Animal Health Trust

Abstract An 11‐year‐old, female, spayed Shetland sheepdog was referred for a 48‐hour onset of lethargy, inappetence, pigmenturia and intra‐abdominal mass of unknown origin. Laboratory sampling identified regenerative anaemia, hyperbilirubinemia, hypercholesterolemia and elevated alanine transaminase and alkaline phosphatase. Bilirubinuria and haematuria were noted on urinalysis. Thoracic radiographs were unremarkable. Ultrasonographic examination identified free abdominal fluid and a heterogeneous mass associated with a medial liver lobe. Haemoabdomen was confirmed, and partial hepatectomy was performed. Histopathology identified neoplastic cells arranged in nests and rosettes. On immunohistochemistry, neoplastic cells were positive for neuron‐specific enolase and synaptophysin and negative for S100, chromogranin A and cytokeratin. Transmission electron microscopy revealed small round electrodense granules consistent with neuroendocrine granules. A final diagnosis of hepatic carcinoid was made. The dog received no adjuvant treatment. Re‐staging with conventional imaging was performed every 3 months. No local recurrence or metastatic disease was identified within a 21‐month follow‐up period.

BackgroundThe IV use of human immunoglobulin (hIVIG) in dogs with primary immune‐mediated hemolytic anemia (IMHA) has been described previously, but herein we describe the use of high‐dose IgM‐enriched hIVIG (Pentaglobin).Hypothesis/ObjectivesDogs treated with high‐dose Pentaglobin will experience shorter time to remission and hospital discharge and have decreased transfusion requirements compared to dogs receiving standard treatment alone.AnimalsFourteen client‐owned dogs diagnosed with primary IMHA at specialist referral hospitals in the United Kingdom.MethodsAll prospectively enrolled dogs received prednisolone, dexamethasone or both along with clopidogrel. Patients were randomized to receive Pentaglobin at 1 g/kg on up to 2 occasions, or to serve as controls. No additional immunosuppressive drugs were allowed within the first 7 days of treatment. Remission was defined as stable PCV for 24 hours followed by an increase in PCV.ResultsTen of 11 dogs from the treatment group and 2 of 3 dogs from the control group achieved remission and survived until hospital discharge. Survival and time to remission were not significantly different between groups. The volume of packed red blood cells transfused, normalized for body weight, was not significantly different between groups. Potential adverse reactions to Pentaglobin occurred in 2 dogs, but their clinical signs may have been related to the underlying disease.Conclusions and Clinical ImportanceTreatment with high‐dose Pentaglobin was well tolerated by dogs with primary IMHA but no significant advantage was found in this small study. Additional studies examining larger groups and subpopulations of dogs with primary IMHA associated with a poorer prognosis are warranted.

SummaryGenotype imputation using a reference panel that combines high-density array data and publicly available whole genome sequence consortium variant data is potentially a cost-effective method to increase the density of extant lower-density array datasets. In this study, three datasets (two Border Collie; one Italian Spinone) generated using a legacy array (Illumina CanineHD, 173 662 SNPs) were utilised to assess the feasibility and accuracy of this approach and to gather additional evidence for the efficacy of canine genotype imputation. The cosmopolitan reference panels used to impute genotypes comprised dogs of 158 breeds, mixed breed dogs, wolves and Chinese indigenous dogs, as well as breed-specific individuals genotyped using the Axiom Canine HD array. The two Border Collie reference panels comprised 808 individuals including 79 Border Collies and 426 326 or 426 332 SNPs; and the Italian Spinone reference panel comprised 807 individuals including 38 Italian Spinoni and 476 313 SNPs. A high accuracy for imputation was observed, with the lowest accuracy observed for one of the Border Collie datasets (mean R2 = 0.94) and the highest for the Italian Spinone dataset (mean R2 = 0.97). This study’s findings demonstrate that imputation of a legacy array study set using a reference panel comprising both breed-specific array data and multi-breed variant data derived from whole genomes is effective and accurate. The process of canine genotype imputation, using the valuable growing resource of publicly available canine genome variant datasets alongside breed-specific data, is described in detail to facilitate and encourage use of this technique in canine genetics.

Summary Background Reasons for abnormal behaviour during tacking‐up and mounting are poorly documented. Objectives To relate behavioural abnormalities during tacking‐up or mounting to epaxial muscle hypertonicity or pain, girth region hypersensitivity, ill‐fitting tack, rider position and balance, or equine musculoskeletal pain. Study design Prospective observational study; convenience sample of 193 horses. Methods The behaviour of horses in a stable or tied up was observed for ≥8 min before systematic palpation of the thoracolumbosacral and girth regions. Owners were asked to tack‐up and mount using their normal regime. A purpose‐designed protocol for assessment of behaviour during tacking‐up and mounting was applied. Lameness was evaluated in‐hand and during ridden exercise. Static and dynamic saddle‐fit were assessed. A static saddle‐fit score was the sum of any saddle‐fit abnormality. Rider position in the saddle, balance and size relative to the saddle were evaluated during ridden exercise. Multivariable negative binomial regression modelling was used to assess the relationship between the sum of tacking‐up and mounting behaviours and horse, rider and tack‐fit variables. Results Riding School horses comprised only 12% of the sample population, but had higher rates of abnormal behaviours during both tacking‐up (P<0.0001) and mounting (P = 0.007) compared with General Purpose horses. The rate of abnormal behaviour during tacking‐up for horses with moderate or severe lameness was 1.4 times higher (P = 0.02) than for nonlame horses. Horses with lameness in‐hand or ridden had 1.5 times higher rates of abnormal behaviour during mounting than nonlame horses. Tight tree points (P = 0.03) and epaxial muscle pain (P<0.001) were associated with higher behaviour scores during tacking‐up. Higher static saddle‐fit scores were associated with higher behaviour scores during mounting. Main limitations Oral examination was not performed. Conclusions The display of many behaviours during tacking‐up or mounting is likely to reflect lameness or tack‐associated discomfort. Owners must be better educated to recognise these behaviours.

BackgroundRadiation therapy is commonly used as an adjunct to incomplete surgical excision in dogs with mast cell tumors (MCT), but the optimal dose and fractionation regimen have yet to be determined.HypothesisWe assessed outcomes (time to local recurrence, patient survival and toxicity) of a large population of dogs with MCT that received adjunctive radiation therapy.AnimalsThree hundred dogs with 302 MCT treated using adjunctive radiation therapy.MethodsRetrospective observational study. Clinical records of 4 veterinary radiation centers were reviewed.ResultsLocal recurrence rates were similar regardless of radiation protocol with 6.6% of patients developing recurrent cutaneous MCT at a median of 526 days. Local recurrence rate was similar between high and low‐risk MCT. Mast cell tumor related death was reported in 19% of all dogs, with 13% of dogs with low‐risk MCT dying of their disease compared to 29% of dogs with high‐risk MCT. No SC MCT (SCMCT) recurred after radiation therapy and only 7% of dogs with SCMCT were reported to have died of their disease. Mild late toxicity was common in both protocols and severe late toxicity occurred in 1.9% of dogs many years after treatment.Conclusions and Clinical ImportanceOur study supports the use of adjunctive radiation for the long‐term control of incompletely or narrowly excised cutaneous and SCMCT in dogs. More moderate dose and fractionation protocols may be appropriate in the adjunctive treatment of low‐risk MCT in dogs. Large multicenter prospective studies are required to establish the optimal dose and fractionation for MCT of different risk categories.

To identify temporal changes in antimicrobial resistance of ocular surface bacteria isolated from clinically symptomatic equine eyes in the South West of the UK. Retrospective. Clinical and laboratory records of horses treated for suspected bacterial ocular surface disease (ulcerative and non-ulcerative) at a single facility between January 2011 and December 2019 were reviewed. Cases were included if they underwent ocular surface sampling, aerobic bacterial culture, and antimicrobial susceptibility testing. Cases were split into two time periods based on when sampling occurred: "early" (2012-2015) and "late" (2016-2019) to enable identification of temporal trends in resistance to chloramphenicol, gentamicin, fusidic acid, neomycin, cloxacillin, ofloxacin, and polymyxin B. A total of 125 samples from 110 horses were included in analyses. Culture-positive isolates were identified in 76/110 (60.8%) samples. Principal isolates included Staphylococci spp. (n=45; 64.3%), Streptococcispp. (n=14; 20%), and Enterobacterspp. (n=11; 15.7%). There was a significant increase in resistance to chloramphenicol over time (P=.007) and a decrease in resistance to ofloxacin that approached significance (P=.059). Chloramphenicol (100%) and gentamicin (85.7%) had the highest overall in-vitro efficacy during the early and late periods, respectively. There was no significant difference in the type of bacteria isolated across the two time periods. These results suggest a potential increase in resistance to chloramphenicol among bacteria isolated from the ocular surface of horses in the South West UK, reinforcing the value of surveillance to guide the empirical use of antimicrobials.

Streptococcus agalactiae (group B streptococcus, or GBS) is a common cause of bacteremia and sepsis in newborns, pregnant women, and immunocompromised patients. The molecular mechanisms used by GBS to survive and proliferate in blood are not well understood. Here, using a highly virulent GBS strain and transposon-directed insertion site sequencing (TraDIS), we performed genome-wide screens to discover novel GBS genes required for bacterial survival in human whole blood and plasma. The screen identified 85 and 41 genes that are required for GBS growth in whole blood and plasma, respectively. A common set of 29 genes was required in both whole blood and plasma. Targeted gene deletion confirmed that (i) genes encoding methionine transporter (metP) and manganese transporter (mtsA) are crucial for GBS survival in whole blood and plasma, (ii) gene W903_1820, encoding a small multidrug export family protein, contributes significantly to GBS survival in whole blood, (iii) the shikimate pathway gene aroA is essential for GBS growth in whole blood and plasma, and (iv) deletion of srr1, encoding a fibrinogen-binding adhesin, increases GBS survival in whole blood. Our findings provide new insight into the GBS-host interactions in human blood.