Untreated abattoir effluent constitutes potential reservoir for transmission of pathogenic strains of multiple antibiotic-resistant bacteria by pollution of surface and ground water sources. This study was carried out to determine the antibiotic resistance and extended spectrum β-lactamase (ESBL) production profiles of Gram-negative bacteria isolated from effluent collected from Lafenwa municipal abattoir and its receiving surface water, Ogun River, in Abeokuta, Ogun state, Nigeria. Twelve effluent and 18 water samples were collected for this study. Total heterotrophic and coliform counts were estimated, bacterial identification was performed using standard culture-based procedures, whilst antibiotic resistance profiles of isolated bacteria against five antibiotics (ceftazidime, cefpodoxime, cefotaxime, ertapenem and amoxicillin-clavulanate) and detection of ESBLs were done using disk diffusion and double-disc synergy tests. A total of 54 Gram-negative bacteria were isolated, including Salmonella spp. (9), Escherichia coli (15), Klebsiella spp. (7), Shigella spp. (5), Pseudomonas spp. (12) and Enterobacter spp. (6). Both Enterobacteriaceae and Pseudomonas isolates (31% and 66.6%, respectively) were resistant to all selected antibiotics except ertapenem (98% susceptibility). Overall, 77% isolates had multiple antibiotic resistance index (MARI) values, but none of the antibiotic-resistant isolates showed evidence of ESBL production. The presence of multiple antibiotic-resistant isolates in the effluent and receiving water of Lafenwa abattoir suggests a major risk to public health and food safety. Current methods of waste disposal at the abattoir are unacceptable and greatly reduce the qualities of the processed meat and contaminate the environment. There is a need for improved abattoir waste management and water treatment strategies.

Listeria monocytogenes is a zoonotic food-borne pathogen that is associated with serious public health and economic implications. In animals, L. monocytogenes can be associated with clinical listeriosis, which is characterised by symptoms such as abortion, encephalitis and septicaemia. In human beings, listeriosis symptoms include encephalitis, septicaemia and meningitis. In addition, listeriosis may cause gastroenteric symptoms in human beings and still births or spontaneous abortions in pregnant women. In the last few years, a number of reported outbreaks and sporadic cases associated with consumption of contaminated meat and meat products with L. monocytogenes have increased in developing countries. A variety of virulence factors play a role in the pathogenicity of L. monocytogenes. This zoonotic pathogen can be diagnosed using both classical microbiological techniques and molecular-based methods. There is limited information about L. monocytogenes recovered from meat and meat products in African countries. This review strives to: (1) provide information on prevalence and control measures of L. monocytogenes along the meat value chain, (2) describe the epidemiology of L. monocytogenes (3) provide an overview of different methods for detection and typing of L. monocytogenes for epidemiological, regulatory and trading purposes and (4) discuss the pathogenicity, virulence traits and antimicrobial resistance profiles of L. monocytogenes.

OBJECTIVE To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica). ANIMALS 12 adult orange-winged Amazon parrots (6 males and 6 females). PROCEDURES A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography–mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis. RESULTS Mean ± SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 ± 186 ng/mL, 3.8 ± 1.8 hours, 23.2 ± 2.9 hours, and 38.6 ± 7.4 μg·h/mL, respectively, after a single dose and 1,185 ± 270 ng/mL, 3.0 ± 2.4 hours, 21.5 ± 5.3 hours, and 26.3 ± 5.7 μg·h/mL, respectively, at steady state after multiple doses. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.

The objective of this study was to evaluate the efficacy of a modified-live virus (MLV) porcine reproductive and respiratory syndrome virus (PRRSV) vaccine against a heterologous PRRSV-2 challenge in late-term pregnancy gilts under experimental conditions. Eighteen gilts were randomly assigned to vaccinated-challenged, unvaccinated-challenged, and unvaccinated-unchallenged groups (n = 6 gilts per group). Pregnant gilts in the vaccinated-challenged and unvaccinated-unchallenged groups were able to carry their pregnancies to full term and farrowed after 114 to 115 days of gestation. In contrast, pregnant gilts in the unvaccinated-challenged group did not reach full term and farrowed early, after 104 to 108 days of gestation. Pregnant gilts vaccinated with the PRRSV-2 MLV vaccine exhibited a reduction in PRRSV-2 viremia. At the time of challenge with PRRSV-2, vaccinated gilts had relatively low levels of neutralizing antibody titers (≤ 1:16 titer), whereas the number of interferon-γ-secreting cells (IFN-γ-SC) was consistently at protective levels (IFN-γ-SC, ≥ 150 per million). Induction of cell-mediated immunity, as measured by PRRSV-2-specific IFN-γ-SC, correlated with a reduction in PRRSV-2 viremia. Duration of immunity was a minimum of 19 wk. Taken together, the results presented here suggest that vaccination of gilts with a PRRSV-2 MLV vaccine can protect against a heterologous PRRSV-2 challenge and improve the reproductive performance of late-term pregnancy gilts.

OBJECTIVE To compare the efficacy and duration of desensitization of oral structures following injection of various volumes of lidocaine-bupivacaine via an infraorbital approach in dogs. ANIMALS 6 healthy adult hound-type dogs. PROCEDURES In a randomized crossover study, each dog received 1, 2, and 3 mL of a 2% lidocaine-0.5% bupivacaine mixture (50:50 vol/vol) injected within and near the caudal aspect of the infraorbital canal with a 14-day washout period between treatments. Dogs were anesthetized, and each treatment was administered through a 22-gauge, 4.5-cm-long catheter, which was fully inserted through and then withdrawn 2 cm to the caudal aspect of the infraorbital canal. The reflex-evoked motor potential was measured for the maxillary canine tooth (MC), fourth premolar tooth (MPM4), second molar tooth (MM2), and hard palate mucosa ipsilateral to the injected treatment and for the contralateral MC (control) at predetermined times before and for 6 hours after treatment administration or until the block was no longer effective. For each oral structure, the proportion of dogs with desensitization (efficacy) and time to onset and duration of desensitization were compared among the 3 treatments (injectate volumes). RESULTS Treatment was not associated with efficacy, time to onset, or duration of desensitization. Regardless of treatment, MC and MPM4 were more frequently desensitized and mean durations of desensitization for MC and MPM4 were longer, compared with those for MM2 and the hard palate. CONCLUSIONS AND CLINICAL RELEVANCE the volume of local anesthetic used for an infraorbital nerve block had no effect on block efficacy or duration.

OBJECTIVE To establish a method for evaluation of the efficacy of a classical swine fever virus (CSFV) subunit vaccine in rabbits as determined via humoral immune responses to the virus. ANIMALS 40 specific pathogen–free rabbits. PROCEDURES Rabbits were randomly assigned to 4 groups (10 rabbits/group) for SC injection of 0.05, 0.1, and 0.2 mL of a CSFV subunit E2 vaccine (representing 1.15, 2.3, or 4.6 μg of E2 protein/dose, respectively) or saline (0.9% NaCl) solution. Blood samples were collected 21 days after vaccination for measurement of the antibody response against CSFV via ELISA and virus neutralization methods. On the same day, the CSFV Chinese (C) strain was injected into an ear vein. Vaccine efficacy was determined by monitoring of rabbits for pyrexia for 4 days and measurement of viral copies in spleen lysates at the end of the study. Reproducibility of the antibody response was tested with 2 other batches of the vaccine at the minimum immunization dose identified for the initially tested batch. RESULTS The E2 protein dose of the initially tested vaccine was positively correlated with the antibody response and protection rate in rabbits. The identified minimum immunization dose per rabbit was 0.1 mL, representing an E2 protein content of approximately 2.3 μg, and reproducibility of the antibody response to vaccination with the 2 other batches at this dose was good. CONCLUSIONS AND CLINICAL RELEVANCE A method was established in rabbits for evaluation of the efficacy of a CSFV subunit vaccine that could help in the optimization of later large-scale vaccine production and quality control processes as well as in the clinical application of the vaccine.

OBJECTIVE To investigate whether an actual improvement in gait could be differentiated from physiologic differences or habituation effects during gait analysis of dogs. ANIMALS 11 healthy dogs. PROCEDURES On 4 examination days, kinetic parameters were measured while dogs were walking on a treadmill. Differences in mean parameter values and habituation effects (ie, effect sizes) were quantified and compared among examination days. Coefficients of variation for repeated measurements were calculated to determine measurement reproducibility, and minimum differences were calculated to distinguish between physiologic fluctuation and an actual change in gait pattern. RESULTS Among the 4 examination days, mean absolute differences in peak vertical force and vertical impulse (VI) varied from 1.5% to 5.3% of body weight (BW) and 0.9% to 1.8% of BW·s, respectively. Mean absolute differences in the percentage of stance-phase duration (%SPD) and relative stride length (RSL) varied from 0.9% to 3.2% and 1.7% to 3.0%, respectively. Reproducibility of parameter measurements was good. Values for %SPD had the lowest amount of dispersion and largest effect size, suggesting a habituation effect for this parameter. Calculated minimum differences among the days for peak vertical force, VI, %SPD, and RSL did not exceed 9.9% of BW, 3.3% of BW·s, 5.8 percentage points, and 5.2 percentage points, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The %SPD of healthy dogs walking on a treadmill was the most sensitive and diagnostically reliable of the measured kinetic parameters, in contrast to VI and RSL. Findings suggested that actual changes can be distinguished from random physiologic fluctuations during gait analysis of dogs.

OBJECTIVE To characterize antimicrobial prescribing patterns of clinicians and clinical services at a large animal veterinary teaching hospital and identify factors associated with antimicrobial prescribing. ANIMALS All large animals (ie, equids, bovids, sheep, goats, camelids, swine, and cervids) evaluated at the New Bolton Center hospital at the University of Pennsylvania from 2013 through 2018. PROCEDURES In a cross-sectional study design, data on antimicrobial use by clinicians and clinical services were collected from administrative and billing records. Multivariable regression modeling was performed to identify factors associated with antimicrobial prescribing patterns. RESULTS Antimicrobials and critically important antimicrobials of the highest priority were dispensed in 42.1% (9,853/23,428) and 24.0% (2,360/9,853) of visits, respectively, and these proportions differed significantly among clinicians. Per visit, the median (interquartile [25th to 75th percentile] range) number of animal-defined daily doses dispensed was 3.6 (0.8 to 11.1) and the mean (SD) number of antimicrobial classes dispensed was 2.0 (1.3). Patient species, age, affected body system, and duration of hospitalization as well as submission of specimens for bacterial culture were significantly associated with prescribing patterns. CONCLUSIONS AND CLINICAL RELEVANCE The frequency and quantity of antimicrobials prescribed differed significantly among clinicians within and across services, even for animals with clinical signs affecting the same body system. Patient- and visit-level factors explained some but not all of the heterogeneity in prescribing patterns, suggesting that other clinician-specific factors drove such practices. More research is needed to better understand antimicrobial prescribing patterns of clinicians, particularly in situations for which no antimicrobial use guidelines have been established.

OBJECTIVE To determine the optimal energy profile for and to assess the feasibility and efficacy of ultrasonographic and laparoscopic guidance for microwave ablation (MWA) of clinically normal canine ovaries. SAMPLE 44 extirpated ovaries from 22 healthy dogs. PROCEDURES In the first of 2 trials, 13 dogs underwent oophorectomy by routine laparotomy. Extirpated ovaries underwent MWA at 45 W for 60 (n = 11) or 90 (12) seconds; 3 ovaries did not undergo MWA and served as histologic controls. Ovaries were histologically evaluated for cell viability. Ovaries without viable cells were categorized as completely ablated. Histologic results were used to identify the optimal MWA protocol for use in the subsequent trial. In the second trial, the ovaries of 9 dogs underwent MWA at 45 W for 90 seconds in situ. Ultrasonographic guidance for MWA was deemed unfeasible after evaluation of 1 ovary. The remaining 17 ovaries underwent MWA with laparoscopic guidance, after which routine laparoscopic oophorectomy was performed. Completeness of ablation was histologically assessed for all ovaries. RESULTS 2 ovaries were excluded from the trial 1 analysis because of equivocal cell viability. Six of 11 ovaries and 10 of 10 ovaries that underwent MWA for 60 and 90 seconds, respectively, were completely ablated. In trial 2, laparoscopic-guided MWA resulted in complete ablation for 12 of 17 ovaries. Dissection of the ovarian bursa for MWA probe placement facilitated complete ablation. CONCLUSIONS AND CLINICAL RELEVANCE Laparoscopic-guided MWA at 45 W for 90 seconds was feasible, safe, and effective for complete ablation of clinically normal ovaries in dogs.

OBJECTIVE To evaluate holding security of 4 friction knots created with various monofilament and multifilament sutures in a vascular ligation model. SAMPLE 280 friction knot constructs. PROCEDURES 10 friction knots of 4 types (surgeon's throw, Miller knot, Ashley modification of the Miller knot, and strangle knot) created with 2-0 monofilament (polyglyconate, polydioxanone, poliglecaprone-25, and glycomer-631) and braided multifilament (silk, lactomer, and polyglactin-910) sutures were separately tied on a mock pedicle and pressure tested to the point of leakage. Linear regression analysis was performed to compare leakage pressures among suture materials (within friction knot type) and among knot types (within suture material). RESULTS Mean leakage pressure of surgeon's throws was significantly lower than that of all other knots tested, regardless of the suture material used. All the other knots had mean leakage pressures considered supraphysiological. Significant differences in mean leakage pressure were detected between various friction knots tied with the same type of suture and various suture types used to create a given knot. Variability in leakage pressure among knots other than the surgeon's throw was greatest for poliglecaprone-25 and lowest for polydioxanone. CONCLUSIONS AND CLINICAL RELEVANCE Most differences in knot security, although statistically significant, may not have been clinically relevant. However, results of these in vitro tests suggested the surgeon's throw should be avoided as a first throw for pedicle ligation and that poliglecaprone-25 may be more prone to friction knot slippage than the other suture materials evaluated.