American journal of veterinary research最新文献

Objective: To assess the agreement of transpulmonary thermodilution (TPTD) and transpulmonary ultrasound dilution (TPUD) against direct measurement of main pulmonary artery flow with an ultrasound transit time flow probe (UTF) over a wide range of conditions in anesthetized cats. Additionally, the trending ability of TPTD, TPUD, and esophageal Doppler ultrasonography (EDU) was evaluated against UTF.

Methods: 12 purpose-bred cats were used. One cat was used for a pilot study. The cats were instrumented according to the manufacturer's recommendation. Paired measurements were made over a wide range of cardiac output. Agreement was analyzed with Bland-Altman analysis with repeated measures, and trending ability was assessed by 4-quadrant plot and concordance rate. Interchangeable was defined as percentage error less than simplified total error. Acceptable trending was defined as concordance rate > 95%.

Results: Bias and percentage error were -0.084 L·min-1 and 38.2% for TPTD and -0.041 L·min-1 and 52.9% for TPUD. The concordance rate was 100%, 95.5%, and 64% to 65% for TPTD, TPUD, and EDU, respectively.

Conclusions: Both TPTD and TPUD were not interchangeable to UTF. Both TPTD and TPUD provided acceptable trending ability but not EDU.

Clinical relevance: Transpulmonary thermodilution and TPUD allow detection of the direction of cardiac output changes in anesthetized cats but not EDU. Clinical and research use of these 3 devices warrants careful consideration of the limitations presented in this study.

Objective: To determine the predictive potential of the open reading frame 5 nucleotide sequence of porcine reproductive and respiratory syndrome (PRRS) virus and the basic demographic data on the severity of the impact on selected production parameters during clinical PRRS outbreaks in Ontario sow herds.

Methods: A retrospective longitudinal study of clinical outbreaks in Ontario sow herds at various points between September 5, 2009, and February 5, 2019, was conducted using herds as units of analysis. Data were gathered from study sow farms in Ontario at the start of each clinical outbreak. Six machine learning models and 2 different genetic input structures of open reading frame 5 sequences were utilized to predict the impact on abortion and preweaning mortality.

Results: Extreme boosting machine learning models with genetic data represented through 2-dimensional multiple correspondence analysis had the highest accuracy when predicting clinical outcomes (60.8% [SD = 12.4%] and 74.4% [SD = 13.2%]) for abortion and preweaning mortality outcomes, respectively. The mean sensitivity of classifying outbreaks with a high impact on abortion was 50%, with a specificity of 89.2%. The mean sensitivity of classifying outbreaks with high preweaning mortality was 56.2%, with a specificity of 85.2%.

Conclusions: The data and methods utilized herein exhibited improvement in accuracy over the baseline; however, this increase was not sufficient to warrant field implementation.

Clinical relevance: Predictive models based on observed data could assist practitioners in linking the genetics of the PRRS virus with clinical impact in clinical settings. Models trained in this study show promise for PRRS clinical impact prediction.

Objective: To understand the prevalence, genetic diversity, and potential pathogenicity of adenoviruses present in pigeon and turtledove populations.

Methods: Nested PCR and Sanger sequencing methods were used to identify the genotype and percentage of various adenoviruses in the feces of pigeon (Columba) and turtledove (Streptopelia) populations. In Beijing, China, a total of 194 fresh feces samples from meat-use pigeons (C livia domestica), homing pigeons (C livia domestica), wild pigeons (C livia domestica), and turtledoves (S decaocto and S chinensis) were collected using noninvasive sampling collection techniques. Their partial DNA-dependent DNA polymerase gene sequences were obtained using nested PCR and double-ended Sanger sequencing, and their genotypes were then ascertained based on sequence alignment.

Results: A total of 6 genotypes of adenovirus were detected in pigeon and turtledove flocks, including pigeon adenovirus (PiAdV)-1, PiAdV-2A, PiAdV-3, PiAdV-4, PiAdV-5, and a novel adenovirus genotype (PiAdV-6). Among them, PiAdV-1 was found widespread in flocks of pigeons exhibiting extensive presentations of hepatic necrosis. Highly conserved PiAdV-4 and PiAdV-5 were found to be nonpathogenic and extensively distributed in all pigeon and turtledove groups.

Conclusions: These findings imply the presence of diverse PiAdVs in pigeon and turtledove flocks, and the wild pigeons and wild turtledove birds are potentially serving as natural sources of these viruses.

Clinical relevance: This study provides supportive evidence of the pathogenicity of different genotypes of adenovirus in pigeon flocks and also implies that stopping the transmission of the virus brought by wild pigeons and turtledoves may be important for the prevention of diseases associated with PiAdVs.

Objective: To compare the pharmacokinetics of cannabidiol (CBD) and cannabidiolic acid (CBDA) in horses and to evaluate the safety of their chronic administration.

Methods: CBD- and CBDA-rich oil (1 mg/kg) were administered orally twice daily to 7 adult horses over 6 weeks in a randomized, crossover design with a 2-week washout period. A 12-hour pharmacokinetic analysis was conducted on day 1 of each 6-week trial, followed by the measurement of peak and trough concentrations at weeks 1, 2, 4, and 6. The cannabinoids safety was assessed via daily physical examination, periodic bloodwork, and liver biopsy at the beginning and end of the study.

Results: 12-hour pharmacokinetics revealed a higher maximum serum concentration (103 vs 12 ng/mL) and greater area under the curve (259 vs 62 ng·h/mL) for CBDA when compared to CBD. Cannabidiolic acid nadir and peak serum levels over time ranged from 46 to 122 ng/mL, which was higher than CBD (12 to 38 ng/mL). Complete blood count and serum chemistry revealed no clinically relevant changes with either CBD or CBDA. No significant abnormalities were detected on liver ultrasonographic and histopathologic evaluation on day 0 and after both phases of the study.

Conclusions: A dose of either 1 mg/kg of CBD or CBDA administered long term appears safe; however, CBDA serum concentrations suggest superior absorption/retention.

Clinical relevance: Chronic cannabinoid supplementation in horses is safe. Considering the higher absorption of CBDA, its use is recommended to evaluate the therapeutic efficacy of this common hemp derived cannabinoid.

Objective: In severe equine asthma, structural remodeling of the airways ultimately leads to bronchial wall thickening and airflow obstruction. Increased bronchial vascularization has been described in horses affected by the severe form of the disease, but whether it contributes to bronchial remodeling in milder forms of asthma remains to be determined. In a blinded, retrospective case-control study, we evaluated the presence of bronchial angiogenesis in horses with mild and moderate equine asthma (MEA) and its correlation to airway smooth muscle remodeling.

Methods: Endobronchial biopsies from the Equine Respiratory Tissue Biobank collected between August 14, 2014, and May 31, 2019, from 9 horses with MEA and 7 healthy controls were studied. The vascular basement membrane was identified by immunohistochemistry, allowing the measurement of the number of bronchial vessels, vascular area, and mean vessel size by histomorphometry. The correlations between angiogenic parameters, airway smooth muscle (ASM) remodeling features, and airway neutrophilia were studied.

Results: No differences between groups were observed for the angiogenic parameters evaluated. The number of vessels was correlated to ASM cell proliferation in MEA horses (Spearman r = 0.73) but not in controls. Airway neutrophilia correlated negatively with mean vessel size in horses with MEA (Pearson r = -0.83) but not in control horses.

Conclusions: Major changes in bronchial vascularization do not occur in central airways in MEA.

Clinical relevance: Contrary to previous findings in horses with severe equine asthma, angiogenesis is not a prominent feature of MEA, but it might be associated with ASM remodeling.

Objective: To determine if oxidative stress induces phosphatidylserine (PS) externalization in canine erythrocytes and if exposure to antioxidants prevents such changes.

Methods: This was an in vitro, experimental study using 5 healthy, adult, purpose-bred research Beagles. Fresh EDTA-anticoagulated blood samples were collected from each dog, and erythrocytes were harvested. For objective 1, erythrocytes were exposed to the pro-oxidant agents tert-butyl hydroperoxide (TBHP) at 2, 3, or 4 mM or 2,2'-azobis(2-amidinopropane) dihydrochloride at 30, 40, or 50 mM. For objective 2, erythrocytes were exposed to 3 mM TBHP and the antioxidant N-acetylcysteine-amide (NACA) at various concentrations (0, 1, or 3 mM). Erythrocytes incubated with benzoylbenzoyl-ATP were used as positive control, whereas erythrocytes incubated with sodium chloride medium with 0.1% bovine serum albumin, DMSO, and NACA were used as negative controls. Erythrocytes were stained with allophycocyanin-conjugated Annexin V, and PS externalization was assessed by flow cytometry. The degree of PS externalization of each sample was recorded as median fluorescence intensity and percentage of PS positivity.

Results: TBHP at 3 and 4 mM caused increased PS externalization in canine erythrocytes. 2,2'-Azobis(2-amidinopropane) dihydrochloride at all concentrations caused increased PS externalization. N-acetylcysteine-amide at all concentrations prevented significant PS externalization measured by median fluorescence intensity and percentage of PS positivity from erythrocytes exposed to TBHP.

Conclusions: Oxidative stress causes PS externalization in canine erythrocytes, and NACA ameliorates this effect.

Clinical relevance: Future studies are needed to determine if increased PS externalization in erythrocytes occurs in dogs with immune-mediated hemolytic anemia and its role in promoting thromboembolism.

Objective: To describe the prevalence, clinical findings, lesions, and risk factors associated with chlamydial infections in free-ranging raptors presented to a university veterinary medical teaching hospital.

Methods: Medical records retrospectively searched for raptors admitted from January 1993 through April 2022 were tested for Chlamydia spp infections using quantitative PCR (qPCR), immunohistochemistry, culture, and sequencing. Findings were collected and analyzed. Multivariable logistic regression analyzed the association between Chlamydia spp infection status and risk factors, including age class, species, sex, and season of admission.

Results: The prevalence for cases that tested positive for Chlamydia spp on 1 or more diagnostic tests, including mucosal qPCR samples for Chlamydia spp, tissue PCR for C buteonis, and mucosal qPCR genotyped as C buteonis, was 1.9% (74 of 3,983). All positive cases were from the genus Buteo (n = 74). Juvenile birds and winter season had higher odds of infection. All birds were in poor body condition (n = 74), often with moderate-to-severe CBC and biochemistry abnormalities consistent with multiorgan chronic inflammatory disease, emaciation, and dehydration. On postmortem examination of Chlamydia-positive birds (58 of 74), hepatitis (44 of 56), nephritis (24 of 39), splenitis (22 of 53), airsacculitis (21 of 43), myocarditis (21 of 39), and pneumonia (21 of 38) were common lesions, with intracellular bacteria in multiple tissues.

Conclusions: Signalment, season of admission, clinical signs, clinicopathologic findings, and Chlamydia-specific testing identified chlamydial infections in free-ranging raptors. Appropriate protections to prevent potential zoonotic transmission in clinical wildlife rehabilitation settings are recommended.

Clinical relevance: Many clinical parameters used to identify C psittaci infection in parrots can also be used to identify chlamydial infections in raptors.

Objective: To describe immune responses following administration of experimental Salmonella Dublin siderophore receptor protein (SRP) vaccines in Holstein heifer calves with adequate passive antibody transfer.

Methods: Calves were randomly assigned to receive placebo, vaccination with S Dublin SRP in adjuvant A, or vaccination with S Dublin SRP in adjuvant B at 7 ± 3 days of age and 3 weeks later. Before each vaccination, 4 and 8 days after the second vaccination (postvaccination), and 61 to 91 days postvaccination, S Dublin antibody titers were measured. Blood mononuclear cells isolated from blood collected 4 and 8 days postvaccination were stimulated with S Dublin SRP antigen (1 or 5 µg/mL) or positive or negative controls, then analyzed to quantify S Dublin SRP-responsive cells. Cultures of blood mononuclear cells were similarly stimulated to quantify interferon-γ (IFN-γ)-producing and IL-17-producing cells. The trial spanned September 4, 2022, through January 15, 2023.

Results: 78 calves were enrolled. Vaccinates had significantly higher IFN-γ-producing cells and IFN-γ and IL-17 concentrations at 4 and 8 days postvaccination, except IFN-γ concentration at day 4 after stimulation with 1 µg/mL. Vaccinates also had higher S Dublin titers at 8 and 61 to 90 days postvaccination. No differences in health events were noted.

Conclusions: Vaccination can induce S Dublin SRP-specific humoral and cellular immune responses in Holstein heifer calves.

Clinical relevance: Vaccination with SRP vaccines resulted in immune responses that may help mitigate S Dublin infection. Further research is needed to determine whether vaccination will be protective against S Dublin challenge.