Affiner votre recherche
Résultats 141-150 de 465
First molecular isolation of <i>Mycoplasma ovis</i> from small ruminants in North Africa
2015
Mohamed R. Rjeibi | Mohamed A. Darghouth | Houda Omri | Khemaïs Souidi | Mourad Rekik | Mohamed Gharbi
Eperythrozoonosis is a small ruminant disease caused by the bacterium Mycoplasma ovis (formerly known as Eperythrozoon ovis). Whilst acute infection in sheep may result in an anaemia and ill thrift syndrome, most animals do not develop clinical signs. Molecular methods were used to compare and evaluate the prevalence of infection with M. ovis in sheep and goats in Tunisia. A total of 739 whole blood samples from 573 sheep and 166 goats were tested for the M. ovis 16S rRNA gene using PCR. The overall prevalence was 6.28% ± 0.019 (36/573). Only sheep were infected with M. ovis (p < 0.001), and the prevalence was significantly higher in central Tunisia (29.2%) compared with other regions (p < 0.05). The prevalence revealed significant differences according to breed and bioclimatic zones (p < 0.001). Furthermore, the prevalence in young sheep (35/330; 10.6%) was higher than in adults (1/243; 0.41%) (p < 0.001). Only sheep of the Barbarine breed were infected, with a prevalence of 11.8% (p < 0.001). This is the first molecular study and genetic characterisation of M. ovis in North African sheep breeds.
Afficher plus [+] Moins [-]Clonal distribution of Streptococcus suis isolated from diseased pigs in the central region of Chile
2015
Morales, Barbara | Ruíz Rodríguez, Alvaro | Lacouture, Sonia | Gottschalk, Marcelo
The characteristics of 29 Chilean field strains of Streptococcus suis recovered between 2007 and 2011 from pigs with clinical signs at different farms were studied. Serotyping with use of the coagglutination test revealed that all but 1 strain belonged to serotype 6; the remaining strain was serotype 22. All the serotype-6 strains were suilysin (hemolysin)-negative; in addition, they were found to be genotypically homogeneous by enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction (ERIC-PCR) and sensitive to ampicillin, ceftiofur, penicillin, and trimethoprim/sulfamethoxazole. The results indicate that, in contrast to what is generally observed in other countries, a single clone of S. suis was isolated from diseased pigs in the central region of Chile.
Afficher plus [+] Moins [-]Evaluation of species differences and the effects of storage duration and temperature on the anticollagenase efficacy of canine, feline, and equine serum on in vitro corneal degradation
2015
Conway, Emily D. | Stiles, Jean | Townsend, Wendy M. | Weng, Hsin-Yi
OBJECTIVE To evaluate species differences and effects of storage duration and temperature on the anticollagenase efficacy of canine, feline, and equine serum on in vitro corneal degradation. SAMPLES Corneas and serum from dogs, cats, and horses. PROCEDURES Clinically normal corneas from dogs, cats, and horses were harvested within 2 hours after euthanasia. Serum samples from dogs, cats, and horses were collected and pooled by species. Corneal specimens were incubated with collagenase derived from Clostridium histolyticum, 5mM calcium chloride in saline (0.9% NaCl) solution, and feline, canine, or equine serum that had been stored for 0, 30, 90, or 180 days at −20° or −80°C. Following incubation, the corneal weight loss percentage and hydroxyproline concentration in the incubation fluid were calculated and compared among experimental combinations. RESULTS Feline serum was more effective than canine or equine serum for minimizing corneal weight loss. Incubation with feline or equine, but not canine, serum significantly reduced hydroxyproline production. Serum storage duration did not affect corneal weight loss, but the hydroxyproline concentration was greater for corneal specimens that were incubated with serum that was stored for 90 days, compared with that for corneal specimens incubated with serum that was stored for 0, 30, or 180 days. Serum storage temperature did not affect corneal weight loss or hydroxyproline concentration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that serum reduced corneal degradation in vitro, and the duration and temperature at which serum was stored did not affect its anticollagenase efficacy.
Afficher plus [+] Moins [-]The effect of dystocia on physiological and behavioral characteristics related to vitality and passive transfer of immunoglobulins in newborn Holstein calves
2015
Murray, Christine F. | Veira, Doug M. | Nadalin, Audrey L. | Haines, Deborah M. | Jackson, Marion L. | Pearl, David L. | Leslie, Ken E.
The objective of this study was to examine the effect of calving difficulty or dystocia on the vitality of newborn calves and its association with blood pH, the apparent efficiency of immunoglobulin G (IgG) absorption (AEA), and weight gain. A total of 45 calving events (N = 48 calves) were monitored from the first sight of fetal membranes. All calves were assessed at the time of first attaining sternal recumbency (SR), at 2 and 24 h, and at 7 and 14 d of age. Measurements included time to SR, rectal temperature, respiration and heart rate, analysis of blood gases and other blood measures, suckling response, time to standing, passive transfer of IgG, and weight gain. Calves were separated from their dam 2 h after birth and fed a commercial colostrum replacer containing 180 g of IgG by esophageal tube feeder. Calves born following dystocia had lower venous blood pH and took longer to attain SR and attempt to stand than those born unassisted. Duration of calving interacted with the number of people required to extract the calf by pulling as a significant predictor of pH at SR. No association was found between pH at SR and AEA. However, reduced AEA was found in calves that were female and in calves that did not achieve SR within 15 min of birth. A longer calving duration, being born in July or August rather than June, and a shorter time spent standing in the first 2 d of life were significantly associated with reduced weight gain to 14 d. It was concluded that factors at calving impact the physiology, vitality, and subsequent weight gain of newborn calves.
Afficher plus [+] Moins [-]Role of the capsular polysaccharide as a virulence factor for Streptococcus suis serotype 14
2015
Roy, David | Auger, Jean-Philippe | Segura, Mariela | Fittipaldi, Nahuel | Takamatsu, Daisuke | Okura, Masatoshi | Gottschalk, Marcelo
Streptococcus suis is an important swine pathogen and a zoonotic agent causing meningitis and septicemia. Although serotype 2 is the most virulent type, serotype 14 is emerging, and understanding of its pathogenesis is limited. To study the role of the capsular polysaccharide (CPS) of serotype 14 as a virulence factor, we constructed knockout mutants devoid of either cps14B, a highly conserved regulatory gene, or neu14C, a gene coding for uridine diphospho-N-acetylglucosamine 2-epimerase, which is involved in sialic acid synthesis. The mutants showed total loss of the CPS with coagglutination assays and electron microscopy. Phagocytosis assays showed high susceptibility of mutant Δcps14B. An in vivo murine model was used to demonstrate attenuated virulence of this non-encapsulated mutant. Despite the difference in the CPS composition of different serotypes, this study has demonstrated for the first time that the CPS of a serotype other than 2 is also an important antiphagocytic factor and a critical virulence factor.
Afficher plus [+] Moins [-]Prevalence of internal parasites in beef cows in the United States: Results of the National Animal Health Monitoring System’s (NAHMS) beef study, 2007‐2008
2015
Stromberg, Bert E. | Gasbarre, Louis C. | Ballweber, Lora R. | Dargatz, David A. | Rodriguez, Judith M. | Kopral, Christine A. | Zarlenga, Dante S.
During the United States Department of Agriculture (USDA) National Animal Health Monitoring System’s (NAHMS) 2007‐2008 beef study, 567 producers from 24 US States were offered the opportunity to collect fecal samples from weaned beef calves and have them evaluated for the presence of parasite eggs (Phase 1). Participating producers were provided with instructions and materials for sample collection. Up to 20 fresh fecal samples were collected from each of the 99 participating operations. Fresh fecal samples were submitted to one of 3 randomly assigned laboratories for evaluation. Upon arrival at the laboratories, all samples were processed for the enumeration of strongyle, Nematodirus, and Trichuris eggs using the modified Wisconsin technique. The presence or absence of coccidian oocysts and tapeworm eggs was also noted. In submissions where the strongyle eggs per gram exceeded 30, aliquots from 2 to 6 animals were pooled for DNA extraction. Extracted DNA was subjected to genus level polymerase chain reaction (PCR) identification for the presence of Ostertagia, Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. In this study, 85.6% of the samples had strongyle type, Nematodirus, and Trichuris eggs. Among the samples evaluated, 91% had Cooperia, 79% Ostertagia, 53% Haemonchus, 38% Oesophagostomum, 18% Nematodirus, 7% Trichuris, and 3% Trichostrongylus. The prevalence of coccidia and tapeworm eggs was 59.9% and 13.7%, respectively.
Afficher plus [+] Moins [-]Pharmacokinetics of pergolide after intravenous administration to horses
2015
OBJECTIVE To determine the pharmacokinetics of pergolide after IV administration to horses. ANIMALS 8 healthy adult horses. PROCEDURES Pergolide mesylate was administered IV at a dose of 20 μg/kg (equivalent to 15.2 μg of pergolide/kg) to each horse, and blood samples were collected over 48 hours. Pergolide concentrations in plasma were determined by means of high-performance liquid chromatography–tandem mass spectrometry, and pharmacokinetic parameters were determined on the basis of noncompartmental methods. RESULTS After IV administration of pergolide, mean ± SD clearance, elimination half-life, and initial volume of distribution were 959 ± 492 mL/h/kg, 5.64 ± 2.36 hours, and 0.79 ± 0.32 L/kg, respectively. CONCLUSIONS AND CLINICAL RELEVANCE With an elimination half-life of approximately 6 hours, twice-daily dosing may be more appropriate than once-daily dosing to reduce peak-trough fluctuation in pergolide concentrations. Further pharmacodynamic and pharmacokinetic studies of pergolide and its metabolites will be necessary to determine plasma concentrations that correlate with clinical effectiveness to determine the therapeutic range for the treatment of pituitary pars intermedia dysfunction.
Afficher plus [+] Moins [-]Evaluation of a ferret-specific formula for determining body surface area to improve chemotherapeutic dosing
2015
OBJECTIVE To use CT-derived measurements to create a ferret-specific formula for body surface area (BSA) to improve chemotherapeutic dosing. ANIMALS 25 adult ferrets (19 live and 6 cadavers). PROCEDURES Live subjects were weighed, and body measurements were obtained by each of 3 observers while ferrets were awake and anesthetized. Computed tomography was performed, and a 3-D surface model was constructed with open-source imaging software, from which BSA was estimated. The CT-derived values were compared with BSA calculated on the basis of the traditional tape method for 6 cadavers. To further validate CT analysis software, 11 geometric shapes were scanned and their CT-derived values compared with those calculated directly via geometric formulas. Agreement between methods of surface area estimation was assessed with linear regression. Ferret-specific formulas for BSA were determined with nonlinear regression models. RESULTS Repeatability among the 3 observers was good for all measurements, but some measurements differed significantly between awake and anesthetized ferrets. Excellent agreement was found between measured versus CT-derived surface area of shapes, traditional tape– versus CT-derived BSA of ferret cadavers, and CT-derived BSA of cadavers with and without monitoring equipment. All surface area formulas performed relatively similarly. CONCLUSIONS AND CLINICAL RELEVANCE CT-derived BSA measurements of ferrets obtained via open-source imaging software were reliable. On the basis of study results, the recommended formula for BSA in ferrets would be 9.94 × (body weight)2/3; however, this represented a relatively minor difference from the feline-derived formula currently used by most practitioners and would result in little practical change in drug doses.
Afficher plus [+] Moins [-]Attenuation of the pressor response to exogenous angiotensin by angiotensin receptor blockers and benazepril hydrochloride in clinically normal cats
2015
Jenkins, Tiffany L. | Coleman, Amanda E. | Schmiedt, Chad W. | Brown, Scott A.
OBJECTIVE To compare the attenuation of the angiotensin I–induced blood pressure response by once-daily oral administration of various doses of angiotensin receptor blockers (irbesartan, telmisartan, and losartan), benazepril hydrochloride, or lactose monohydrate (placebo) for 8 days in clinically normal cats. ANIMALS 6 healthy cats (approx 17 months old) with surgically implanted arterial telemetric blood pressure–measuring catheters. PROCEDURES Cats were administered orally the placebo or each of the drug treatments (benazepril [2.5 mg/cat], irbesartan [6 and 10 mg/kg], telmisartan [0.5, 1, and 3 mg/kg], and losartan [2.5 mg/kg]) once daily for 8 days in a crossover study. Approximately 90 minutes after capsule administration on day 8, each cat was anesthetized and arterial blood pressure measurements were recorded before and after IV administration of each of 4 boluses of angiotensin I (20, 100, 500, and 1,000 ng/kg). This protocol was repeated 24 hours after benazepril treatment and telmisartan (3 mg/kg) treatment. Differences in the angiotensin I–induced change in systolic arterial blood pressure (ΔSBP) among treatments were determined. RESULTS At 90 minutes after capsule administration, only losartan did not significantly reduce ΔSBP in response to the 3 higher angiotensin doses, compared with placebo. Among drug treatments, telmisartan (3 mg/kg dosage) attenuated ΔSBP to a significantly greater degree than benazepril and all other treatments. At 24 hours, telmisartan was more effective than benazepril (mean ± SEM ΔSBP, 15.7 ± 1.9 mm Hg vs 55.9 ± 12.42 mm Hg, respectively). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that telmisartan administration may have advantages over benazepril administration for cats with renal or cardiovascular disease.
Afficher plus [+] Moins [-]Avian reovirus replication in mononuclear phagocytes in chicken footpad and spleen after footpad inoculation
2015
Chen, Yu San | Shen, Pin Chun | Su, Bor Sheu | Liu, Tsung Ching | Lin, Cheng Chung | Lee, Long Huw
Circulating monocytes and tissue macrophages were suggested to be susceptible to avian reovirus (ARV) infection. To determine if ARV infects and replicates in mononuclear phagocytes (KUL01-positive cells), we infected 3-day-old specific-pathogen-free chickens with ARV strain 2408 by inoculation of the left footpad. The left footpads and spleens were collected for analysis at 1.5 and 2.5 d after inoculation. Replication of ARV in the footpad and spleen was demonstrated by detection of the viral protein σNS using immunohistochemical testing and viral S1 RNA expression by real-time quantitative polymerase chain reaction (qPCR). Furthermore, immunofluorescent double-staining assay of cytocentrifuged cells and cryosections of the footpad and spleen for the viral protein σNS and the surface marker recognized by monoclonal antibody (MAb) KUL01 indicated that KUL01-positive cells costained with MAb H1E1, which recognizes ARV protein σNS. In addition, more ARV S1 RNA was measured by qPCR in the KUL01-positive cell samples prepared from the footpad or spleen 1.5 d after inoculation compared with non-KUL01-positive cell samples. The amounts of ARV S1 RNA in the spleen were significantly lower (P < 0.05) than the amounts in the footpad 1.5 d after inoculation. The results suggest that ARV infects mononuclear phagocytes and then replicates within these cells before migrating to the spleen, where it infects and replicates in KUL01-positive cells.
Afficher plus [+] Moins [-]