Porcine reproductive and respiratory syndrome (PRRS), which is caused by the PRRS virus (PRRSV), has resulted in large economic losses for the swine industry. The virus has shown remarkable genetic diversity since its discovery. In our study, we investigated mutation types in the evolution of PRRSV for both in vivo and in vitro passaging of the virus. Sequence alignment analysis demonstrated that the most common hypermutations expressed were A→G/U→C and G→A/C→U. The data provide a new theoretical basis for PRRSV evolution.

OBJECTIVE To evaluate the efficacy of maropitant and loperamide for the prevention and reduction of adverse gastrointestinal effects associated with administration of paclitaxel to dogs with cancer. ANIMALS 168 dogs with cancer. PROCEDURES The study comprised 2 phases. For phase 1, dogs in the intervention group were administered maropitant and loperamide followed by paclitaxel. Outcomes were compared with those for a control group that received only maropitant and paclitaxel. For phase 2, all dogs of phase 1 that did not receive maropitant and loperamide and that had adverse gastrointestinal effects were enrolled; they received maropitant and loperamide and another dose of paclitaxel. RESULTS In phase 1, significantly fewer dogs in the intervention group had adverse effects. For dogs that had adverse effects, the intervention group had a lower severity of lack of appetite and lethargy. Also, adverse effects for dogs in the intervention group were of significantly shorter duration than for the control group. In phase 2, significant reductions in adverse effects were observed after administration of maropitant and loperamide. In those dogs that still had adverse effects after administration of maropitant and loperamide, there was a significant reduction in severity of signs of nausea and lethargy. CONCLUSIONS AND CLINICAL RELEVANCE A combination of maropitant and loperamide was found to be safe for use and effective for reducing or preventing signs of paclitaxel-induced gastrointestinal effects in dogs.

Hantavirus is the causative agent of hemorrhagic fever with renal syndrome (HFRS). Heilongjiang Province is experiencing an epidemic of HFRS, the main causative agent is a variant of hantavirus called Seoul virus (SEOV). In this study, the entire genome of one SEOV, the DN2 strain, was sequenced and analyzed. The alignment analysis of the sequences indicated that the DN2 strain shares the highest homology with the SEOV-LYO852 strain. The nucleotide identity is 97.6% for the S segment, 97.7% for the M segment, and 98.0% for the L segment. The corresponding amino acid sequence homologies are 99.1%, 98.9% and 99.8%. The phylogenetic analysis of the segments suggests that the DN2 strain has a high genetic relationship with SEOV strains and no genetic recombination occurs.

Hemorrhagic pneumonia in mink is a fatal disease caused by Pseudomonas aeruginosa. Very little is known about P. aeruginosa in relation to genotype and the mechanisms underlying antimicrobial resistance in mink. A total of 110 P. aeruginosa samples were collected from mink from Chinese mink farms between 2007 and 2015. Samples underwent molecular genotyping using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), antimicrobial susceptibility and its mechanism were investigated at the molecular level. The PFGE identified 73 unique types and 15 clusters, while MLST identified 43 (7 new) sequence types (ST) and 12 sequence type clonal complexes (STCC). Sequence types and PFGE showed persistence of endemic clones in cities Wendeng (Shandong, China) and Dalian (Liaoning, China), even in different timelines. The MLST also revealed the gene correlation of the mink P. aeruginosa across different time and place. The ST1058 (n = 14), ST882 (n = 11), and ST2442 (n = 10) were the predominant types, among which ST1058 was the only one found both in Shandong province and Dalian (Liaoning, China). The MLST for P. aeruginosa infection in mink was highly associated with that in humans and other animals, implying possible transmission events. A small proportion of mink exhibited drug resistance to P. aeruginosa (9/69, 13%) with resistance predominantly to fluoroquinolone, aminoglycoside, and β-lactamase. Eight strains had mutations in the quinolone-resistance determining regions (QRDR). High proportions (65%; 72/110) of the fosA gene and 2 types of glpt deletion for fosmycin were detected. Furthermore, in the whole genome sequence of one multidrug resistant strain, we identified 27 genes that conferred resistance to 14 types of drugs.

OBJECTIVE To evaluate the elastic modulus of various ligaments of the forelimbs of cadaveric horses. SAMPLE 408 ligaments from 37 forelimbs of 10 Thoroughbred cadavers and cadavers of 9 other horse breeds. PROCEDURES Collateral ligaments and straight and oblique sesamoid ligaments were harvested from the proximal interphalangeal, metacarpophalangeal, carpal, and elbow joints of both forelimbs of all 19 horses. Ligament dimensions were measured, and the elastic modulus was determined by tensile testing the ligaments with a strain rate of 1 mm•s(-1). RESULTS Elastic modulus of the ligaments differed significantly among joints. Highest mean ± SE elastic modulus was for the medial collateral ligament of the metacarpophalangeal joints of Thoroughbreds (68.3 ± 11.0 MPa), and the lowest was for the lateral collateral ligament of the elbow joints of other breeds (2.8 ± 0.3 MPa). Thoroughbreds had a significantly higher elastic modulus for the collateral ligaments of the proximal interphalangeal and metacarpophalangeal joints, compared with values for the other breeds. There was large variation in elastic modulus. Elastic modulus was negatively affected by age. In the ligaments in the distal aspect of the forelimbs, elastic modulus was negatively affected by height at the highest point of the shoulders (ie, withers). CONCLUSIONS AND CLINICAL RELEVANCE Cross-sectional area and elastic modulus of collateral ligaments in the forelimbs of equine cadavers differed between breeds and among joints, which may have been reflective of their relative physiologic function under loading during exercise.

OBJECTIVE To evaluate the effect of contrast medium injection rate on CT-derived renal perfusion estimates obtained with the maximum slope method in healthy small dogs. ANIMALS 6 healthy sexually intact male purpose-bred Beagles. PROCEDURES All dogs underwent CT perfusion analysis 3 times in a crossover design, receiving a different contrast medium injection rate (1.5, 3.0, and 4.5 mL/s) each time, with a 1-week interval between imaging sessions. All CT images were obtained at the level of the left renal hilus. The time to peak aortic enhancement (TPAE) and time to initial renal venous enhancement (TIRVE) were measured from time-attenuation curves. The renal CT perfusion estimates (blood flow and blood volume) were estimated by use of the maximum slope method, which assumes no venous outflow of contrast medium during CT perfusion analysis. RESULTS The TPAE occurred at or before the TIRVE at all injection rates. Median values of estimated blood flow and blood volume did not differ significantly among injection rates. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the assumption of no venous outflow of contrast medium during renal CT perfusion analysis with the maximum slope method was satisfied for all 3 contrast medium injection rates in the evaluated dogs. A low injection rate may be more practical than higher injection rates that require large catheters for CT perfusion analysis in small dogs such as Beagles.

OBJECTIVE To determine the pharmacokinetics and adverse effects of maropitant citrate after IV and SC administration to New Zealand White rabbits (Oryctolagus cuniculus). ANIMALS 11 sexually intact (3 males and 8 females) adult rabbits. PROCEDURES Each rabbit received maropitant citrate (1 mg/kg) IV or SC. Blood samples were collected at 9 (SC) or 10 (IV) time points over 48 hours. After a 2-week washout period, rabbits received maropitant by the alternate administration route. Pharmacokinetic parameters were calculated. Body weight, food and water consumption, injection site, mentation, and urine and fecal output were monitored. RESULTS Mean ± SD maximum concentration after SC administration was 14.4 ± 10.9 ng/mL and was detected at 1.25 ± 0.89 hours. Terminal half-life after IV and SC administration was 10.4 ± 1.6 hours and 13.1 ± 2.44 hours, respectively. Bioavailability after SC administration was 58.9 ± 13.3%. Plasma concentration at 24 hours was 2.87 ± 1.69 ng/mL after IV administration and 3.4 ± 1.2 ng/mL after SC administration. Four rabbits developed local dermal reactions at the injection site after SC injection. Increased fecal production was detected on the day of treatment and 1 day after treatment. CONCLUSIONS AND CLINICAL RELEVANCE Plasma concentrations of rabbits 24 hours after SC and IV administration of maropitant citrate (1 mg/kg) were similar to those of dogs at 24 hours. Reactions at the SC injection site were the most common adverse effect detected. Increased fecal output may suggest an effect on gastrointestinal motility. Additional pharmacodynamic and multidose studies are needed.

OBJECTIVE To evaluate repeatability and reproducibility of muscle condition score (MCS) in dogs with various degrees of muscle loss; to compare MCS, muscle ultrasonographic measurements, and quantitative magnetic resonance (QMR) measurements; and to identify cutoff values for ultrasonographic measurements of muscle that can be used to identify dogs with cachexia and sarcopenia. ANIMALS 40 dogs of various age, body condition score (BCS), and MCS. PROCEDURES A prospective cross-sectional study was conducted. Body weight, BCS, QMR measurements, thoracic radiographic measurements, and muscle ultrasonographic measurements were assessed once in each dog. The MCS for each dog was assessed 3 separate times by 4 separate raters. RESULTS For the MCS, overall κ for interrater agreement was 0.50 and overall κ for intrarater agreement ranged from 0.59 to 0.77. For both interrater and intrarater agreement, κ coefficients were higher for dogs with normal muscle mass and severe muscle loss and lower for dogs with mild and moderate muscle loss. The MCS was significantly correlated with age (r = −0.62), vertebral epaxial muscle score (VEMS; r = 0.71), forelimb epaxial muscle score (FLEMS; r = 0.58), and BCS (r = 0.73), and VEMS was significantly correlated (r = 0.84) with FLEMS. Cutoff values for identification of mild muscle loss determined by use of VEMS and FLEMS were 1.124 and 1.666, respectively. CONCLUSIONS AND CLINICAL RELEVANCE MCS had substantial repeatability and moderate reproducibility for assessment of muscle mass in dogs. Prospective studies of MCS, VEMS, and FLEMS for assessment of muscle mass in dogs are warranted.

OBJECTIVE To compare the effects of a dexmedetomidine-ketamine-midazolam (DKM) anesthetic protocol versus isoflurane inhalation anesthesia on echocardiographic variables and plasma cardiac troponin 1 (cTnI) concentration in black-tailed prairie dogs (BTPDs; Cynomys ludovicianus). ANIMALS Nine 6-month-old sexually intact male captive BTPDs. PROCEDURES Each BTPD was randomly assigned to be anesthetized by IM administration of dexmedetomidine (0.25 mg/kg), ketamine (40 mg/kg), and midazolam (1.5 mg/kg) or via inhalation of isoflurane and oxygen. Three days later, each BTPD underwent the alternative anesthetic protocol. Echocardiographic data and a blood sample were collected within 5 minutes after initiation and just prior to cessation of each 45-minute-long anesthetic episode. RESULTS Time or anesthetic protocol had no significant effect on echocardiographic variables. For either protocol, plasma cTnI concentration did not differ with time. When administered as the first treatment, neither anesthetic protocol significantly affected plasma cTnI concentration. However, with regard to findings for the second treatments, plasma cTnI concentrations in isoflurane-treated BTPDs (n = 4; data for 1 animal were not analyzed because of procedural problems) were higher than values in DKM-treated BTPDs (4), which was suspected to be a carryover effect from prior DKM treatment. CONCLUSIONS AND CLINICAL RELEVANCE The DKM and isoflurane anesthetic protocols did not have any significant effect on echocardiographic measurements in the BTPDs. Increases in plasma cTnI concentration during the second anesthetic episode were evident when BTPDs underwent the DKM anesthetic protocol as the first of the 2 treatments, suggestive of potential myocardial injury associated with that anesthetic protocol. Clinicians should consider these findings, especially when evaluating BTPDs with known or suspected cardiac disease.

High-intensity exercise can be associated with the occurrence of muscle injury, as well as the induction of an acute-phase response (APR). The present study aims to investigate the synthesis and profile of serum proteins in horses before and after participating in 2 different exercise protocols and to relate this profile to the presence or absence of muscular injury caused by exercise. Ten purebred Arabian (n = 5) and Criollo (n = 5) horses were subjected to 2 different tests on a treadmill, one consisting of short-duration and rapid-acceleration training (TRA) that was mostly anerobic and the other of long-duration and slow-acceleration training (TLD) that was predominantly aerobic. Blood samples were obtained before the beginning of exercise (T0) and at 6 post-exercise time points: immediately after (T1) and 30 min (T2), 3 h (T3), 12 h (T4), 24 h (T5), and 48 h (T6) after exercise. Hematocrit was determined by the microhematocrit method. Plasma and serum samples were prepared by centrifugation (1500 × g for 5 min) for plasma concentrations of fibrinogen, total serum proteins (TP), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and creatine-kinase (CK) serum activity. Total protein concentration and CK serum activity were determined in an automated biochemistry analyzer. Fibrinogen was determined by the heat precipitation method in microhematocrit capillary tubes. Estimated concentrations of haptoglobin (Hp) significantly decreased after TRA and estimated concentrations of alpha-1 acid glycoprotein (AGP) significantly increased after both protocols at T2. Albumin increased after the TLD exercise protocol. Changes in hematocrit, haptoglobin, and albumin concentrations in horses subjected to different treadmill exercise protocols are related to a physiological response to hemoconcentration and hemolysis. Increases of AGP in the TLD protocol suggest the release of catecholamines as a response to avoid oxidative damage to tissue.