bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Reproduction of Bovine Fetal Neospora Infection and Death with a Bovine Neospora Isolate
Authors: Barr Bradd C. , Rowe Joan D. , Sverlow Karen W. , BonDurant Robert H. , Ardans Alex A. , Oliver Michael N. , Conrad Patricia A.
Published: May 2011

Studies were conducted to determine the pathogenic potential of the recently isolated bovine Neospora protozoa (BPA-1) for the bovine fetus. Cows chosen for study had Neospora titers < 160 using an indirect immunofluorescent antibody (IFA) test. Four experimental groups were studied. In group 1, 2 fetuses were inoculated in utero at 118 days gestation with culture-derived Neospora tachyzoites. A pregnant control cow was housed in the same pen, observed daily and screened serologically for evidence of exposure to Neospora. In group 2, 2 cows were infected with Neospora tachyzoites at 138 or 161 days gestation, and 1 control cow was given uninfected cell culture suspension simultaneously at 154 days gestation. Groups 3 (85 days gestation) and 4 (120 days gestation) each consisted of 2 cows infected with Neospora tachyzoites and 1 control cow given uninfected material at the same stage of gestation. Dead fetuses were surgically removed from the infected cows in group 1 on postinfection day (PID) 17. The histopathology was compatible with protozoal fetal infection, and protozoa were identified by immunohistochemistry. Viable fetuses were removed surgically from cows in group 2 on PID 28-30. The histopathology was compatible with protozoal fetal infection, protozoa were identified by immunoperoxidase techniques, and Neospora tachyzoites were reisolated in vitro from tissues of the 2 infected fetuses. In groups 3 and 4, the control fetus and 1 infected fetus were removed surgically between PID 26 and PID 33. The remaining infected cows were observed until fetal death or abortion occurred. In group 3, the fetus that was surgically removed from 1 infected cow had no pathologic abnormalities, and parasites were not found (PID 26). The second fetus in group 3 died in utero, and expulsion of a mummified fetus was induced on PID 67. Brain histopathology was compatible with protozoal infection, and parasites were identified by immunoperoxidase techniques. The fetus that was surgically removed (PID 32) from 1 infected cow in group 4 had lesions compatible with protozoal infection, and Neospora tachyzoites were reisolated in vitro from fetal tissues. The second infected cow in group 4 produced a full-term live calf that had a precolostral Neospora titer of 20,480. Clinically, this calf had depressed conscious proprioception in all limbs. Very mild lesions were found in the central nervous system, but protozoa were not found in the tissues. The results demonstrate that the bovine Neospora protozoa can be transplacentally transmitted, resulting in fetal infection and death, and mimics the naturally occurring fetal disease.
Ultrastrutitural Pathology of an Inherited Lower Motor Neuron Disease of Pigs
Authors: O'Toole Donal , Wells Gerald , Ingram James , Cooley William , Hawkins Stephan
Published: May 2011

The ultrastructural features of a recently described inherited lower motor neuron disease were studied in 5 affected pigs. Clinical signs comprised progressive ataxia and paresis of variable severity. Affected pigs, 6, 7, 15, 15, and 19 weeks of age, and 2 unrelated healthy pigs, 9 and 15 weeks of age, were anesthetized and their tissues were fixed by whole body perfusion with mixed aldehydes. From 1 or more affected pigs, samples of cervical and lumbar spinal ventral horn, lateral and ventral spinal columns, dorsal and ventral lumbar spinal nerve roots, 2 peripheral nerves (Nn. phrenicus and fibularis communis), and 2 skeletal muscles (Mm. diaphragma and tibialis cranialis) were examined ultrastructurally. There was widespread degeneration of myelinated axons in peripheral nerves and in lateral and ventral columns of lumbar and cervical segments of spinal cord. Axonal degeneration was present in ventral spinal nerve roots and was absent in dorsal spinal nerve roots sampled at the same lumbar levels. Unmyelinated axons in peripheral nerves and spinal nerve roots were unaffected. In 4 of 5 affected pigs, there were atrophic alpha motor neurons in cervical spinal cord that contained dense, round osmiophilic perikaryal inclusions up to 4 μm in diameter and round swollen mitochondria. Axonal regeneration was present in N. phrenicus of the 19-week-old affected pig that had clinical signs of longest duration (10 weeks). There was no morphologic evidence of axonal degeneration or spinal neuronal atrophy in either control pig. The ultrastructural features of this motor neuron disease distinguish it from other reported progressive spinal neuropathies of pigs.
Diagnosis of Polyomavirus-Induced Hepatic Necrosis in Psittacine Birds Using DNA Probes
Authors: Garcia AnaPatricia , Latimer Kenneth S. , Niagro Frank D. , Ritchie Branson W. , Campagnoli Raymond P.
Published: May 2011

Liver sections from 32 psittacine birds with multifocal to coalescing hepatocellular necrosis were examined to determine the cause of disease. Avian polyomavirus (APV) infection (19 of 32 birds), bacterial hepatitis (5 of 32 birds), and chlamydiosis (3 of 32 birds) were major causes of hepatic disease. The presence of APV inclusions or nucleic acid was demonstrated using hematoxylin and eosin (HE) staining, DNA in situ hybridization, and DNA amplification with Southern blotting. Amphophilic intranuclear inclusions, suggestive of APV infection, were observed in HE-stained liver sections from 5 of 32 birds. Hepatocellular karyomegaly was present in liver tissues from 10 birds (5 birds with typical APV inclusions and 5 birds without discernable inclusions). DNA in situ hybridization recognized intranuclear APV nucleic acid in liver sections of 18 of 32 birds. DNA amplification with Southern or dot blots also identified APV nucleic acid in processed, paraffin-embedded livers of 18 of 32 birds. This study demonstrates that acute APV infection is a frequent cause of multifocal to coalescing hepatocellular necrosis in psittacine birds. Furthermore, APV infection is best diagnosed using DNA probes, especially when typical intranuclear inclusions are not observed microscopically.
Lesions Caused by Natural Infection with Streptococcus Suis Type 9 in Weaned Pigs
Authors: Vasconcelos Daphne , Middleton Dorothy M. , Chirino-Trejo J. Manuel
Published: May 2011

In this paper we report on the spectrum and frequency of lesions observed in a prospective study of naturally occurring infections with Streptococcus suis type 9 (SS-9) in weaned pigs. SS-9 produced arthritis, meningitis, interstitial pneumonia, and endocarditis in 100%, 91%, 73%, and 42%, respectively, of pigs dying from the disease. The lesions were similar to those caused by S. suis type 2 (SS-2), however, SS-9 produced a different frequency of lesions. In SS-2 infections, bronchopneumonia is the most commonly observed lesion; meningitis, arthritis, and endocarditis are less frequently observed. Thus, SS-9 produced a different distribution of lesions from that reported for SS-2. Possible explanations for the differences found are discussed.
Fecal Shedding of Clostridium Difficile in Dogs: A Period Prevalence Survey in a Veterinary Medical Teaching Hospital
Authors: Struble Andrea L. , Tang Yajarayma J. , Kass Philip H. , Gumerlock Paul H. , Madewell Bruce R. , Silva Joseph
Published: May 2011

The goal of this study was to determine the fecal prevalence of Clostridium difficile in dogs who were patients at a veterinary medical teaching hospital. Stool specimens collected from 152 dogs (in- and outpatients) were analyzed for the presence of C. difficile. An additional 42 stool specimens were collected and examined from dogs recently housed at local animal shelters. Following culture on selective medium, C. difficile was identified by a latex agglutination test, and the presence of the toxin A and B genes was determined individually by polymerase chain reaction. Clostridium difficile was isolated from the feces of 28 of the veterinary hospital patients (18.4%); isolates from 14 of these patients (50.0%) were toxigenic. Diarrhea was a clinical finding in 5 (35.7%) of the dogs carrying toxigenic isolates of C. difficile, whereas diarrhea was noted in only 2 of 14 dogs (14.3%) shedding nontoxigenic isolates. Three of 14 dogs (2 1.4%) shedding toxigenic isolates of C. difficile were receiving antibiotics at the time of stool collection, whereas 5 of 14 dogs (37.5%) shedding non-toxigenic strains of C. difficile were receiving antibiotics. The carriage rate of C. difficile was significantly higher for animals categorized as inpatients of the veterinary hospital. The carriage rate also provided evidence for an increased risk for fecal shedding with increasing age. Clostridium difficile was not isolated from any of the 42 dogs recently housed at local animal shelters. This study confirms the presence of toxigenic C. difficile in dogs at a veterinary teaching hospital. Additional studies will be required to determine whether prior antibiotic treatment increases the frequency of C. difficile fecal shedding from dogs and whether colonized dogs are a risk for transmission of the organism to susceptible human populations.
Improved Extraction and HPLC Methods for Ergovaline from Plant Material and Rumen Fluid
Authors: Craig A. Morrie , Bilich Dan , Hovermale Jeannette T. , Welty Ronald E.
Published: May 2011

Ergovaline, the main ergopeptine alkaloid produced in tall fescue infected with Acremonium coenophialum, is known to cause tall fescue toxicosis. Current methods in use for quantifying ergovaline in plant material have several disadvantages, including large solvent volumes and long analysis time. We report here improvements in extraction and cleanup and the high-pressure liquid chromatographic methods. Our improvements include a 24-hour extraction time, the use of smaller solvent volumes during sample preparation, and fast analysis on the polymeric reverse-phase column. In addition to allowing the analysis of large batches to assist practitioners in the accurate diagnosis of fescue toxicosis, our method is also easily modified for other matrices, such as rumen fluid.
Serum Immune Responses to the Proteins of Porcine Reproductive and Respiratory Syndrome (PRRS) Virus
Authors: Nelson Eric A. , Christopher-Hennings Jane , Benfield David A.
Published: May 2011

The antibody responses of pigs to porcine reproductive and respiratory syndrome virus (isolate VR-2332) were evaluated by indirect immunofluorescence, virus neutralization, and immunoblotting. All pigs in each group were positive by indirect immunofluorescence 14-21 days postexposure (DPE), and antibodies to specific viral proteins (15, 19 or 26 kD) were initially demonstrated by immunoblotting at 7–21 days DPE. Neutralizing antibodies were detected in only 2 pigs that were inoculated intranasally and given additional parenteral injections with adjuvant. These antibodies appeared much later, 51–70 DPE, than did antibodies detected by indirect immunofluorescence. The titer of the neutralizing antibodies increased until 127 DPE, after which the titers decreased, and 1 animal became seronegative for neutralizing antibody by 262 DPE.
Evaluation of Rotavirus Infection and Diarrhea in Iowa Commercial Pigs Based on an Epidemiologic Study of a Population Represented by Diagnostic Laboratory Cases
Authors: Will Loren A. , Paul Prem S. , Proescholdt Terry A. , Aktar Syeda Naheed , Flaming Kevan P. , Janke Bruce H. , Sacks Jerome , Lyoo Young Soo , Hill Howard T. , Hoffman Lorraine J. , Wu Lie-Ling
Published: May 2011

Group A, B, and C rotaviruses were identified in 9% (96/1,048) of pig fecal specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory during 1987 and 1988. Six of the rotaviruses were group B, 5 were group C, and the remaining 89% were group A. Of the rotavirus cases with more than 1 serotype, 5 were multiple group A serotypes, 1 involved a group A and B serotype, and 1 included 2 group C serotypes. A retrospective epidemiologic evaluation of pig diarrhea in herds of origin was done using data obtained from the accession records of the rotavirus and 88 matched nonrotavirus pig diarrhea control cases. Herds from which rotavirus cases were derived experienced lower morbidity, mortality, and case fatality rates than matched control herds. The incidence of diarrhea decreased rapidly among all pigs from birth to 3 weeks of age. The peak incidence for piglet diarrhea occurred in February, and a moderate rise occurred in August-September. Definitive evidence for transmissible gastroenteritis virus was found in 12% of nonrotavirus cases but none of the rotavirus cases in which it was sought. Other pathogenic microorganisms were identified less frequently and inconsistently.
Molecular Fingerprinting of Pasteurella Multocida Associated with Progressive Atrophic Rhinitis in Swine Herds
Authors: Gardner Ian A. , Kasten Rick , Eamens Graeme J. , Snipes Kurt P. , Anderson Randall J.
Published: May 2011

Ninety-six nasal isolates of Pasteurella multocida from swine herds with progressive atrophic rhinitis were characterized by restriction endonuclease analysis (REA) of whole-cell DNA, ribotyping, and plasmid analysis. For REA, bacterial DNA was digested with SmaI and electrophoresed in 0.7% agarose, and fragments were visualized with UV light. For ribotyping, EcoRI-digested and electrophoresed restriction fragments of whole-cell DNA were transferred to nitrocellulose membranes, hybridized with γ-32P-labeled Escherichia coli ribosomal RNA, and visualized by autoradiography. Phenotypes of isolates were toxigenic capsular type D ( n = 51), nontoxigenic type D ( n = 28), nontoxigenic type A ( n = 16), and toxigenic type A ( n = 1). Plasmids of various sizes were evident in 92.2% and 17.9% of toxigenic and nontoxigenic D strains, respectively, but were absent from all type A strains. Among the 4 phenotypes, there were 17 REA profiles and 6 ribotypes. For 3 of 17 REA patterns, multiple ribotypes were evident, and several REA types were evident in 5 of 6 ribotypes. Thirty-seven isolates of toxigenic capsular type D from Australian herds were either SmaI type B or C and ribotype 2, whereas 14 toxigenic D isolates from the USA and other countries were more heterogeneous (7 REA types and 6 ribotypes). The fingerprinting results provided evidence in support of the hypothesis of a single source infection in Australia associated with the introduction of breeding pigs from overseas.
Characteristics of a Brucella Species from a Bottlenose Dolphin (Tursiops Truncatus)
Authors: Ewalt Darla R. , Payeur Janet B. , Martin Barbara M. , Cummins Donna R. , Miller W. George
Published: May 2011

A culture isolated from an aborted fetus of a bottlenose dolphin ( Tursiops truncatus) was characterized. The isolate was a gram-negative coccobacillus, and the colonial morphology was typical of a smooth Brucella. The isolate was positive for catalase, oxidase, nitrate reduction, and urease. Hydrogen sulfide was not produced. It grew in air at 37 C but required 72 hours for good growth. There was growth on media containing basic fuchsin, thionin, thionin blue, penicillin, and erythritol. The M antigen was dominant, and the isolate was lysed by 4 of 10 brucellaphages tested. The oxidative metabolic profile of the isolate was similar to that for B. abortus but differed in utilization of L-asparagine, L-glutamic acid, and DL-citrulline. Whole-cell lysates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein profiles were markedly different from the protein profiles of reference strains of Brucella species. Biochemical and oxidative metabolism profiles indicated that the isolate belongs in the genus Brucella but did not match the profiles of any established species or biovars. This isolate may be an atypical strain of a recognized Brucella species or a new biovar or species of Brucella.
Multifocal Subacute Necrotizing Encephalomyelopathy in Simmental Calves
Authors: Steffen D. J. , Vestweber J. G. , Cash W. , El-Hamidi M. , Leipold H. W.
Published: May 2011

In 24 cases of multifocal necrotizing encephalopathy (MNE) in Simmental and Simmental-cross cattle, clinical features varied, consisting of mild rear limb ataxia, caudal paresis, and, less often, sudden death. Bilateral and symmetric malacic lesions were present in the brain stem (olivary nucleus) of all affected calves. Foci of malacia affecting thoracic spinal cord and additional brain stem sites were common. Neuronal cell bodies and hypertrophied capillaries were present within malacic foci. Rarefaction of neuropil, progressing to complete parenchymal loss, characterized advanced lesions. Pathologic features were similar to those of Leigh syndrome in humans, and a similar defect in aerobic metabolism is hypothesized. Occurrence of the syndrome within 1 breed over a wide geographic area suggests that hereditary factors contribute to development of MNE.
Serum α-Mannosidase Activity and the Clinicopathologic Alterations of Locoweed (Astragalus Mollissimus) Intoxication in Range Cattle
Authors: Stegelmeier Bryan L. , Ralphs Michael H. , Gardner Dale R. , Molyneux Russell J. , Jame Lynn F.
Published: May 2011

Subclinical intoxication of livestock with Astragalus and Oxytropis species (locoweeds) results in decreased animal feed conversion, reduced weight gains, and reproductive failure. Sensitive diagnostic methods to definitively diagnose and monitor intoxication are needed to minimize these losses and better manage locoweed-infested pastures and rangelands. Sera from cattle grazing locoweed were evaluated for α-mannosidase activity, serum biochemical values, electrolytes, and thyroid hormone concentrations. As the cows began to ingest locoweed, the mean serum α-mannosidase activities dropped significantly (400.0 μM to 72.5 μM). Changes in other serum chemistry values were less specific; however, individual animals (generally those ingesting more locoweed) had elevated levels of alkaline phosphatase (ALP), aspartate aminotransferase, and lactate dehydrogenase, with decreased serum total protein (5.8 ± 0.8 g/dl) and albumin (2.3 ± 0.3 g/dl). Mean serum thyroid concentrations (both T4 and T3) were lower in animals that were ingesting locoweed. The calculated swainsonine dose correlated statistically with serum α-mannosidase activity, ALP, albumin, C, CO2, and thyroid hormone T3. This correlation suggests that serum α-mannosidase activity along with potential changes in ALP, albumin, and thyroid hormone concentrations is a sensitive indicator of locoweed exposure and intoxication. These parameters may also be useful for monitoring intoxication and allowing subclinically affected cattle to be removed from infested areas before irreversible damage occurs.
A Comparison of Three Avidin-Biotin Complex Immunoenzyme Systems for Detection of African Swine Fever Virus Antigen in Paraffin-Embedded Tissues
Authors: Gregg Douglas A. , Mebus Charles A. , Schlafer Donald H.
Published: May 2011

The sensitivity and specificity of 3 avidin-biotin complex (ABC) immunostaining systems were compared on paraffin-embedded tissues from African swine fever virus (ASFV)-infected pigs. Results were also compared with immunofluorescent detection on cryosections of the same tissue for optimal detection of ASFV antigen. The ABC-alkaline phosphatase (ABC-AP) and ABC-peroxidase (ABC-PO) systems were at least as sensitive as direct fluorescent antibody (FA) and 10-fold more sensitive than the ABC-glucose oxidase system. Three ABC-AP and 2 ABC-PO chromagens with different counterstains were compared. In addition, 2 fixatives, 2 biotinylation procedures, 7 endogenous peroxidase blocking regimes, 6 tissue adhesives, and 3 mounting media were compared. The ABC-AP system with a red chromagen and hematoxylin counterstaining was preferred and most closely approximated routinely stained pathologic sections. Fixation in paraformaldehydelysine-periodate fixative preserved ASFV antigen for research studies for at least 3 years. Formalin-fixed tissues retained some staining for up to 10 years.
Immunohistochemical Detection of Tritrichomonas Foetus in Formalin-Fixed, Paraffin-Embedded Sections of Bovine Placenta and Fetal Lung
Authors: Rhyan Jack C. , Wilson Kristin L. , Burgess Donald E. , Stackhouse Larry L. , Quinn William J.
Published: May 2011

An immunohistochemical technique using a monoclonal antibody was evaluated as a diagnostic tool to specifically label Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of placenta and fetal lung from bovine abortions. Trichomonads were demonstrated in tissues from each of 12 abortions due to T. foetus and none of 15 abortions due to other or unidentified causes. Moderate to marked background staining occurred only in severely autolyzed tissues from T. foetus-infected fetuses. The antibody faintly labeled 1 of 3 other species of trichomonads (Trichomonas gallinae) but did not label other protozoa, bacteria, or fungi tested.
Chronic Generalized Obliterative Arteriopathy in Cattle: A Sequel to Sheep-Associated Malignant Catarrhal Fever
Authors: O'Toole Donal , Li Hong , Roberts Steven , Rovnak Joel , DeMartini James , Cavender Jackie , Williams Bill , Crawford Tim
Published: May 2011

Malignant catarrhal fever (MCF) in cattle is generally associated with a short clinical course and a high case fatality rate (90–95%). The lesions in cattle that survive acute MCF for a prolonged period or appear to recover have not been documented. In a naturally occurring outbreak of MCF in a herd of beef cattle in Wyoming, 7 of 84 yearling heifers (8.3% of replacement herd) and 2 of 230 cows (0.9% of cow herd) developed clinical signs of pyrexia, mucopurulent discharge, bilateral keratitis, and weight loss following contact with ewes that had lambed 34–62 days earlier. Six of 9 affected cattle were examined postmortem following clinical signs (CS) that developed 2–150 days earlier. Three cattle with CS for ≤39 days had lesions of regional lymphadenopathy and widespread severe segmental lymphoid arteritis-phlebitis that were typical of acute MCF, and proliferative intimal lesions were present in a small proportion of arteries at days 20 and 39 of CS. By contrast, 3 cattle that survived to 90, 105, and 150 days after clinical onset had distinctive arterial lesions in multiple organs, characterized by proliferative concentric fibrointimal plaques, disrupted inner elastic lamina, focally atrophic tunica media, and vasculitis of variable severity. Immunohistochemical and ultrastructural examination of intimal plaques identified the predominant cellular component to be smooth muscle cells with a contractile phenotype. No viral structures were seen. Serologic studies, using a competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA) that detects antibody to an epitope broadly conserved among isolates of the MCF virus, found that 2 chronically affected cattle were serologically positive between days 42 and 100 of CS, with seroconversion in 1 animal between days 52 and 73 of CS. Seroprevalence was 7.9% in the 76 remaining healthy animals of the replacement heifer herd and 40% (75% in adult sheep and 4% in lambs) in the in-contact sheep flock 77 days after onset of CS in the index case. This episode suggests that, in addition to the common and well recognized acute form of MCF in cattle, this viral infection encompasses a disease spectrum that includes chronic disease and partial to “complete” clinical recovery, and in recovered animals chronic obliterative arteriopathy is the preeminent lesion. The MCF CI-ELISA may be helpful in identifying such cattle and in epidemiologic studies of MCF outbreaks.
Spontaneous Glomerulonephritis in Swine
Authors: Bourgault Andrée , Drolet Richard
Published: May 2011

In this investigation, 32 cases of naturally occurring glomerulonephritis in swine were studied retrospectively (1973–1993). Almost all affected pigs were crossbred and more than half were growing pigs. Nearly two thirds of the pigs showed gross renal lesions characterized by bilateral kidney enlargement, palor, edema, and/or cortical petechiation. The most commonly encountered extrarenal lesions were serous bodily effusions and gastric ulcers. The renal disease was considered the primary cause of death in 11 pigs. Histologically, the renal lesions in all pigs were characterized by a generalized and global proliferative glomerulonephritis. Mesangioproliferative glomerulonephritis was diagnosed in 2 pigs, whereas the glomerular lesions found in the other pigs (30/32) were characterized by a proliferative and exudative glomerulonephritis frequently associated with crescent formation. In all pigs, there was histologic evidence of proteinuria. A focal necrotizing vasculitis was found in the kidneys of 7 pigs. Although probably of immune origin, the precise etiopathogenesis of the porcine glomerulonephritis described herein after remains unknown.
Comparison of Argyrophilic Nucleolar Organizer Regions (AgNORs) and Mitotic Index in Distinguishing Benign from Malignant Canine Smooth Muscle Tumors and in Separating Inflammatory Hyperplasia from Neoplastic Lesions of the Urinary Bladder Mucosa
Authors: Johnson Gayle C. , Miller Margaret A. , Ramos-Vara Jose A.
Published: May 2011

Staining for argyrophilic nucleolar organizer regions (AgNORs) has proven useful in differentiating recurrent or malignant neoplasms from less aggressive or benign ones. We applied this stain to benign and malignant smooth muscle tumors and to hyperplastic and carcinomatous lesions in the urinary bladder of dogs in an effort to determine its utility in diagnostic situations. The stain was simply performed, and the results were repeatable for different staining intervals and between staining batches. For smooth muscle tumors, enumeration of AgNORs in 100 nuclei was about as efficient as mitotic index in correctly categorizing histologically benign and malignant neoplasms. The mean number of AgNORs/100 nuclei for leiomyomas was significantly less than that obtained for leiomyosarcomas and significantly greater than that obtained for normal smooth muscle. Counts for smooth muscle tumors correlated with the mitotic indexes. Counts by an individual observer were repeated without introducing significant variation, but there was variability between observers, particularly in AgNOR counts for leiomyosarcomas. AgNORs were not useful in separating hyperplastic or polypoid cystitis from transitional cell carcinoma, misclassifying both. Mean AgNOR counts for these 2 conditions did not differ at the 5% level of significance; mitotic index was more efficient at separating the 2 conditions. There was no correlation between mitotic index and AgNOR in urinary tract mucosal specimens. This easily prepared stain may be useful in separating benign and malignant smooth muscle tumors, although AgNORs were less contributory to diagnosing mucosal lesions of the urinary bladder of dogs.
Analysis of the Serologic Relationship among San Miguel Sea Lion Virus and Vesicular Exanthema of Swine Virus Isolates. Application of the Western Blot Assay for Detection of Antibodies in Swine Sera to these Virus Types
Authors: Seal Bruce S. , House James A. , Whetstone Cecelia A. , Neill John D.
Published: May 2011

Caliciviruses are positive-sense single-stranded RNA viruses with a single capsid protein. The serotypes of the marine mammal calicivirus, San Miguel sea lion virus (SMSV), are antigenically related to vesicular exanthema of swine virus (VESV) and are potentially hazardous to swine. Western blot assays using purified SMSV serotypes 1 and 4 were used to further examine the serologic relationship among SMSV and VESV isolates. With the exception of SMSV 8 and SMSV 12, rabbit polyclonal antisera generated against all the available SMSV and VESV isolates reacted positively, as assessed by western blot, with purified capsid protein from SMSV 1 and SMSV 4. Consequently, the SMSV 8 and SMSV 12 virus isolates may not be members of the SMSV/VESV calicivirus group. Using antisera from pigs experimentally inoculated with SMSV and VESV as positive controls, a western blot assay for these virus types was utilized to check for the presence of antibodies to caliciviruses in swine sera. Sera from colostrum-deprived gnotobiotic pigs were used as a negative control in all experiments. Examination of sera from domestic and feral swine collected in Iowa, California, and Florida was completed using this technique. The presence of antibodies to these virus types was not detected in any of the porcine sera tested.
Neuroaxonal Degeneration in Sheep Grazing Sorghum Pastures
Authors: Bradley Gregory A. , Metcalf H. Carter , Reggiardo Carlos , Noon Ted H. , Bicknell Edward J. , Lozano-Alarcon Fernando , Reed Raymond E. , Riggs Michael W.
Published: May 2011

During the fall of 1992, 250 (10%) of 2,500 Rambouilet cross feeder lambs grazing Sorghum bicolor developed neurologic signs including weakness, ataxia, head shaking, knuckling of the fetlocks, inability to rise, and opisthotonos. One hundred fifteen (46%) of the affected lambs died. Twenty of the surviving lambs exhibited residual neurologic signs of ataxia when stressed. At the same time, 275 (25%) of 1,100 ewes grazing a nearby sudex pasture ( S. sudanese × S. bicolor) gave birth to lambs that were weak and unable to rise. Newborn lambs exhibited extensor rigidity and opisthotonos when assisted to a standing position. The dystocias that occurred were due to lambs with contracted limbs (arthrogryposis). All affected lambs died or were euthanized. Histologic examination of the brains of 3 feeder lambs and 9 newborn lambs revealed similar microscopic lesions. The predominant change was the presence of focal axonal enlargements (spheroids) in the proximal segments of axons, which were restricted to the nuclei of the medulla, cerebellum, and midbrain. In addition, the spinal cord contained spheroids in the ventral horn gray matter of the 6 newborns examined. Ultrastructurally, the spheroids were composed of aggregates of neurofilaments, mitochondria, vesicular bodies, and dense bodies bounded by a thin myelin sheath. There was mild gliosis in the more severely affected animals of both groups. There was minimal Wallerian degeneration in the white matter adjacent to affected nuclei in the brain and the ventromedial and dorsolateral funiculi of the spinal cord. This is the first detailed report of Sorghum toxicity in sheep.
Evaluation of Shell Vial Cell Culture Technique for the Detection of Bovine Coronavirus
Authors: Tahir Rafique A. , Pomeroy Kern A. , Goyal Sagar M.
Published: May 2011

The effect of blind passage and centrifugation on the isolation of bovine coronavirus in human rectal tumor cells cultured in shell vials was investigated. A total of 68 fecal samples known to be positive for bovine coronavirus by transmission electron microscopic (TEM) examination were used. The samples were centrifuged onto human rectal tumor cell monolayers and incubated in the presence of trypsin. The growth of bovine coronavirus in infected cells was demonstrated by fluorescent antibody staining, and the extracellular virus was detected and confirmed by hemagglutination and hemagglutination-inhibition tests, respectively. Of the 68 TEM-positive samples, 51 (75%), 58 (85%), and 61 (90%) grew in shell vial cell cultures at first, second, and third passages, respectively. Of the 51 cultures positive on first passage, 19 were examined by TEM; 18 of these were positive for bovine coronavirus. The shell vial technique was also compared with direct detection of bovine coronavirus by staining cryostat sections of infected tissues in a direct fluorescent antibody assay. The results of direct fluorescent antibody assay were available for 54 of the 68 samples, of which 53 (98%) and 43 (80%) were positive by shell vial technique and direct fluorescent antibody assay, respectively. For identification of bovine coronavirus, shell vials using human rectal tumor cells in the presence of trypsin is more sensitive than direct fluorescent antibody assay but is relatively less sensitive than transmission electron microscopy.
Immunohistochemical and Pathological Study of Mycoplasma Bovis-Associated Lung Abscesses in Calves
Authors: Adegboye David S. , Halbur Patrick G. , Cavanaugh David L. , Werdin Ronald E. , Chase Christopher C. L. , Miskimins Dale W. , Rosenbusch Ricardo F.
Published: May 2011

Out of 45 cases of fatal chronic pneumonia in calves examined for Mycoplasma bovis infection from February to July 1994, 11 cases with pulmonary abscesses that were culture positive for M. bovis were encountered. The cases were studied in detail using a recently developed monoclonal antibody-based immunoperoxidase technique. Mycoplasma bovis organisms were detected in specific locations at all stages of abscessation observed. In bronchioles or terminal airways within which abscesses developed, M. bovis was located at the epithelial surface and in close association with infiltrating neutrophils and macrophages. Abscessed airways that had lost the epithelium were encapsulated and were seen as coagulative necrotic foci that stained intensely for M. bovis, especially at the periphery. Some foci stained weakly and such might have been resolving lesions. Mycoplasma bovis was also demonstrated at sites of mild mononuclear cell infiltration in the livers and kidneys of 2 calves. The mycoplasma was detected within bile ducts in the liver and in the tubular epithelium of the kidney. Abscesses not staining for M. bovis, presumably caused by other pathogens, were seen concurrently with M. bovis-associated abscesses in some lungs. Thirteen other M. bovis-positive cases showed no abscesses, possibly indicating heterogeneity among M. bovis strains. Three other cases with abscesses were negative for M. bovis by culture and immunoperoxidase staining. The monoclonal antibody-based immunohistochemical technique is efficient for specific detection of M. bovis in cases of enzootic pneumonia of calves with or without abscessation. Mycoplasma bovis is implicated in the pathogenesis of lung abscesses in some calves.
Colonization of the Tracheal Epithelium of Pigs by Filamentous Bacteria Resembling Cilia-Associated Respiratory Bacillus
Authors: Nietfeld Jerome C. , Franklin Craig L. , Riley Lela K. , Zeman David H. , Groff Bruce T.
Published: May 2011

Warthin Starry staining revealed filamentous bacteria colonizing the tracheal epithelium of 41 of 88 (46.6%) pigs submitted for necropsy at 2 midwestem veterinary diagnostic laboratories. The bacteria were interspersed between and oriented parallel to the cilia. In 4 of 4 colonized pig tracheas, filamentous bacteria were demonstrated by transmission electron microscopy. The bacteria were approximately the same length and diameter as cilia, and in areas of heavy colonization the bacteria outnumbered cilia. The filamentous bacteria were similar in location and morphologic characteristics to cilia-associated respiratory (CAR) bacilli of rats, mice, rabbits, and cattle. Results of immunoperoxidase staining and polymerase chain reaction analysis indicated that the pig CAR bacillus is a different bacterium than the rat CAR bacillus. Rat CAR bacillus causes chronic respiratory disease in rats and mice. The association, if any, between pig CAR bacillus and swine respiratory disease is unknown.
Evaluation of an Enzyme-Linked Immunosorbent Assay Licensed by the USDA for Use in Cattle for Diagnosis of Ovine Paratuberculosis
Authors: Dubash Kerman , Shulaw William P. , Beth-Nielsen Steen , Stills Harold F. , Slemons Richard D.
Published: May 2011

A commercially available Mycobacterium phlei-absorbed enzyme-linked immunosorbent assay (ELISA) approved to detect antibodies to Mycobacterium paratuberculosis in cattle was evaluated for its applicability in sheep. The potential for interference with ELISA results from cross-reacting antibodies to Corynebacterium pseudotuberculosis was also investigated. Serum samples were randomly selected from a collection of samples obtained in 1986-1991 from 6 infected and 5 noninfected sheep flocks varying in breed, age, and geographic origin. Tests were performed on sera from 27 paratuberculous sheep, confirmed by histopathology, bacteriologic culture, and/or acid-fast staining of ileal mucosal smears, and on sera from 246 noninfected sheep. The optical density of each sample was expressed as a percentage of the optical density of a known positive sheep serum sample tested on the same plate. These values were log-transformed to achieve normality of distribution, and sensitivity and specificity estimates were calculated based on 2 and 3 standard deviations above the mean of the percent positive value (PPV) of the noninfected sheep. A cutoff value of PPV ≥ 55.74 resulted in an estimated sensitivity of 0.48 and a specificity of 0.95. Sera from 10 noninfected sheep with PPV above the cutoff level of 55.74% were absorbed with heat-treated C. pseudotuberculosis organisms in addition to M. phlei antigens. Sera from 14 ELISA-positive paratuberculous sheep and 23 ELISA-negative noninfected sheep were similarly treated, and results were compared. Absorption with C. pseudotuberculosis resulted in a significant decrease in PPV in all 3 groups of sheep sera, but a greater decrease was observed in the noninfected sheep with PPV above the cutoff level when compared with noninfected sheep with PPV below that level. Results of this study suggest that ELISA may be of value in screening sheep flocks for paratuberculosis, but further experimentation is needed to optimize the sensitivity and specificity of the assay. Exposure to C. pseudotuberculosis may confound results obtained by M. phlei-absorbed ELISA for paratuberculosis.
The Occurrence of Mast Cell Tumors in Young Shar-Peis
Authors: Miller Doris M.
Published: May 2011

During 1991 and 1992, 802 case submissions diagnosed as canine mast cell tumors were submitted to the Athens Veterinary Diagnostic Laboratory. Eighteen of these submissions were from dogs of the Shar-Pei breed. Of these 18 cases, 5 occurred in Shar-Peis less than 2 years of age, 4 of these were poorly differentiated, and 4 out of 5 occurred in the inguinal or preputial area. Three mast cell tumors (grade I) occurred in Boxer/Boxer cross dogs, and 2 tumors (grade II) occurred in Cocker Spaniels younger than 2 years of age. Of the 23,315 histopathology submissions, only 164 were from Shar-Peis and 57 of these dogs were under 2 years of age.
Pathology of Experimentally Induced Chronic Selenosis (Alkali Disease) in Yearling Cattle
Authors: O'Toole Donal , Raisbeck Merl F.
Published: May 2011

Prolonged oral exposure of cattle to elevated dietary selenium (Se) in forage and seleniferous plants in seleniferous areas of the western United States is associated historically with 2 clinical syndromes: alkali disease and “blind staggers.” The potential for Se-induced disease in cattle and other species is considerable in areas with seleniferous shales, Se-accumulating plants, arid climates, and alkaline soils. These 2 Se-associated conditions were defined in the 1930s and 1940s, and the nosology of blind staggers is questionable. Seventeen yearling steers fed 0.15, 0.28, and 0.8 mg Se/kg body weight as selenomethionine or selenite for 120 days were euthanized and examined postmortem. Significant lesions were confined to 4 steers in the medium- and high-dose selenomethionine group and to 1 steer in the high-dose selenite group. Grossly, dystrophic hoof lesions developed in 2 steers, 1 of which had extensive separation of horn from lamellar and coronary epidermis and also lost hair from the tail switch. Histologically, tubules in the stratum medium of hooves from these 5 steers were replaced by islands of parakeratotic cellular debris, separated by more normal hoof matrix. Two of the 5 steers also had hyperplasia, acanthosis, parakeratosis, and disorganized germinal epithelium of varying severity in hoof epithelium, particularly at the tips of epidermal lamellae. These changes may distinguish the hoof lesions of chronic selenosis from those of chronic laminitis in cattle, in which dermal (chorial) changes predominate. In skin from the distal part of the tail of the animal that lost its switch, most follicles were atrophic and devoid of hairshafts and displayed dyskeratosis and mild superficial follicular keratosis. No significant lesions developed in tissues other than integument. Autometallographic staining for catalytic Se bonds in various tissues, including skin, liver, and kidney, revealed no positive staining of hair shafts; the correlation between stain intensity and dose group was poor. These findings indicate that dietary exposure for 4 months to 0.28 and 0.8 mg Se/kg in the form of selenomethionine and to 0.8 mg Se/kg in the form of sodium selenite reproduces in some cattle mild (subclinical) to severe (clinical) forms of alkali disease. No significant neurological, renal, or hepatic lesions developed, supporting the contention that blind staggers is caused by factors other than excessive dietary selenium.
Genome Analysis of North American Small Ruminant Lentiviruses by Polymerase Chain Reaction and Restriction Enzyme Analysis
Authors: Rosati Sergio , Kwang Jimmy , Keen James E.
Published: May 2011

The polymerase chain reaction (PCR) was used to amplify portions of the gag and env structural genes of 8 ovine and 1 caprine lentivirus isolates of North American origin. Three sets of primers were used to amplify p16, p25, and Nî-gp40 gene fragments, and 1 set, annealing highly conserved portions of long terminal repeat (LTR) among small ruminant lentiviruses, was used as a positive control. Variable PCR amplification efficiency was observed. Different stringency conditions of hybridization with specific DNA probes were used to maximize detection of the PCR product. The p25 primers detected all strains, the gp40 primers detected 1 ovine and the caprine strain, and the p16 primers detected only 1 ovine isolate. All strains were detected by LTR primers. Restriction endonuclease analysis of 5 amplified p25 and 2 Nî-gp40 gene fragments revealed extensive heterogeneity among these North American small ruminant lentiviruses.
Persistence of Porcine Reproductive and Respiratory Syndrome Virus in Serum and Semen of Adult Boars
Authors: Christopher-Hennings Jane , Nelson Eric A. , Hines Rebecca J. , Nelson Julie K. , Swenson Sabrina L. , Zimmerman Jeff J. , Chase Christopher C. L. , Yaeger Michael J. , Benfield David A.
Published: May 2011

Four seronegative adult boars were intranasally inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) isolate VR-2332. Serum and semen were collected 2-3 times weekly for over 100 days postinoculation (DPI). Serum samples were assayed for PRRSV by virus isolation (VI) and a polymerase chain reaction (PCR) and screened for antibodies to PRRSV using the indirect fluorescent antibody (IFA) and virus neutralization (VN) tests. Semen was assayed for PRRSV RNA by PCR. Virus or viral RNA was detected in the serum of all boars within 1 DPI by VI and/or PCR. However, VI results indicated that viremia was transient and occurred from 1 to 9 DPI. Viral RNA was detected in serum from 1 to 31 DPI. In the acute stage of the infection, PRRSV RNA was detected in serum by PCR prior to the presence of viral RNA in semen. The PRRSV RNA was detected in semen as early as 3 DPI and persisted for 25 DPI in 2 of the boars and 56 and 92 DPI in the remaining 2 boars. Detection of PRRSV RNA in semen occurred 2-8 and 28-35 days prior to the detection of antibodies by IFA and VN, respectively. PRRSV was isolated from the bulbourethral gland of the boar that shed viral RNA in semen for 92 DPI. These results suggest that PRRSV RNA can be detected by PCR in boar serum and semen, and may persist for variable periods of time. Viremia and the serologic status of the boar are not adequate indicators of when PRRSV or PRRSV RNA is being shed in the semen. Preliminary findings also indicated that neither shipping stress nor reinoculation with homologous PRRSV resulted in viremia or viral RNA shedding in semen.
Detection of Anaplasma Marginale DNA in Bovine Erythrocytes by Slot-Blot and in Situ Hybridization with a PCR-Mediated Digoxigenin-Labeled DNA Probe
Authors: Ge Nie-Lin , Kocan Katherine M. , Murphy George L. , Blouin Edmour F.
Published: May 2011

A 409-base pair (bp) DNA fragment derived from the msp-1β gene of Anaplasma marginale was amplified and simultaneously labeled with digoxigenin-11-dUTP by a polymerase chain reaction (PCR) assay. The resulting digoxigenin-labeled 409-bp PCR product was used as a probe for slot-blot and in situ hybridization to detect A. marginale DNA from experimentally infected bovine erythrocytes. The hybrid formation was detected with alkaline phosphatase-conjugated anti-digoxigenin antibody and substrates 5-bromo-4-chloro-3-indolyl phosphate and nitroblue tetrazolium salt. In slot-blot hybridizations, the probe detected A. marginale DNA from approximately 1,000-10,000 infected erythrocytes in 1.25 ml of whole blood, which is equivalent to a parasitemia level of 0.00001%. The probe proved to be A. marginale-specific when tested with 17 species of microorganisms. The applicability of the probe for diagnosis was tested by screening A. marginale infections in 2 experimentally infected splenectomized cattle before microscopically detectable parasitemias and after acute infection. After inoculation of infected blood, A. marginale infections were detected with the probe 14 days prior to detection in stained smears. Microscopically inapparent parasitemias were also detected with the probe for 2 months after acute disease. When the probe was used for in situ hybridization on methanol-fixed blood smears, probe reaction could be visualized with light microscopy on A. marginale inclusions within infected erythrocytes. The probe reaction was not observed on leukocytes and uninfected erythrocytes from infected blood smears, on erythrocytes from uninfected blood samples, or on samples infected with A. ovis, Babesia bovis, or B. bigemina. This PCR-mediated nonradioactive probe appears to be a sensitive diagnostic test for A. marginale.
Evaluation of a Commercial Enzyme-Linked Immunosorbent Assay for the Diagnosis of Paratuberculosis in Dairy Cattle
Authors: Sweeney Raymond W. , Whitlock Robert H. , Buckley Carol L. , Spencer Pam A.
Published: May 2011

The performance of a commercially available ELISA for detection of antibodies to Mycobacterium paratuberculosis was evaluated using sera from 1,146 cows. Samples were from uninfected cattle, infected subclinical cattle shedding low numbers of organism in feces, subclinical heavy shedders, clinical cases, and randomly selected cattle in a slaughterhouse survey for paratuberculosis. The overall sensitivity of the test, using the manufacturer's recommended cutoff was 45% ± 4.8%, and the specificity was 99% ± 0.9%. The ELISA result was significantly correlated with the number of colonies of M. paratuberculosis detected by fecal culturing. The sensitivity of the test was highest for clinical cases of paratuberculosis (87% ± 8.4%), and lowest for subclinical, light-shedding cattle (15% ± 6.6%). Changing the cutoff point did not improve performance of the test. Evaluating ELISA results with a kinetics-based method reduced plate-to-plate variation in results but did not improve performance of the test based on receiver-operating characteristic curve analysis.