) had masses arising from the paranasal sinuses. Affected animals included 9 of 17 females (53%) and 1 of 4 males (25%), ranging in age from approximately 2 years to greater than 10 years. Defining gross features of these masses included unilateral or bilateral diffuse thickening of the respiratory lining of the maxillary and/or frontal sinuses, with abundant seromucinous exudate in the affected sinus cavities. Defining histologic features of these masses included chronic inflammation and proliferation of mesenchymal and epithelial cells of the mucosa and submucosa. Epithelial changes included hyperplasia of mucosal epithelium, hyperplasia of submucosal glands and ducts, and neoplasia (adenocarcinoma). Mesenchymal changes included submucosal myxedema, submucosal fibroplasia/fibrosis, bone destruction, and neoplasia (myxomatous fibroma). Specific immunohistochemistry and polymerase chain reaction for Jaagsiekte sheep retrovirus and enzootic nasal tumor virus were performed with negative results.


Subject(s)
Paranasal Sinus Neoplasms/veterinary , Paranasal Sinuses/pathology , Sheep, Bighorn , Sinusitis/veterinary , Animals , Female , Male , Paranasal Sinus Neoplasms/pathology , Sinusitis/pathology
17.
Vet Pathol ; 47(3): 536-46, 2010 May.
Article in English | MEDLINE | ID: mdl-20382822

ABSTRACT

Eyes and nuclei of the visual pathways in the brain were examined in 30 Rocky Mountain elk (Cervus elaphus nelsoni) representing 3 genotypes of the prion protein gene PRNP (codon 132: MM, ML, or LL). Tissues were examined for the presence of the abnormal isoform of the prion protein associated with chronic wasting disease (PrP(CWD)). Nuclei and axonal tracts from a single section of brain stem at the level of the dorsal motor nucleus of the vagus nerve were scored for intensity and distribution of PrP(CWD) immunoreactivity and degree of spongiform degeneration. This obex scoring ranged from 0 (elk with no PrP(CWD) in the brain stem) to 10 (representing elk in terminal stage of disease). PrP(CWD) was detected in the retina of 16 of 18 (89%) elk with an obex score of > 7. PrP(CWD) was not detected in the retina of the 3 chronic wasting disease-negative elk and 9 elk with an obex score of < 6. PrP(CWD) was found in the nuclei of the visual pathways in the brain before it was found in the retina. Within the retina, PrP(CWD) was first found in the inner plexiform layer, followed by the outer plexiform layer. Intracytoplasmic accumulation of PrP(CWD) was found in a few neurons in the ganglion cell layer in the PRNP 132ML elk but was a prominent feature in the PRNP 132LL elk. Small aggregates of PrP(CWD) were present on the inner surface of the outer limiting membrane in PRNP 132LL elk but not in PRNP 132MM or 132ML elk. This study demonstrates PrP(CWD) accumulation in nuclei of the visual pathways of the brain, followed by PrP(CWD) in the retina.


Subject(s)
Brain/metabolism , Deer/metabolism , Prions/metabolism , Retina/metabolism , Visual Pathways/metabolism , Wasting Disease, Chronic/metabolism , Animals , Brain/pathology , Deer/genetics , Epitope Mapping , Female , Prions/chemistry , Protein Isoforms/metabolism , Retina/pathology , Wasting Disease, Chronic/pathology
18.
Vet Pathol ; 47(1): 34-9, 2010 Jan.
Article in English | MEDLINE | ID: mdl-20080482

ABSTRACT

Interest in the epidemiology of emerging diseases of humans and livestock as they relate to wildlife has increased greatly over the past several decades. Many factors, most anthropogenic, have facilitated the emergence of diseases from wildlife. Some livestock diseases have "spilled over" to wildlife and then "spilled back" to livestock. When a population is exposed to an infectious agent, depending on an interaction of factors involving the host, agent, and environment, the population may be resistant to infection or may become a dead-end host, a spillover host, or a maintenance host. Each exposure is unique; the same species of host and agent may respond differently in different situations. Management actions that affect the environment and behavior of a potential host animal may allow the emergence of a new or as yet undetected disease. There are many barriers in preventing, detecting, monitoring and managing wildlife diseases. These may include political and legal hurdles, lack of knowledge about many diseases of wildlife, the absence of basic data on wildlife populations, difficulties with surveillance, and logistical constraints. Increasing interaction between wildlife and humans or domestic animals may lead to disease emergence and require innovative methods and strategies for disease surveillance and management in wildlife.


Subject(s)
Animals, Wild , Communicable Diseases, Emerging/etiology , Disease Reservoirs , Animal Diseases/etiology , Animal Diseases/transmission , Animals , Animals, Domestic , Communicable Diseases, Emerging/prevention & control , Communicable Diseases, Emerging/transmission , Humans , Population Surveillance , Zoonoses/etiology , Zoonoses/transmission
19.
Vet Pathol ; 45(6): 901-4, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18984793

ABSTRACT

A 13-year-old, spayed, female Australian Cattle Dog had at least a 10-year history of numerous subcutaneous nodules for which fine-needle aspiration and cytologic evaluation were nondiagnostic. Abdominal ultrasound 3.5 months before necropsy detected a small left kidney but no cysts or neoplasms. At gross necropsy, innumerable, firm, round to oval, white, 0.25 to 2 cm masses were detected throughout the subcutaneous tissues of the axial and appendicular skeleton, epimysium of numerous muscles, and parietal peritoneum of the lateral abdominal body wall. The left kidney was approximately half the size of the right, and there was severe bilateral renal medullary (papillary) necrosis. Histologically, the subcutaneous nodules were well-demarcated masses of mature, hypocellular collagen that were consistent with previous reports of nodular dermatofibrosis and renal cystadenomas or cystadenocarcinomas. In addition to diffuse acute medullary necrosis, both kidneys were affected by severe chronic lymphoplasmacytic interstitial nephritis. This is the first known report of nodular dermatofibrosis in a dog without renal cysts, cystadenoma, or cystadenocarcinoma.


Subject(s)
Dog Diseases/pathology , Skin Diseases/veterinary , Animals , Dog Diseases/diagnosis , Dogs , Female , Kidney Neoplasms/veterinary , Skin Diseases/diagnosis , Skin Diseases/pathology
20.
Parasitol Res ; 103(5): 1025-9, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18587686

ABSTRACT

Intestines of dead northern fur seals (Callorhinus ursinus) on St. Paul Island (SPI), Alaska were inspected for specific internal parasites (hookworms and acanthocephalans) in July and August, 2007. Pups (n=64) were examined for adult hookworms (Uncinaria lucasi) and four (6.25%) were infected. The number of specimens per infected pup was 1, 2, 2, or 408. Low prevalence was similar to that determined in the last investigation (2001) in dead fur seal pups on SPI by two of the present authors (Lyons and Spraker). Subadult males (SAMS-3-4 years old, n=115) were examined for acanthocephalans and 25 (21.7.0%) were infected. Adult Corynosoma (C. obtuscens, C. strumosum, and C. validum) (n=56) and immature Bolbosoma spp. (n=4) were found. Apparently, this is a new host record for C. obtuscens and C. validum. Notes were made on finding tapeworms. in 114 of the 115 SAMs. Examination of some specimens revealed scolices characteristic of Diphyllobothrium spp.


Subject(s)
Acanthocephala/isolation & purification , Ancylostomatoidea/isolation & purification , Fur Seals/parasitology , Helminthiasis, Animal/epidemiology , Acanthocephala/ultrastructure , Alaska/epidemiology , Animals , Female , Male , Prevalence
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