bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood-Lipid and Lactation-Stage Factors Affecting Serum Vitamin E Concentrations and Vitamin E Cholesterol Ratios in Dairy Cattle
Authors: Herdt Thomas H. , Smith Jennifer C.
Published: May 2011

The distribution of cholesterol and vitamin E among the various lipoprotein density fractions in bovine blood was measured. The percentage of total plasma vitamin E and cholesterol in the various lipoprotein fractions was very-low-density lipoprotein, 2% and 2%, respectively; low-density lipoprotein, 17% and 22%, respectively; and high-density lipoprotein, 77% and 72%, respectively. Only 3% of plasma vitamin E was not associated with the lipoproteins. Vitamin E cholesterol ratios were not significantly different among lipoprotein fractions ( P = 0.3). These results indicate that vitamin E and cholesterol are distributed in equal proportions among lipoprotein fractions. Moreover, the results suggest that variation in the proportions of lipoproteins in the different density fractions would not affect the overall vitamin E cholesterol ratio of plasma. The results further imply that the total plasma vitamin E cholesterol ratio is a valid relative estimator of the vitamin E concentration per lipoprotein particle, regardless of the density distribution of particles. Total serum vitamin E and cholesterol concentrations and their ratio were then determined in commercial diary cattle in various phases of the lactation cycle. There was a significant lactation-stage effect on the serum concentration of each analyte, as well as on their ratio. However, the magnitude of the effect was much less for the ratio than for either vitamin E or cholesterol alone. These results imply that lactation stage affects serum vitamin E concentrations by influencing both the concentration of lipoprotein particles and the concentration of vitamin E within individual particles.
Gross and Microscopic Lesions in Porcine Fetuses Infected with Porcine Reproductive and Respiratory Syndrome Virus
Authors: Lager Kelly M. , Halbur Patrick G.
Published: May 2011

Diagnosis of porcine reproductive and respiratory syndrome virus (PRRSV)-induced reproductive failure in swine is difficult because of the rapid inactivation of virus in fetuses that have died prior to abortion or farrowing. In this report, we describe gross and microscopic lesions of diagnostic value found in fetuses transplacentally infected with PRRSV during late gestation. Seven sows free of PRRSV-specific antibody and 1 sow (#8) that had been previously infected with PRRSV were oronasally exposed to a PRRSV inoculum at or about 90 days of gestation (DG). One control sow (#9) was oronasally exposed to a sham inoculum at 90 DG. Sows were euthanized 21 days postexposure, and fetuses were tested for virus. Transplacental infection was detected in litters 1–7, and gross lesions of the umbilical cord were observed in some fetuses in 6 of the 7 litters. No transplacental infection or fetal lesions were found in litters 8 and 9. The gross lesions in the umbilical cords ranged from segmental hemorrhagic areas 1–2 cm in length to a full length involvement of the cord, which was grossly distended with frank hemorrhage. All live fetuses that had gross lesions in the umbilical cord were viremic, and histopathologic examination revealed a necrotizing umbilical arteritis with periarterial hemorrhage. This was the most consistent microscopic lesion in fetuses infected with PRRSV. Sows 1–7 had endometritis and myometritis of various degrees, suggesting PRRSV also may induce these lesions. Careful gross and microscopic examination of the umbilical cord may aid in the diagnosis of PRRSV-induced reproductive failure.
Morbilliviral Epizootic in Bottlenose Dolphins of the Gulf of Mexico
Authors: Lipscomb Thomas P. , Kennedy Seamus , Moffett Deborah , Krafft Amy , Klaunberg Brenda A. , Lichy Jack H. , Regan Gerald T. , Worthy Graham A. J. , Taubenberger Jeffery K.
Published: May 2011

Morbillivirus infection was diagnosed in 35/67 bottlenose dolphins (Tursiops truncatus) from the Gulf of Mexico that stranded from October 1993 through April 1994 in Alabama, Mississippi, and Texas (USA) during periods of increased dolphin standings in each of the 3 states. Diagnosis was based on histologic lesions, immunohistochemical demonstration of morbilliviral antigen, and detection of morbilliviral RNA by a reverse transcriptase polymerase chain reaction (RT-PCR) test performed on formalin-fixed, paraffin-embedded tissue (5 dolphins), on histologic lesions and detection of morbilliviral RNA by RT-PCR performed on formalin-fixed, paraffin-embedded tissue (1 dolphin), and on detection of morbilliviral RNA by RT-PCR performed on unfixed lung samples collected from carcasses with advanced postmortem autolysis (29 dolphins). Histologic lesions included proliferative interstitial pneumonia with syncytial cells and eosinophilic intranuclear and intracytoplasmic inclusion bodies, lymphoid depletion and syncytial cells with eosinophilic intranuclear inclusion bodies in lymph nodes, eosinophilic intracytoplasmic inclusion bodies in transitional epithelium of urinary bladder, and a syncytial cell with eosinophilic intranuclear inclusion bodies in epidermis. Concomitant pulmonary aspergillosis was diagnosed histologically in 4 dolphins. This is the 5th reported morbilliviral epizootic of aquatic mammals and the 2nd involving bottlenose dolphins in the United States.
Lesions in Lambs Experimentally Infected with Ovine Adenovirus Serotype 6 and Pasteurella Haemolytica
Authors: Cutlip Randall C. , Lehmkuhl Howard D. , Brogden Kim A. , Hsu Nan-Jung
Published: May 2011

Twenty-five colostrum-deprived lambs reared in isolation were inoculated with a US variant of ovine adenovirus serotype 6 (OAV-6) strain RTS-151, Pasteurella haemolytica, or a combination of the 2 agents. Although severe pulmonary lesions were caused by each agent, the lesions were more severe and lasted longer with the combined infection. Lesions induced by OAV-6 alone developed 6–9 days after inoculation and lasted for 15 days, the length of the experiment. The lesions were characterized by suppurative inflammation at the junction of the terminal bronchioles and alveoli. Air spaces were filled with neutrophils and sloughed epithelial cells, which often contained large intranuclear inclusions. Lesions induced by P. haemolytica alone developed within 1 day and persisted for no more than 10 days and were characterized by severe pulmonary edema with variable amounts of fibrin. Lesions induced by the combined infection had aspects of each infection alone and resulted in severe disease in 4 of 8 lambs that were permitted to live more than 1 day after inoculation with bacteria. Early pulmonary lesions included edema, limited fibrin deposition, and slight purulent bronchiolitis and alveolitis. Later lesions included necrosis and more fibrin. For lambs inoculated with both pathogens, resolution was incomplete 15 days after inoculation of virus (10 days after inoculation of P. haemolytica). The results presented here corroborate previous findings indicating that the RTS-151 variant of OAV-6 is common in lambs and acts in concert with P. haemolytica to cause severe and often fatal pneumonia.
A Dot Immunobinding Assay (Dot-ELISA) for the Rapid Serodiagnosis of Salmonella Enteritidis Infection in Chickens
Authors: Charles Samuel D. , Sreevatsan Srinand , Bey Russell F. , Sivanandan V. , Halvorson D. A. , Nagaraja Kakambi V.
Published: May 2011

A dot immunobinding assay (DIA) was developed for the detection of antibodies to Salmonella enteritidis. Western blot analysis of outer membrane proteins from SE identified 2 polypeptides of molecular masses 43 and 46 kD that were specific for S. enteritidis. These 2 polypeptides were utilized as antigens in the DIA. The DIA was tested on sera from chickens experimentally infected with S. enteritidis. Results of the DIA were compared with that of conventional microagglutination and serum plate tests. The DIA was a highly specific and sensitive test that can be useful for screening birds to determine if they are infected with S. enteritidis. Its simplicity, reliability, reproducibility, and speed in interpreting the assay results makes it a useful screening test for flock monitoring.
In Vitro Activity of Ceftiofur and its Primary Metabolite, Desfuroylceftiofur, against Organisms of Veterinary Importance
Authors: Salmon Sarah A. , Watts Jeffrey L. , Yancey Robert J.
Published: May 2011

Ceftiofur (XNL) and its primary metabolite, desfuroylceftiofur (DXNL), were evaluated for in vitro activity against 539 isolates from veterinary sources. Actinobacillus pleuropneumoniae, Pasteurella spp., Haemophilus somnus, Salmonella spp., Escherichia coli, staphylococci, and streptococci were tested. Overall, XNL and DXNL were equivalent in activity against the gram-negative organisms with all minimum inhibitory concentrations (MICs) within 1 serial dilution. Against the staphylococci, MIC differences of 2–3 serial dilutions were detected with an MIC90 for XNL and DXNL of 1.0 and 4.0–8.0 g/ml, respectively. Although the MIC90 obtained for Streptococcus suis for each compound was within 1 dilution, the MIC values against individual strains were 2–3 dilutions greater for DXNL than for XNL. The MICs obtained with the bovine and equine streptococci for DXNL (MIC90 = 0.03 g/ml) were 5 serial dilutions higher than those obtained for XNL (MIC90 £ 0.0019). Although DXNL was less active than XNL against the streptococci, these differences were not clinically important because both XNL and DXNL were highly active for these bacteria. Although these differences are of little importance with the streptococci, they may have important implications for susceptibility testing of the staphylococci. In conclusion, with the exception of the staphylococci, both XNL and DXNL were highly active against the organisms tested, with MICs for both compounds several fold lower than plasma levels achieved during dosing of XNL.
Minimum Inhibitory Concentration Breakpoints and Disk Diffusion Inhibitory Zone Interpretive Criteria for Tilmicosin Susceptibility Testing against Pasteurella Spp. Associated with Bovine Respiratory Disease
Authors: Shryock Thomas R. , White Donald W. , Staples J. Mitchell , Werner Carolyn S.
Published: May 2011

Tilmicosin is a novel macrolide antibiotic developed for exclusive use in veterinary medicine. The first tilmicosin-containing product was approved to treat bovine respiratory disease associated with pasteurellae. The development of antimicrobial susceptibility testing guidelines for tilmicosin was predicated on the relationship of clinical efficacy studies that demonstrated a favorable therapeutic outcome, on pharmacokinetic data, and on in vitro test data, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). The NCCLS-approved breakpoints for the MIC dilution testing are resistant ‡ 32 g/ml, intermediate 16 g/ml, and susceptible £ 8 g/ml. The zone of inhibition interpretive criteria for disk diffusion testing with a 15- g disk are resistant £ 10 mm, intermediate 11–13 mm, and susceptible ‡ 14 mm.
Evaluation of Nucleic Acid Amplification Methods for the Detection of Hog Cholera Virus
Authors: Harding Martha J. , Prud'homme Isabelle , Gradil Carlos M. , Heckert Robert A. , Riva José , McLaurin Richard , Dulac Gilles C. , Vydelingum Soopayah
Published: May 2011

A blind panel was tested in a diagnostic evaluation of a reverse transcription (RT) polymerase chain reaction (PCR) method for detecting hog cholera virus (HCV) from pig tissues. The capability of the RT-PCR test to discriminate between HCV and related pestiviruses, bovine viral diarrhea virus (BVDV), and those viruses causing similar diseases in swine, including African swine fever virus (ASFV) and pseudorabies virus (PRV), was also considered. Nucleic acid extraction involved either kit-based or conventional phenol: chloroform: isoamyl alcohol methods. A single-round PCR assay, using primers that hybridize to the conserved p 120 nonstructural gene region, was 82.5% sensitive ( n = 17) and 100% specific ( n = 18) in the detection of the presence of HCV RNA. However, the sensitivity was increased to 100% following a second PCR test. In all, 4 HCV, 7 BVDV, 2 ASFV, and 1 PRV isolates were studied. Novel nucleic acid sequences were generated for 9 HCV strains. Analysis of a portion of the p120 region using these methods was suitable for HCV isolate characterization.
Assessment of Maternal Antibody Decay and Response to Canine Parvovirus Vaccination Using a Clinic-Based Enzyme-Linked Immunosorbent Assay
Authors: Waner Trevor , Naveh Ami , Wudovsky Ilana , Carmichael Leland E.
Published: May 2011

Interference caused by maternal antibodies is considered a major cause of canine parvovirus (CPV) vaccination failure. In this study, an immunoblot clinic-based enzyme-linked immunosorbent assay (ELISA) method was used to detect CPV antibodies in sera of pregnant bitches and their offspring to study the response of pups to vaccination. With a easily accessible procedure for CPV antibody determination, the veterinarian should be able to gauge the response of pups after vaccination. The validity of the technique was tested in parallel against the standard hemagglutination inhibition (HI) test. Results of the ELISA were correlated with those of the standard HI method for quantification of CPV antibodies. With the ELISA, successfully immunized pups were identified, allowing for a more reliable and cost-effective program of vaccination. This simple clinic-based test could be used for the assessment of vaccination status of pups during the critical phase of 6 to about 16 weeks of age. This study is the first in which vaccination response to CPV in pups was followed, using a clinic-based ELISA for CPV antibody monitoring.
Intestinal Lesions Caused by Two Swine Chlamydial Isolates in Gnotobiotic Pigs
Authors: Rogers Douglas G. , Andersen Arthur A.
Published: May 2011

The objective of this study was to determine whether 2 distinct chlamydial isolates recovered from the intestines and feces of diarrheic nursery pigs could cause intestinal lesions in gnotobiotic pigs. Both isolates share biological characteristics with Chlamydia trachomatis. Chlamydial isolates R27 and R19 were propagated in Vero cells or embryonated eggs, respectively, and suspended in sucrose-phosphate-glutamine buffer with 10% fetal bovine serum for inoculation. Sham inocula were prepared from uninfected cell culture lysates and from uninfected eggs. Each piglet was fed 1 ml of inoculum or sham inoculum at 3–4 days of age. Ten piglets were each fed 109 inclusion-forming-units (IFU) and 14 piglets were each fed 106 IFU of isolate R27; 5 control piglets were fed sham inoculum. Twenty piglets were each fed 105 IFU R19; 5 control piglets were fed sham inoculum. All infected piglets developed diarrhea 4-5 days postinfection (DPI). Most piglets fed 109 IFU R27 became anorexic, dehydrated, and weak and were necropsied 4-7 DPI. Piglets fed 106 IFU R27 or 105 IFU R19 were necropsied 4, 7, 10, 14, and 18 DPI. Diarrhea, although never profuse, persisted in the piglets fed 106 IFU R27 or 105 IFU R19 through 12 DPI. At necropsy, all diarrheic piglets had watery colonic contents with flecks of undigested curd. In small intestine, histologic lesions were seen most consistently in distal jejunum and ileum. Distal jejunum and ileum from piglets fed 109 IFU R27 and necropsied 4–5 DPI were characterized by villus atrophy and multifocal necrosis of villi; necrosis was limited to the tips or apical one half of villi. Mild to severe villus atrophy, lymphangitis, and perilymphangitis were seen in the distal jejunum and ileum from all infected piglets 7 and 10 DPI. Colon from 1 infected piglet necropsied 10 DPI had mild focal serositis; significant colonic lesions were not seen in the other infected piglets. Immunostaining done on sections of distal jejunum and ileum revealed chlamydial antigen in villus enterocytes, occasional goblet cells, and occasional cryptal enterocytes and in foci of lymphangitis and perilymphangitis; the amount of detectable chlamydial antigen decreased after 4 DPI. In colon, sparse positive staining was seen in surface enterocytes and cryptal enterocytes. Ultrastructural examination of ileal villus enterocytes revealed chlamydiae, often together with glycogen particles, in vacuoles or occasionally free in the cytoplasm. The results indicated that the swine chlamydial isolates used in this study are intestinal pathogens in gnotobiotic pigs.
Serologic Responses of Brucella Abortus Strain 19 Calfhood-Vaccinated Cattle Following Adult Vaccination with Strain RB51
Authors: Olsen S. C. , Evans D. , Hennager S. G. , Cheville N. F. , Stevens M. G.
Published: May 2011

This study was designed to determine if Brucella abortus strain RB51, which expresses small amounts of the lipopolysaccharide O side chain, would cause positive responses on brucellosis serologic surveillance tests when given to adult cattle that were vaccinated as calves with B. abortus strain 19. Cattle vaccinated as adults with strain RB51 that had been vaccinated as calves with strain 19 ( n = 40) had significantly greater antibody titers ( P < 0.05) against strain RB51 at 4 and 8 weeks postvaccination in the dot blot assay than did animals ( n = 10) not vaccinated with strain RB51. When evaluated using the card or buffered acid plate agglutination presumptive tests, 7 strain RB51 vaccinates tested positive at either 4 or 8 weeks following vaccination as compared with 4 cattle in the control group that were not vaccinated with strain RB51. One strain RB51 vaccinate was scored as suspect on the standard tube agglutination (STA) test at 8 weeks following vaccination. Remaining samples from strain RB51 vaccinates tested negative on the STA, complement fixation (CF), rivanol, and particle concentration fluorescence immunoassay (PCFIA) confirmatory tests. Samples from 2 control cattle were PCFIA positive at time 0; 1 of these animals was CF positive throughout the study. This study suggests that use of strain RB51 in cattle vaccinated with strain 19 as calves will not cause positive responses on confirmatory tests and will not impair brucellosis serologic surveillance efforts.
Detection of Toxigenic Pasteurella Multocida Infections in Swine Herds by Assaying Antibodies in Sow Colostrum
Authors: Levonen K. , Frandsen P. L. , Seppänen J. , Veijalainen P.
Published: May 2011

Toxigenic Pasteurella multocida is the causative agent of progressive atrophic rhinitis (PAR), a serious respiratory infection of swine. Diagnosis of the disease has hitherto been based on clinical signs, pathologic findings, and subsequent isolation of the agent. The best Finnish pig breeding herds participating in the Finnish Pig Health Scheme have been surveyed for PAR since 1963, and the disease has been eradicated from these herds. In this study, a total of 5,650 colostrum samples from 188 Finnish Pig Health Scheme herds were analyzed with a new serologic screening method: an enzyme-linked immunosorbent assay (ELISA) able to detect antibodies to the toxin of P. multocida (PMT). Although the herds had been continuously controlled for PAR, 1 herd with PMT antibodies was found. The positive reactions in the ELISA were confirmed by isolating the causative organism. The origin of the infection also appeared to be obvious. The serologic ELISA is a suitable method for the detection and screening of toxigenic P. multocida-infected pig herds.
Interpretive Criteria for Antimicrobial Susceptibility Testing of Ceftiofur against Bacteria Associated with Swine Respiratory Disease
Authors: Burton Pamela J. , Thornsberry Clyde , Yee Y. Cheung , Watts Jeffrey L. , Yancey Robert J.
Published: May 2011

Ceftiofur, an extended-spectrum cephalosporin, is active against a variety of animal pathogens, including organisms associated with swine respiratory disease. However, minimum inhibitory concentration (MIC) breakpoint and disk diffusion interpretive criteria have not been established for swine pathogens. Susceptibility tests were performed by broth microdilution MIC and disk diffusion methods on 246 bacterial species that cause swine respiratory disease. Ceftiofur was active against Salmonella sp., Pasteurella multocida, Actinobacillus pleuropneumoniae, Streptococcus suis, and Escherichia coli but was not active against Bordetella bronchiseptica measured by MIC. Based on pharmacokinetic studies of ceftiofur in swine after a single intramuscular injection of 3 or 5 mg/kg body weight of ceftiofur and on the MIC and disk diffusion data, we recommend MIC breakpoints and disk diffusion distances, respectively, of ≤ 2 μg/ml and ≥ 21 mm for susceptible, 4 μg/ml and 18–20 mm for intermediate, and ≥ 8 μg/ml and ≤ 17 mm for resistant classification for swine pathogens. When these breakpoints were applied to data from a previous study using bovine pathogens, only 1 minor interpretive error occurred.
Comparison of Polyclonal Antibodies to Three Different Preparations of Mycobacterium Paratuberculosis in Immunohistochemical Diagnosis of Johne's Disease in Cattle
Authors: Stabel Judith R. , Ackermann Mark R. , Goff Jesse P.
Published: May 2011

Polyclonal antisera were raised in rabbits against preparations of live and heat-killed Mycobac- terium paratuberculosis and cell-wall proteins of M. paratuberculosis and were evaluated as diagnostic tools in immunohistochemical staining of bovine tissue. Live preparations of M. paratuberculosis (LMp) were inoculated intraperitoneally or intravenously at 109/ml. Heat-killed M. paratuberculosis (HKMp) was prepared by treatment of bacteria at 85 C for 10 minutes. Cell-wall proteins were isolated from M. paratuberculosis and conjugated to keyhole limpet hemocyanin to improve antigenicity (KLH-CWPMp). The HKMp and KLH-CWPMp preparations were emulsified in incomplete Freund's adjuvant before subcutaneous inoculation of rabbits. Antibody titers in the terminal blood sample were higher for HKMp and KLH-CWPMp than for LMp rabbits (1:1,024 vs. 1:64). The KLH-CWPMp antibody did not cross-react with M. bovis-infected tissues. Sensitivity and specificity of immunohistochemical detection of Johne's disease (paratuberculosis) from bovine tissues was much higher for the KLH-CWPMp polyclonal antibody. Immunoreactivity of the antibody resulted in staining of bacteria in the cytoplasm of macrophages, mononuclear giant cells, and extracellular bacteria in both intestine and lymph node.
A Comparative Study on the use of Virus and Antibody Detection Techniques for the Diagnosis of La Piedad Michoacan Paramyxovirus (LPMV) Infection in Pigs
Authors: McNeilly F. , Walker I. , Allan G. M. , Foster J. C. , Linne T. , Merza M. , Hernandez P. , Kennedy S. , Adair B.
Published: May 2011

La Piedad Michoacan paramyxovirus (LPMV) is newly recognized paramyxovirus that has been associated with neurologic and reproductive disorders in pigs in Mexico. To date, no comparative study of methods for the diagnosis of infection with this virus has been published. In this study, we identified tissues containing maximum virus load to optimize virus isolation procedures, and we compared this method to a rapid diagnostic test employing immunostaining of impression smears for LPMV antigens. In addition, several of the available tests for detecting LPMV antibodies were compared for their sensitivity in detecting seroconversion. Pigs used for the study of virus load in tissues and serologic studies were inoculated at 17 days of age with 107.00 TCID50 of LPMV. Serial blood samples were collected from selected pigs, and selected pigs were necropsied over a 14-day period. Pigs used in the investigation comparing standard virus isolation techniques to immunostaining of impression smears were inoculated at 3 days of age as described above and necropsied over an 8-day period. The results demonstrate that in the 17-day-old pigs maximum virus titers were detected in olfactory bulb at 5 days postinoculation (PI) and in midbrain at 9 days PI. In addition, the most consistent recovery of high titer virus was from tonsil (3–9 days PI) and olfactory bulb (4–9 days PI). Immunostaining of impression smears was as sensitive as virus isolation when selected tissues (lung, midbrain, olfactory bulb) were compared, with virus detected by both methods in 11/13 samples and in 1 sample each by immunostaining and virus isolation, respectively. All of the serology tests investigated detected seroconversion in pigs by 8 days PI. The identification of target organs where highest virus titers are found combined with immunofluorescent methods for the detection of LPMV antigens and a comparative study of the available serologic tests should facilitate the selection of techniques suitable for any laboratory to diagnose LPMV infection in pigs.
Infectious Agents in Acute Respiratory Disease in Horses in Ontario
Authors: Carman Suzanne , Rosendal Søen , Huber Leslie , Gyles Carlton , McKee Sharyn , Willoughby Russell A. , Dubovi Ed , Thorsen Jan , Lein Don
Published: May 2011

A study of acute respiratory disease in horses in Ontario was undertaken to determine the identity of current causative infectious agents. A nasopharyngeal swab was designed and utilized to maximize isolation of viruses, mycoplasma, and pathogenic bacteria. Serum samples were collected for parallel determination of antibody titers to equine influenza virus type A subtype 1 (H7N7) and subtype 2 (H3N8), equine rhinovirus types 1 and 2, equine herpesvirus type 1, Mycoplasma equirhinius, and Mycoplasma felis. Equine rhinovirus type 2 was recovered from 28/92 horses tested, and equine influenza virus type A, subtype 2, was recovered from 5. The mycoplasma and bacteria isolated were consistent with those commonly associated with nonspecific respiratory diseases in horses, except that Streptococcus pneumoniae capsular type 3 was isolated from 10 horses.
Herd-Based Diagnosis of Neospora Caninum-Induced Endemic and Epidemic Abortion in Cows and Evidence for Congenital and Postnatal Transmission
Authors: Thurmond Mark C. , Hietala Sharon K. , Blanchard Patricia C.
Published: May 2011

Aborting and nonaborting cows and their dams or daughters were studied to determine if herd abortion problems were associated with the presence of Neospora caninum antibodies and to estimate when aborting cows may have acquired the infection. Cows were sampled from 20 herds that had experienced an abortion epidemic presumed to have been caused by N. caninum and from 2 herds experiencing endemic abortion. Seroprevalence for 14 herds experiencing an epidemic ranged from 7% to 70%, as estimated by enzyme-linked immunosorbent assay. A strong association between seropositivity and abortion was found for only 5 of 14 herds with a presumed diagnosis of N. caninum abortion ( P ≤ 0.015, lower 95% confidence interval of odds ratio ≥ 1.2), indicating N. caninum may be overdiagnosed as the cause of an abortion epidemic in some herds. No association was found between dam and daughter seropositivity for herds experiencing an epidemic ( P ≥ 0.17), suggesting that most cows aborting during an epidemic were infected postnatally. For the 2 herds with endemic abortion (A, B), odds of an aborting cow having N. caninum antibodies were 3.4-fold (herd A) and 7.0-fold (herd B) higher than odds for nonaborting cows ( P ≤ 0.05). Cows that aborted a fetus infected with N. caninum were more likely to have had a previous seropositive daughter than were nonaborting seronegative cows ( P ≤ 0.0025), suggesting that infection had been acquired before conception of the aborted fetus.
The Prevalence of Shedding of Cryptosporidium and Giardia Spp. Based on a Single Fecal Sample Collection from Each of 91 Horses used for Backcountry Recreation
Authors: Johnson E. , Atwill E. R. , Filkins M. E. , Kalush J.
Published: May 2011

Cryptosporidium parvum and Giardia duodenalis are now recognized as primary enteric pathogens in animals and humans. Regulatory agencies, such as the Environmental Protection Agency are under increasing pressure to reduce the concentration of these protozoa in surface waters. Given the popularity of recreational riding of horses on public land in California backcountry, concerns have been raised by various regulatory agencies as to whether horses used for backcountry recreation are a significant source of C. parvum and G. duodenalis for the environment. The prevalence of fecal shedding of Cryptosporidium and Giardia in horses with a history of being ridden in California backcountry during 1993 and 1994 was estimated. Using both direct fluorescent antibody and levitation centrifugation tests, none of 91 single-collection fecal samples from throughout California had Cryptosporidium oocysts or Giardia cysts. Horses ranged from 4 to 24 years of age. Because none of the 91 samples, collected 1 time from each horse, were positive and assuming that the sensitivity and specificity of the test methods employed were 100%, the highest probable prevalence of shedding for either protozoal pathogen was < 3.2% for the cohort of horses studied.
Four-Hour Processing of Clinical/Diagnostic Specimens for Electron Microscopy using Microwave Technique
Authors: Giberson Richard T. , Demaree Richard S. , Nordhausen Robert W.
Published: May 2011

A protocol for routine 4-hour microwave tissue processing of clinical or other samples for electron microscopy was developed. Specimens are processed by using a temperature-restrictive probe that can be set to automatically cycle the magnetron to maintain any designated temperature restriction (temperature maximum). In addition, specimen processing during fixation is performed in 1.7-ml microcentrifuge tubes followed by subsequent processing in flow-through baskets. Quality control is made possible during each step through the addition of an RS232 port to the microwave, allowing direct connection of the microwave oven to any personal computer. The software provided with the temperature probe enables the user to monitor time and temperature on a real-time basis. Tissue specimens, goat placenta, mouse liver, mouse kidney, and deer esophagus were processed by conventional and microwave techniques in this study. In all instances, the results for the microwave-processed samples were equal to or better than those achieved by routine processing techniques.
Emerging Diseases — What Veterinarians Need to Know
Authors: Brown Corrie
Published: May 2011

The recent increase in emerging diseases can be attributed to a number of factors, all of which relate to some form of alteration in the way etiologic agents move around. Some of these factors responsible for altered agent trafficking include actual transport to a susceptible population or new species, environmental disruption that facilitates exchange of microbes, and a husbandry change that promotes new ways for microbes to move around. Given the exponential growth of the human population and all the attendant implications, including the mobility of this population, the ecological disruption that is accompanying the overall increase, and the necessity of exploring new agricultural technologies to feed a burgeoning population, it is a certainly that altered agent trafficking will not only continue but will undoubtedly increase. Veterinarians should be aware of the role they will be expected to play in this field.
Bluetongue Virus Detection: A Safer Reverse-Transcriptase Polymerase Chain Reaction for Prediction of Viremia in Sheep
Authors: Shad G. , Wilson W. C. , Mecham J. O. , Evermann J. F.
Published: May 2011

A reversible target capture viral RNA extraction procedure was combined with a reverse-transcriptase nested polymerase chain reaction (PCR) to develop a capture PCR assay providing a rapid and safe prediction method for circulating bluetongue virus in infected ruminants. This new assay was compared with virus isolation and a recently developed antigen-capture enzyme-linked immunosorbent assay (ELISA) for the detection of bluetongue virus. Eight Warhill crossbred sheep were inoculated subcutaneously with bluetongue virus serotype 10, and blood samples were taken sequentially over a period of 28 days. The capture PCR detected the peak of viremia, as determined by virus isolation and antigen-capture ELISA, from day 5 to day 14 after challenge. The results indicate that the rapid-capture bluetongue virus PCR provides a rapid indicator of samples in which virus can be isolated. In addition, this capture bluetongue virus PCR procedure does not require a lengthy phenol extraction or the use of the highly toxic methyl mercury hydroxide denaturant.
Serologic Reactivity Using Conserved Envelope Epitopes in Feline Lentivirus-Infected Felids
Authors: Kania Stephen A. , Kennedy Melissa A. , Potgieter L. N. D.
Published: May 2011

An enzyme-linked immunosorbent assay (ELISA) based on synthetic peptides identical to lentivirus envelope protein amino acid sequences was used to study serologic reactivity of lentivirus-infected domestic cats and nondomestic felids. One feline immunodeficiency virus (FIV) peptide, P237, was consistently recognized by antibodies from FIV-infected cats, but 2 other FIV peptide antigens were not. The molecular basis for this serologic reactivity was examined. Lentivirus-infected nondomestic Felis species reacted intensely with a puma lentivirus (PLV) peptide corresponding to the conserved FIV peptide. However, lentivirus-infected Panthera species, from which a different lentivirus has been isolated, did not react with the PLV. FIV-infected domestic felids also did not have significant reactivity with the PLV peptide. The peptide ELISA is comparable in sensitivity and specificity to western blot analysis and a commercial enzyme immunoassay. Unlike the other assays, however, the peptide ELISA is inexpensive, requires a small amount of serum, enables the study of specific isotype reactivity, and discriminates between antibodies to FIV and those to PLV. Antibody tests based upon the FIV and the PLV peptides should be useful for detecting the possible introduction of FIV into exotic felids or of lentiviruses from nondomestic felids into the domestic cat population.
Development and Evaluation of a Recombinant Antigen, Monoclonal Antibody-Based Competitive ELISA for Heartwater Serodiagnosis
Authors: Katz Jonathan B. , DeWald Rick , Dawson Jacqueline E. , Camus Emanuel , Martinez Dominique , Mondry Ricarda
Published: May 2011

Cowdria ruminantium is the etiologic agent of heartwater, a tick-transmitted foreign animal disease with considerable potential for entrance into the USA. A competitive enzyme-linked immunosorbent assay (cELISA) was developed to detect serologic responses to C. ruminantium infection. The cELISA utilized a recombinant form of the C. ruminantium major antigenic protein (MAP-1) as the antigen and an anti-MAP-1 monoclonal antibody as the competing indicator reagent. Experimental antisera to C. ruminantium and a wide variety of related ehrlichial organisms were used to evaluate cELISA reactivity. Only sera against C. ruminantium, Ehrlichia canis, E. chaffeensis, and a recently discovered cervine ehrlichia-like organism reacted positively in the cELISA. Specificity of the cELISA was 299.5% in a survey of 1,774 southeastern US and Puerto Rican slaughter cattle sera but was only 85% in a group of 79 hunter-killed white-tailed deer ( Odocoileus virginianus) from the southeastern USA. Reference true-positive and cELISA false-positive sera were further analyzed by end point titrations using the cELISA and by indirect fluorescent antibody (IFA) tests for reactivity with C. ruminantium, E. canis, and E. chaffeensis antigens. True heartwater-positive sera were significantly more reactive using the cELISA and C. ruminantium IFA procedures ( P < 0.05), whereas false-positive sera were significantly more reactive with the antigens used in the E. chaffeensis IFA procedure ( P < 0.05). A group of sera from 210 field-origin ruminants residing on known or potentially heartwater-endemic Caribbean islands revealed a substantial (12.4%) prevalence of cELISA-positive specimens. The cELISA is a relatively specific serodiagnostic test for heartwater in cattle and could be used to monitor for possible introduction of the disease into the USA. The cELISA may also be an excellent tool for monitoring the success of an ongoing Caribbean Amblyomma tick eradication program designed to eliminate the biological vector responsible for the perpetuation and spread of this dangerous foreign animal disease.
Experimental Vesicular Stomatitis in Swine: Effects of Route of Inoculation and Steroid Treatment
Authors: Howerth Elizabeth W. , Stallknecht David E. , Dorminy Mark , Pisell Tracy , Clarke Gerard R.
Published: May 2011

An enzootic focus of vesicular stomatitis virus New Jersey serotype (VSV-NJ) exists on Ossabaw Island, Georgia. Many questions regarding the epizootiology of this virus at this focus still exist, but evidence suggests that the vector for this virus is a phlebotomine sand fly ( Lutzomyia shannoni), with feral swine serving as a potential source of virus for the sand fly and for other swine via contact transmission. We conducted 2 experimental trials in domestic swine using VSV-NJ isolated from a sand fly from Ossabaw Island to determine if route of inoculation or immunosuppression via steroid administration affected the development of disease, viremia, viral shedding, or the neutralizing antibody response. In a third trial, we studied the potential for contact transmission among swine using this isolate. Virus isolations were made from nasal cavity or palatine tonsil of the soft palate, and VSV-NJ neutralizing antibodies developed when pigs were inoculated intradermally in the apex of the snout, ear, or coronary band, intravenously, intranasally, or via scarification of the apex of the snout or coronary band. Vesicles developed only in pigs inoculated in the apex of the snout or coronary band, and these vesicles were at the site of inoculation. Steroid treatment did not potentiate the development of secondary vesicles and did not prolong the period of virus shedding from VSV-NJ-infected swine. Contact transmission, as determined by shedding of virus from the tonsil of the soft palate and the development of VSV-NJ neutralizing antibodies, occurred in pigs in contact with animals inoculated in the apex of the snout but not in contact animals exposed to pigs inoculated intradermally in the coronary band or intranasally. These trials show that contact transmission can occur and VSV-NJ can be shed without the development of clinical disease (i.e., vesicle formation). Viremia was never detected in any of the experimental pigs, suggesting that swine may not be a good amplifying host for VSV-NJ.
Restriction Endonuclease Analysis of Equine Herpesvirus-1 Isolates Recovered in Ontario, 1986–1992, from Aborted, Stillborn, and Neonatal Foals
Authors: Nagy Éva , Idamakanti Neeraja , Carman Susy
Published: May 2011

Ninety-two equine herpesvirus type 1 isolates were recovered from aborted, stillborn, or neonatal foals from Ontario, Canada, from 1986 to 1992. From this total, 32 strains were randomly chosen for further study. Four or 5 isolates from each winter were selected, each from a different premises, and characterized by restriction enzyme analysis using BamHI, KpnI, BglII, HindIII, and EcoRI. Additional isolates from 2 premises and from a zebra foal were also assessed. For the strains isolated in 1986 and 1989–1992, the DNA pattern of 18 strains was similar to that of type 1P (Kentucky D) for BamHI and KpnI. None of the 32 strains studied could be differentiated by HindIII or EcoRI. Using BglII, an inconsistent fragment pattern and distribution were observed. Of the 8 strains isolated in 1987 and 1988, 7 were assigned into the 1B prototype group. The geographic distribution of 17 type 1P and 12 1B isolates was random across southern Ontario. These findings suggest that both electropherotypes can be recovered from horses in Ontario. The patterns of the additional equine isolates from the same premises were identical. The zebra isolate was different from the prototype equine herpesvirus type 1 and type 4 patterns and from all other equine isolates.
A Novel Protein Polymorphism Differentiates the California Serotype of Infectious Bronchitis from other Serotypes Common to California
Authors: Case James T. , Sverlow Karen W. , Reynolds Bruce J.
Published: May 2011

The California (Cal) serotype of infectious bronchitis virus (IBV) was isolated from layer flocks in southern California in the early 1980s. Since then, it has spread to the broiler-producing regions of central California, where it has been implicated in respiratory disease outbreaks in vaccinated flocks. Lack of a procedure for quickly identifying IBV serotypes in commercial chicken flocks has prevented the causal association of the IBV Cal serotype with respiratory disease outbreaks. A protein polymorphism has been identified in the matrix protein of the Cal serotype; it appears to be unique among other common serotypes of infectious bronchitis virus found in California. This polymorphism can be identified on western blots using raw or concentrated infectious allantoic fluid as the source material. Identification of the Cal serotype and of serotypes in the Mass and Conn groups can be performed rapidly using field samples from suspect flocks. The identification of this polymorphism provides an alternative method for the rapid identification of the Cal serotype of IBV.
Two New Serovars of Chlamydia Psittaci from North American Birds
Authors: Andersen Arthur A.
Published: May 2011

Five Chlamydia psittaci isolates (1 turkey, 1 psittacine, 1 human, and 2 pigeon isolates) failed to react with serovar-specific monoclonal antibodies to known avian and mammalian C. psittaci serovars and were presumed to represent 1 or more new serovars. The isolates were characterized using restriction endonuclease analysis of the whole genome, polymerase chain reaction-restriction fragment length polymorphism of the major outer membrane protein genome, monoclonal antibody comparisons, and growth in tissue culture. Monoclonal antibodies were produced to the human isolate (MP) and to the psittacine isolate (VS225). The monoclonal antibody results show that the isolates represent 2 new avian serovars (serovars E and F). The restriction fragment length polymorphism analysis of the major outer membrane protein genome demonstrated that the isolates are distinct. The whole genome restriction endonuclease analysis data and the growth patterns in tissue culture indicate that the new serovars are similar to avian serovars recognized previously. A subspecies monoclonal antibody that reacted with serovars A and B also reacted with serovar E, indicating that these serovars are closely related. The results show that these isolates represent 2 new avian serovars, making them the fifth and sixth avian serovars identified in North American birds.
Bovine Fetal Neosporosis: A Comparison of Epizootic and Sporadic Abortion Cases and Different Age Classes with Regard to Lesion Severity and Immunohistochemical Identification of Organisms in Brain, Heart, and Liver
Authors: Wouda W. , Moen A. R. , Visser I. J. R. , van Knapen F.
Published: May 2011

Eighty bovine fetuses with confirmed neosporosis were used to score lesion severity and presence of parasites in brain, heart, and liver. A comparison was made between epizootic and sporadic abortion cases. The possible influence of fetal age was also investigated. Histologic lesions of multifocal encephalitis, myocarditis, and periportal hepatitis with or without focal hepatocellular necrosis were almost always observed. Neospora caninum tachyzoites were identified immunohistochemically in 85% of the brains, 14% of the hearts, and 26% of the livers. Tissue cysts were observed in 21% of the brains. Significant differences between epizootic and sporadic abortion cases were found only in the liver. Hepatic lesions were more prominent and N. caninum tachyzoites were observed more frequently and in higher numbers in epizootic cases. Examination by immunohistochemistry of the liver in addition to the brain can be highly contributive diagnostically, particularly in epizootic cases. There were no significant age-related differences except for a higher presence of tachyzoites in the hearts of younger fetuses (3-4 months gestational age).
Polymerase Chain Reaction and Restriction Endonuclease Digestion for Selected Members of the “Mycoplasma Mycoides Cluster” and Mycoplasma Putrefaciens
Authors: Rodriguez Jose L. , Ermel Richard W. , Kenny Thomas P. , Brooks Dale L. , DaMassa Al J.
Published: May 2011

A specific diagnostic method using the polymerase chain reaction, together with restriction endonuclease digestion patterns, was developed for members of the “ Mycoplasma mycoides cluster” that normally occur in the United States (i.e., Mycoplasma mycoides subsp. mycoides Large Colony and Mycoplasma capricolum subsp. capricolum in addition to “cluster” mycoplasma, bovine serogroup 7, and Mycoplasma putrefaciens. The digestion of “cluster” polymerase chain reaction DNA (1,225 bp) amplification products with restriction enzymes Asel and SspI gave mycoplasma species-specific patterns for all strains of M. mycoides subsp. mycoides Large Colony, M. capricolum subsp. capricolum, and bovine group 7 tested. Moreover, we found a nonspecific amplification product for M. putrefaciens that occurred with the oligonucleotide primers used for the “ M. mycoides cluster” reaction. However, the restriction endonuclease digestion patterns observed with the restriction enzymes AluI, AseI, and SspI for M. putrefaciens were different than the digestion patterns obtained for the other “cluster” mycoplasmas. This report confirms the usefulness of polymerase chain reaction DNA amplification allied with restriction enzyme digestion profile analysis for the rapid and specific identification of mycoplasmas belonging to the “ M. mycoides cluster” and M. putrefaciens.
Detection and Differentiation of Primate α-herpesviruses by PCR
Authors: Black Daria H. , Eberle R.
Published: May 2011

A rapid method for detection and differentiation of 5 primate αpha-herpesviruses (human herpes simplex virus types 1 and 2 [HSV1, HSV2], green monkey simian agent 8, baboon herpesvirus 2 [HVP2], and macaque B virus [BV]) was developed utilizing the polymerase chain reaction (PCR). PCR primers were located in conserved regions of the gene encoding the glycoprotein B, which flanks an intervening region that is highly divergent among the 5 viruses. Amplified PCR products from the 5 viruses were readily differentiated by their unique restriction enzyme digestion patterns. No variation in digestion patterns was noted among strains of HSV1, HSV2, or HVP2. One clinical isolate of BV exhibited variation in a single restriction site, but its overall restriction pattern remained typical of BV. This method (PCR/RFLP) allowed the presence of herpesvirus DNA in clinical swabs from primates to be readily detected and the virus unambiguously identified.
Immunohistochemical Detection of Haemophilus Parasuis Serovar 5 in Formalin-Fixed, Paraffin-Embedded Tissues of Experimentally Infected Swine
Authors: Segalés Joaquim , Domingo Mariano , Solano Gloria I. , Pijoan Carlos
Published: May 2011

An avidin-biotin complex immunohistochemistry technique was developed to detect Haemophilus parasuis serovar 5 in experimentally infected 18-21-day-old conventional pigs, using a rabbit polyclonal antiserum. Seven of 10 intratracheally inoculated animals developed a low to medium degree of fibrinous polyserositis; meninges and pleura were the most severely affected areas. Haemophilus parasuis was recovered from 9 of 10 pigs; in 2 of them H. parasuis was isolated from tracheal swabs only. Positive immunohistochemistry results, mainly observed as free bacteria or bacteria within inflammatory cell cytoplasm in the fibrinopurulent exudate, were observed in 8 of 10 animals. Cross-reactivity with Actinobacillus pleuropneumoniae was detected but not with other gram-positive and gram-negative bacteria tested. This immunohistochemistry technique seemed to be at least as sensitive as microbiologic cultures and could be useful in studies of pathogenesis and retrospective diagnosis. However, cross-reactivity with A. pleuropneumoniae means that positive immunohistochemistry results in lung tissue from field cases would be dubious.