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Norway rats (Rattus norvegicus) inhabit cities worldwide and live in close association with humans. Studies of urban rat zoonoses often rely on live-trapping, with fewer studies using rats sourced through lethal pest control interventions. Our objectives were to evaluate the utility of rats collected by pest control professionals for zoonotic pathogen surveillance and determine whether we could detect Leptospira interrogans and Streptobacillus moniliformis in pest control sourced rats. Rat carcasses were submitted from Windsor, Canada by pest control professionals between November 2018 and March 2020. Submissions were categorized by season and land use. Necropsies were performed to classify carcass quality, collect tissue samples, and record demographic data. The association between carcass quality and the ability to collect tissue samples for pathogen surveillance was assessed via an exact logistic regression model. Using PCR, a subset of kidney and spleen samples were tested for L. interrogans and S. moniliformis, respectively. Our sample of pest control sourced rats had similar sex and age distributions to those of live-trapping studies. Rats were primarily submitted from residential and industrial locations during fall, winter, and spring, which may reflect pest control service areas and peak business periods, rather than rat distribution. Of 124 submissions, 98 (79.0%) of rats showed only mild decomposition. The odds of collecting all tissue samples were reduced for fair compared to good-quality carcasses (OR: 0.029; 95% CI: 0-0.25; p = .0009) and for poor compared to fair-quality carcasses (OR: 0.048; 95% CI: 0.00085-0.53; p = .0065). Leptospira interrogans and S. moniliformis were detected in 9.1% (4/44) and 27.3% (15/55) of a subset of rats tested, respectively. Our results suggest that pest control sourced rats are suitable for surveillance for multiple zoonotic pathogens in urban environments. This method of rat collection may provide preliminary information to guide more detailed ecological studies.

Objectives The aim of this study was to evaluate initial antimicrobial therapy in cats diagnosed with upper or lower bacterial urinary tract infections at veterinary practices in the USA and Canada. Methods Electronic medical records from a veterinary practice corporation with clinics in the USA and Canada were queried between 2 January 2016 and 3 December 2018. Feline patient visits with a diagnosis field entry of urinary tract infection, cystitis and pyelonephritis, as well as variation of those names and more colloquial diagnoses such as kidney and bladder infection, and where an antimicrobial was prescribed, were retrieved. Results Prescription data for 5724 visits were identified. Sporadic cystitis was the most common diagnosis (n = 5051 [88%]), with 491 (8.6%) cats diagnosed with pyelonephritis and 182 (3.2%) with chronic or recurrent cystitis. Cefovecin was the most commonly prescribed antimicrobial for all conditions, followed by amoxicillin–clavulanic acid. Significant differences in antimicrobial drug class prescribing were noted between practice types and countries, and over the 3-year study period. For sporadic cystitis, prescription of amoxicillin–clavulanic acid increased significantly and cefovecin decreased between 2016 and 2018, and 2017 and 2018, while fluoroquinolone use increased between 2017 and 2018. Conclusions and relevance The results indicate targets for intervention and some encouraging trends. Understanding how antimicrobials are used is a key component of antimicrobial stewardship and is required to establish benchmarks, identify areas for improvement, aid in the development of interventions and evaluate the impact of interventions or other changes.

Objectives The aims of this study were to determine the magnitude and duration of fecal viral DNA shedding after diagnosis of feline panleukopenia (FP) in a group of shelter cats using quantitative real-time PCR (qPCR); to assess the utility of a negative point-of-care test or the resolution of diarrhea and systemic signs as proxy measures for qPCR positivity; and to investigate patterns of additional enteric pathogens in relation to feline panleukopenia viral shedding duration. Methods Feline panleukopenia virus (FPV) infection in clinically affected shelter cats was confirmed by a commercial qPCR test. Observations were made on days 0, 3, 7, 14 and 21 post-diagnosis. Fecal flotation, FPV qPCR and the canine parvovirus IDEXX SNAP Parvo ELISA (SNAP) test were performed on fecal samples. Results Forty cats and kittens with confirmed panleukopenia were initially enrolled. Sixteen kittens were sampled until day 14, and 12 were followed to day 21. Median DNA viral copy numbers fell below the diagnostic cut-off by day 7, with 13/16, 6/16, 1/16 and 0/12 testing PCR-positive on days 3, 7, 14 and 21, respectively. The SNAP test was positive in 12/16 kittens on day 0 and only 3/16 on day 3. SNAP test results, diarrhea and systemic signs were inconsistent in relation to qPCR positivity post-diagnosis. Additional enteric pathogens were common. The presence of additional pathogen types was suggestive of a longer PCR shedding duration, but this was not tested statistically owing to the small sample size. Conclusions and relevance These findings suggest that cats should be isolated for at least 14 days after a diagnosis of FP, but that release from isolation after this point is reasonable, in association with a multifaceted infection control strategy. The study findings did not support using SNAP test results, diarrhea or systemic signs as proxy measures for virus shedding.

The objective of this study was to compare the fecal microbiota of two healthy teaching horse herds with that of client-owned horses from the same geographic areas. The fecal microbiota of client-owned horses from Ontario Canada (n = 15) and Florida, USA (n = 11) was compared with that teaching horses from the University of Guelph, Ontario, Canada (n = 10) and the University of Florida, Florida, USA (n = 15). The fecal microbiota was characterized by sequencing of bacterial DNA using the V4 hypervariable region of the 16S rRNA gene. The diversity (inverse Simpson index) of the fecal microbiota was significantly higher in teaching than client owned horses from the same geographical area (P.05). The community membership (Jaccard Index) and structure (Yue and Clayton index) of teaching horses was also significantly different from that of client owned horses from the same geographical area (AMOVA P.001). The bacterial membership and structure of the fecal microbiota of Ontario and Florida teaching horses were significantly different, while the bacterial membership, but not the structure of Ontario and Florida client owned horses was significantly different (AMOVA P.001). In all four groups of healthy horses, Lachnospiraceae, Ruminococcaceae, Bacteroidales, Clostridiales, and Treponema were detected in high relative abundance. The fecal microbiota of healthy horses from teaching herds kept in the same environment with identical management practices differs significantly from that of horses housed in different facilities with dissimilar management practices. Our results suggest an effect of the environment and management practices on the gastrointestinal microbiota. Researchers should attempt to include healthy horses from the same farm with similar management as control groups when comparing with diseased horses.

The blacklegged tick ( Ixodes scapularis), which transmits Borrelia burgdorferi, the causative agent of Lyme disease, has undergone rapid range expansion in Ontario. In horses, Lyme disease remains an enigmatic disease, with limited understanding of the pathogenesis and many issues pertaining to selection and interpretation of laboratory tests. We evaluated B. burgdorferi seropositivity in naturally exposed horses over a 12-mo period and compared paired samples with 2 common serologic tests. Serum samples were collected in 2017, ~1 y after initial testing, from a cohort of 22 horses that were seropositive in a 2016 seroprevalence study. Samples were tested using a C6 ELISA and a multiplex ELISA targeting outer surface proteins A, C, and F. 1 y after initial testing, 14 of 22 (64%) horses remained seropositive; 7 (32%) were positive on the multiplex ELISA, 2 (9%) on C6 ELISA, and 5 (23%) on both tests. Repeatability was 100% for the C6 ELISA, and 95% for the multiplex ELISA, with no significant difference between paired sample multiplex titer values. Our results indicate strong intra-test reliability, although further investigation is required to determine the clinical significance of serologic testing.

Objectives The aim of this study was to optimize the diagnosis of feline panleukopenia virus (FPV) infection in a shelter setting by: (1) comparing the results of the canine parvovirus IDEXX SNAP Parvo (SNAP) point-of-care ELISA with a commercial FPV quantitative real-time PCR (qPCR) test; (2) assessing whether vomit and anal/rectal swabs could be used for early diagnosis; and (3) clarifying the interpretation of weak-positive SNAP test results. Methods The study included shelter cats and kittens with incomplete or unknown vaccination history that had clinical signs suspicious for feline panleukopenia and fecal SNAP and PCR tests performed within 24 h of onset. Feces, anal/rectal swabs and vomit were tested using SNAP and PCR, with fecal PCR utilized as the reference standard. Results One hundred and forty-five cats were included. Seventeen were diagnosed with FPV infection and 62 were negative; 66 could not be individually designated because they were co-housed. Sensitivity was as follows: fecal SNAP 55% (n = 102; 95% confidence interval [CI] 32–77); swab SNAP 30% (n = 55; 95% CI 7–65); swab PCR 77% (n = 55; 95% CI 46–95); and vomit PCR 100% (n = 17; 95% CI 16–100). Specificity was high (96–100%) for all sample and test types. For PCR-positive fecal samples, true-positive SNAP tests (including weak positives) had significantly higher DNA viral copy numbers than false-negative SNAP tests ( P = 0.0031). Conclusions and relevance The SNAP ELISA should be viewed as an initial diagnostic test to rule in feline panleukopenia. Positive fecal SNAP test results, including weak positives, are highly likely to be true positives in clinically affected animals. Negative results in clinically affected animals are unreliable and should be followed up with PCR testing.

Background Leptospirosis is a zoonotic disease of concern and an investigation of recent spatio-temporal trends of leptospirosis in dogs in the United States is needed. Leptospira PCR testing has become increasingly used in veterinary clinical medicine and these data might provide information on recent trends of disease occurrence. Objectives To identify and describe clusters of PCR-positive Leptospira test results in dogs in the United States. Animals Leptospira real-time PCR test results from dogs (n = 40 118) in the United States from IDEXX Laboratories, Inc., between 2009 and 2016 were included in the analysis. Methods In this retrospective study, spatio-temporal clusters for a real-time PCR-positive test were identified using the space-time permutation scan statistic and the centroid of the zip code reported for each test. A maximum spatial window of 20% of the population at risk, and a maximum temporal window of 6 months were used. Results Seven statistically significant space-time clusters of Leptospira real-time PCR-positive test results were identified across the United States: 1 each located within the states of Arizona (2016), California (2014-2015), Florida (2010), South Carolina (2015), and 1 each located within the south-central region (2015), midwest region (2014), and northeast region (2011). Clusters ranged from 3 to 108 dogs and were identified during all years under study, except 2009, 2012, and 2013. Conclusions and clinical importance The spatial and temporal components of leptospirosis in dogs in this study are similar to those in previous work. However, clusters were identified in new areas, demonstrating the complex epidemiology of this disease.

OBJECTIVE: To determine the use and barriers to uptake of a surgical safety checklist (SSC) after implementation in a veterinary teaching hospital. STUDY DESIGN: Voluntary online survey and retrospective study. SAMPLE POPULATION: All personnel actively involved in the Ontario Veterinary College Health Sciences Centre small animal surgery service between October 2, 2018 and June 28, 2019. METHODS: Surgical case logs and electronically initiated SSC were reviewed to calculate checklist use. The sample population was surveyed to identify factors and barriers associated with use of the SSC. Participants were allowed 1 month to respond, and five reminder emails were sent. RESULTS: Forth‐one of 50 (82%) participants completed the survey. The SSC was used in 374 of 784 (47.7%) surgeries. Use rates declined over sequential three‐month intervals (P

Prior to 2012, Echinococcus multilocularis was not known to occur in any host in Ontario, Canada. However, since that year, five cases of alveolar echinococcosis have been diagnosed in dogs that resided at the western end of Lake Ontario. In addition, E. multilocularis has been shown to be a common infection in wild canids (i.e. coyotes and foxes) across southern Ontario with a high-risk infection cluster in the area surrounding the western shores of Lake Ontario and northern shores of Lake Erie. In regions endemic for E. multilocularis, dog ownership is considered a risk factor for human alveolar echinococcosis. A study was therefore carried out to determine the prevalence of E. multilocularis intestinal infections in dogs within the high-risk infection cluster. From May to November 2018, faecal samples were collected from 477 dogs aged ≥6 months that visited 12 off-leash dog parks in the Halton, Hamilton and Niagara public health units. Faecal samples were analysed via a magnetic capture probe DNA extraction and real-time PCR method for E. multilocularis DNA. Overall, 0% (97.5% CI: 0%-0.80%) of samples tested positive. This result informs preventive recommendations for E. multilocularis infections in dogs in this region.

We tested swab specimens from pets in households in Ontario, Canada, with human COVID-19 cases by quantitative PCR for SARS-CoV-2 and surveyed pet owners for risk factors associated with infection and seropositivity. We tested serum samples for spike protein IgG and IgM in household pets and also in animals from shelters and low-cost neuter clinics. Among household pets, 2% (1/49) of swab specimens from dogs and 7.7% (5/65) from cats were PCR positive, but 41% of dog serum samples and 52% of cat serum samples were positive for SARS-CoV-2 IgG or IgM. The likelihood of SARS-CoV-2 seropositivity in pet samples was higher for cats but not dogs that slept on owners' beds and for dogs and cats that contracted a new illness. Seropositivity in neuter-clinic samples was 16% (35/221); in shelter samples, 9.3% (7/75). Our findings indicate a high likelihood for pets in households of humans with COVID-19 to seroconvert and become ill.

Current guidelines for the use of systemic antimicrobials for the treatment of superficial bacterial folliculitis in dogs include the recommendation that the disease be treated for a minimum of 3 weeks and for at least 1 week beyond clinical resolution. With increasing antimicrobial resistance being noted for bacteria involved in this condition, as well as the increased use of evidence-based medicine, this dogma needs to be reevaluated.

Objectives The primary aims of this study were to determine preferences of North American cat owners when they are prescribed an antimicrobial for their cat with regard to cost, method of administration and the importance of antibiotics for treating infections in people, and to establish baseline knowledge, attitudes and influencers of cat owners on antimicrobial resistance and stewardship. Methods An online questionnaire was used for data collection from two cat-owner groups: US cat owners and Canadian cat owners. Participants were queried on antimicrobial resistance and stewardship, and their preferences for their own cat when prescribed an antimicrobial, with respect to cost, method of drug administration and the importance of a drug for treating infections in people. Responses were evaluated through conjoint analysis and Likert-type questions. Data were analyzed using descriptive and analytic statistics. Results A total of 630 complete responses were included in the final analysis. Cost (37%) and method of administration (38%) were of similar participant preference when assessed using conjoint analysis. The importance of a drug for treating infections in people was lower priority (21%). The majority of cat owners preferred an antimicrobial that was ‘very important’ in treating human infections. A low proportion (21%) of participants responded that antimicrobial use in pets posed a risk to humans. Participants with a university education were more likely to respond that antimicrobial use in pets was a concern for people (31%; P Conclusions and relevance Cat owners prioritize antimicrobial cost and method of administration equally. Few cat owners recognized the human antimicrobial resistance risks associated with antimicrobial use in pets.

The association of microbiota with clinical outcomes and the taxa associated with colitis in horses remains generally unknown.Describe the fecal microbiota of horses with colitis and investigate the association of the fecal microbiota with the development of laminitis and survival.Thirty-six healthy and 55 colitis horses subdivided into laminitis (n = 15) and non-laminitis (n = 39, 1 horse with chronic laminitis was removed from this comparison) and survivors (n = 27) and nonsurvivors (n = 28).Unmatched case-control study. The Illumina MiSeq platform targeting the V4 region of the 16S ribosomal RNA gene was used to assess the microbiota.The community membership (Jaccard index) and structure (Yue and Clayton index) were different (analysis of molecular variance [AMOVA]; P .001) between healthy and colitis horses. The linear discriminant analysis effect size (LEfSe; linear discriminant analysis [LDA]3; P .05) and random forest analyses found Enterobacteriaceae, Lactobacillus, Streptococcus, and Enterococcus enriched in colitis horses, whereas Treponema, Faecalibacterium, Ruminococcaceae, and Lachnospiraceae were enriched in healthy horses. The community membership and structure of colitis horses with or without laminitis was (AMOVA; P .05). Enterobacteriaceae, Streptococcus, and Lactobacillus were enriched in horses with laminitis (LDA 3; P .05). The community membership (AMOVA; P = .008) of surviving and nonsurviving horses was different. Nonsurviving horses had an enrichment of Enterobacteriaceae, Pseudomonas, Streptococcus, and Enterococcus (LDA3; P .05).Differences in the microbiota of horses with colitis that survive or do not survive are minor and, similarly, the microbiota differences in horses with colitis that do or do not develop laminitis are minor.

Over the past decade, there has been an apparent increased frequency and widened distribution of canine leptospirosis in Canada, however, this has been minimally investigated. Availability and clinical uptake of Leptospira polymerase chain reaction (PCR)-based testing of dogs in Canada may provide important insight into the epidemiology of this canine and zoonotic infectious disease. Study objectives were to evaluate clinical canine Leptospira PCR test results from a large commercial laboratory to determine temporal and spatial distribution in Canada and identify dog, geographic and temporal risk factors for test-positive dogs. This cross-sectional study analyzed data obtained from IDEXX Laboratories, Inc. on 10,437 canine Leptospira PCR tests (blood and/or urine) submitted by Canada-based veterinarians (July 2009 to May 2018). Multivariable logistic regression was used to identify risk factors for test-positive dogs. Test-positive proportion varied widely annually (4.8–14.0%) and by location. Provinces with the highest test-positive proportion over the study period were Nova Scotia (18.5%) and Ontario (9.6%), with the prairie provinces (Manitoba and Alberta combined) having the lowest proportion (1.0%); the northern territories could not be evaluated due to limited testing. In the final model, dog age, sex, breed, month, and year test performed, and location (urban/rural, province) of the practice submitting the sample were significant predictors of a positive Leptospira PCR test. Dogs less than one year of age (OR = 2.1; 95% CI: 1.6–2.9), male sex (OR = 1.3; 1.1–1.5), toy breed (OR = 3.3; 2.5–4.4), and samples submitted from an urban practice (OR = 1.3; 1.0–1.8) had the greatest odds of a positive Leptospira PCR test as compared to referent groups. Significant two-way interactions between province-month and year-month highlight the complex spatial and temporal influences on leptospirosis occurrence in this region. Our work suggests a high incidence of canine leptospirosis regionally within Canada. Identifiable dog and location factors may assist in future targeted prevention efforts.

Using next-generation sequencing DNA barcoding, we aimed to determine: 1) if the larval bloodmeal can be detected in Ixodes scapularis nymphs and 2) the post-moult temporal window for detection of the larval bloodmeal. Subsets of 30 nymphs fed on a domestic rabbit (Oryctolagus cuniculus Linnaeus, Lagomorphia: Leporidae) as larvae were reared and frozen at 11 time points post-moult, up to 150 d. Vertebrate DNA was amplified using novel universal (UP) and species-specific primers (SSP) and sequenced for comparison against cytochrome c oxidase subunit I barcodes to infer host identification. Detectable bloodmeals decreased as time since moult increased for both assays. For the SSP assay, detection of bloodmeals decreased from 96.7% (n = 29/30) in day 0 nymphs to 3.3% (n = 1/30) and 6.7% (n = 2/30) at 4- and 5-mo post-moult, respectively. A shorter temporal detection period was achieved with the UP assay, declining from 16.7% (n = 5/30) in day 0 nymphs to 0/30 in 3-d-old nymphs. Bloodmeal detection was nonexistent for the remaining cohorts, with the exception of 1/30 nymphs at 2-mo post-moult. Host detection was significantly more likely using the SSP assay compared to the UP assay in the first three time cohorts (day 0: χ 2 = 39.1, P < 0.005; day 2: χ 2 = 19.2, P < 0.005; day 3: χ 2 = 23.3, P < 0.005). Regardless of the primer set used, the next-generation sequencing DNA barcoding assay was able to detect host DNA from a larval bloodmeal in the nymphal life stage; however, a short window with a high proportion of detection post-moult was achieved.

Objective To identify factors associated with surgical site infection (SSI) after tibial plateau leveling osteotomy (TPLO). Study design Retrospective case series. Animals Dogs (n = 541) that underwent TPLO (n = 659). Methods Medical records of dogs that underwent TPLO from 2011-2018 were reviewed. Data collected included perioperative and postoperative antimicrobial administration, stifle inspection, duration of surgery and anesthesia, comorbidities, and development of SSI including timing, microbiological investigation, and implant removal. Referring veterinarians were contacted for all dogs without a recorded return visit. Risk factors for SSI were assessed by using a multivariable logistic regression model built by using a stepwise approach. Results Surgical site infection was documented in 71 of 659 (11%) TPLO, with methicillin-resistant Staphylococcus pseudintermedius accounting for 20 of 71 (28%) infections. Protective factors against SSI included administration of postoperative antimicrobials (odds ratio [OR] 0.263; 95% CI = 0.157, 0.442) and timing of preoperative antimicrobial administration. Preoperative antimicrobial timing was protective against SSI when it was administered more than 60 minutes before the first incision compared with administration within 30 minutes (OR 0.275; 95% CI = 0.112, 0.676) or within 60 minutes (OR 0.419; 95% CI = 0.189, 0.929) of the first incision. Conclusion Early administration of perioperative antimicrobials and postoperative antimicrobial administration were protective against SSI after TPLO. Clinical significance Antimicrobials can influence the risk of SSI after TPLO. Perioperative and postoperative antimicrobial administration timing should be considered to reduce SSI.

OBJECTIVE To characterize the in vitro elution of amikacin and Dispersin B (β-N-acetylglucosaminidase) in a degradable hydrogel. STUDY DESIGN In vitro, prospective study. METHODS Amikacin (group A; 40 mg/mL), Dispersin B (group D; 70 μg/mL), or combined amikacin and Dispersin B (group AD; 40 mg/mL and 70 μg/mL, respectively) were added to a hydrogel. Ten aliquots per group were incubated in phosphate-buffered saline that was exchanged at 1, 4, 8, 12, and 24 hours and then once daily for 10 days. Eluted amikacin and Dispersin B were quantitated by using an amikacin reagent kit and a Dispersin B enzyme-linked immunosorbent assay kit, respectively. Time point drug concentrations were compared between groups by using repeated-measures analysis of variance, and total drug elution was compared by using an area under the curve calculation. RESULTS Amikacin alone, Dispersin B alone, and amikacin and Dispersin B combined together underwent rapid elution in the first 24 hours, followed by a gradual decrease over 10 days. The concentration of Dispersin B eluted in group D was higher at 1 day and lower from day 5 to day 10 compared with that in group AD. The concentration of amikacin eluted in group A was higher at 1, 4, and 8 hours and on day 10 and lower on day 1 compared with that in group AD. The total elution of amikacin was greater from group AD compared with that from group A (P = .02). CONCLUSION Combining amikacin and Dispersin B had an affect on the total elution of amikacin but not Dispersin B. CLINICAL SIGNIFICANCE The combination of amikacin and Dispersin B in a degradable hydrogel could allow local treatment of complex infections without the requirement for multiple invasive procedures.

The first Canadian H3N2 canine influenza A outbreak involving an Asian-origin H3N2 canine influenza virus (CIV) began in southwestern Ontario, Canada, in late December 2017. More H3N2 CIV cases were identified in central and eastern Ontario between March and October 2018. Based on epidemiological investigation, 5 clusters were identified (C1, C2, C3a, C3b, and C4); however, the origin of infection has only been revealed for epidemiological cluster C1. Here, we use phylogenetic analyses to unravel the links of virus transmission between the 5 epidemiological clusters and the origin of infection for all epidemiological clusters. Our results demonstrate that the Canadian H3N2 CIV sequences were grouped into four distinct phylogenetic clusters with minimal genetic diversity between these clusters. Large scale phylogenetic analysis of H3N2 CIV from around the globe showed that the Canadian CIVs formed a distinct new clade along with CIVs that have been circulating in the USA since 2017–2018 and in China since 2017. This clade shares a common ancestor of Asian origin. This study concludes that the H3N2 CIV outbreak in Ontario was driven by multiple introductions of South Korean/Chinese-origin H3N2 CIVs over 10 months.

OBJECTIVE To describe perioperative antimicrobial use in horses undergoing elective arthroscopy. STUDY DESIGN Retrospective study. SAMPLE POPULATION Horses that underwent elective arthroscopy at one institution between July 2016 and May 2018, excluding those with a suspected infectious orthopedic disease or with a comorbidity that may have impacted prophylactic antimicrobial use decisions. METHODS Medical records were reviewed to evaluate preoperative, intraoperative, and postoperative antimicrobial drug selection, dose, and timing. Associations between body weight and underdosing were evaluated by using analysis of variance, χ2 test was used for categorical comparisons, and least squares fit was used to evaluate factors associated with duration of postoperative antimicrobials. RESULTS Among 150 horses, 149 (99.3%) received systemic preoperative antimicrobials. Only 53 (40.2%) horses were administered doses within 60 minutes of surgical incision. First incision was performed more than two half-lives after administration of sodium penicillin in 46 of 131 (35.1%) horses but in only 1 of 106 (0.8%) horses that received trimethoprim-sulfadoxine. Body weight was associated with underdosing for penicillin (P = .0075) and trimethoprim-sulfadoxine (P = .002) but not gentamicin (P = .92). Twenty-six (17%) horses received one postoperative antimicrobial dose, while antimicrobials were continued in hospital for a mean of 22.3 ± 4.4 hours after surgery in the other 123 horses. Among the 149 discharged horses, 115 (77.2%) were prescribed antimicrobials after discharge (range, 3-10 days; median, 3 days, interquartile range, 0 days). CONCLUSION Deviations from common recommendations were apparent and provide evidence for the requirement to develop interventions to optimize perioperative prophylaxis. CLINICAL SIGNIFICANCE Perioperative antimicrobial use practices should be regularly assessed to provide a benchmark and identify areas for intervention.

Objective To evaluate the presence of quaternary ammonium compound (QAC) (resistance genes, qac A/B, smr, qacG, and qacJ, in clinical isolates of methicillin-susceptible Staphylococcus pseudintermedius (MSSP) and methicillin-resistant S pseudintermedius (MRSP) from dogs and the impact on in vitro chlorhexidine susceptibility. Study design Experimental in vitro study. Sample population Seventy isolates from dogs colonized or infected with MRSP (n = 50) or MSSP (n = 20). Methods Agar dilution was used to determine the minimum inhibitory concentration (MIC) of chlorhexidine digluconate. Real-time polymerase chain reaction was used to detect the presence of QAC resistance genes, qacA/B, smr, qacG, and qacJ genes. Results One or more qac genes were identified in 52 of 70 (74%) isolates. Overall, there was no association between chlorhexidine MIC and the presence of one or more qac genes (P = .85) or the presence of qacA/B (P = .31), smr (P = .72) or qacJ (P = .93) individually. There was an association between qacG and MIC (P = .012), with a median MIC of 1.5 μg/mL for isolates possessing this gene and 1 μg/mL for those not possessing it. Conclusion Quaternary ammonium compound resistance genes were present in MRSP and MSSP isolates. With the exception of qacG, the presence of these genes was not associated with increased MIC. All isolates exhibited MIC 5000 to 80 000 times lower than the concentration recommended for use. Clinical significance Despite the presence of QAC genes, chlorhexidine digluconate should be effective against MRSP and MSSP if used correctly.

High prevalences of Cryptosporidium and Giardia were recently found in enteric illness patients in the Qikiqtaaluk region of Nunavut, Canada, with a foodborne, waterborne or animal source of parasites suspected. Clams (Mya truncata) are a commonly consumed, culturally important and nutritious country food in Iqaluit; however, shellfish may concentrate protozoan pathogens from contaminated waters. The goal of this work was to investigate clams as a potential source of Cryptosporidium and Giardia infections in residents in Iqaluit, Nunavut. The objectives were to estimate the prevalence and genetically characterize Cryptosporidium and Giardia in locally harvested clams. Clams (n = 404) were collected from Iqaluit harvesters in September 2016. Haemolymph (n = 328) and digestive gland (n = 390) samples were screened for Cryptosporidium and Giardia via PCR, and amplified products were further processed for sequence analyses for definitive confirmation. Giardia DNA was found in haemolymph from 2 clams, while Cryptosporidium was not detected. The two Giardia sequences were identified as zoonotic Giardia enterica assemblage B. The overall prevalence of Giardia in clams near Iqaluit was low (0.6%) compared with other studies in southern Canada and elsewhere. The presence of Giardia DNA in clams suggests human or animal faecal contamination of coastal habitat around Iqaluit in shellfish harvesting waters. Results from this study are intended to inform public health practice and planning in Inuit Nunangat.

Antimicrobial resistance is a complex One Health issue that exists in both human and veterinary medicine. To mitigate this ever-growing problem, efforts have been made to develop guidelines for appropriate antimicrobial use (AMU) across sectors. In veterinary medicine, there are notable literature gaps for proper AMU in minor species. We conducted a structured narrative review covering the years of July 2006 – July 2021 to find antimicrobial treatments for common bacterial infections in exotic (birds, rodents, reptiles, and others), small flock (chickens, turkeys, and other fowl), and backyard small ruminant (sheep and goats) species. We retrieved a total of 4728 articles, of which 21 articles met the criteria for our review. Studies were grouped according to species, syndrome, and body system affected. Other data extracted included the bacterial pathogen(s), treatment (active ingredient), and geographical origin. Body systems reported included: intra-oral (n = 4), gastrointestinal (n = 1), respiratory (n = 2), reproductive (n = 1), skin (n = 3), aural (n = 1), ocular (n = 4), and other/multisystem (n = 5). By species, our search resulted in: rabbit (n = 5), rat (n = 2), guinea pig (n = 1), chinchilla (n = 1), guinea pig and chinchilla (n = 1), avian species (n = 1), psittacine birds (n = 2), loris and lorikeets (n = 1), turtles (n = 2), lizards (n = 1), goats (n = 2) and sheep (n = 2). The results of our findings identified a distinct gap in consistent antimicrobial treatment information for commonly encountered bacterial conditions within these species. There is a persisting need for clinical trials that focus on antibacterial treatment to strengthen the evidence base for AMU within exotic, small flock, and backyard small ruminant species.

A 4-y-old, female mixed-breed dog was presented to the Ontario Veterinary College for further evaluation of multiple pulmonary and hepatic masses, intrathoracic lymphadenitis, and recent development of a pyogranulomatous pleural effusion. Along with other comprehensive tests, a thoracic lymph node biopsy was performed, and

Advances in gene sequence technology and data analysis have enabled the detection and taxonomic identification of microorganisms in vivo based on their unique RNA or DNA sequences. Standard culture techniques can only detect those organisms that readily grow on artificial media in vitro. Culture-independent technology has been used to provide a more accurate assessment of the richness (total number of species) and diversity (relative abundance of each species) of microorganisms present in a prescribed location. The microbiome has been defined as the genes and genomes of all microbial inhabitants within a defined environment. Microorganisms within a microbiome interact with each other as well as with the host. A microbiome is dynamic and may change over time as conditions within the defined environment become altered. In oral health, neither gingivitis nor periodontitis is present, and the host and microbiome coexist symbiotically without evoking an inflammatory response. The circumstances that cause a shift from immune tolerance to a proinflammatory response remain unknown, and a unified, all-encompassing hypothesis to explain how and why periodontal disease develops has yet to be described. The purpose of this review is to clarify the current understanding of the role played by the oral microbiome in dogs and cats, describe how the microbiome changes in periodontal disease, and offer guidance on the utility of systemic antimicrobial agents in the treatment of periodontitis in companion animals.

The purpose of this study was to characterize the fecal microbiota of horses with acute and chronic diarrhea before and after fecal microbiota transplantation (FMT). Six client-owned horses with acute and chronic diarrhea received FMT from 2 healthy donor horses. Microbiota analysis using next-generation sequencing was performed on fecal samples collected before and 2 and 7 d after FMT. Signs of diarrhea improved in 4 horses, whereas the remaining 2 horses did not survive. There was a significant difference in the number of bacterial species between donors and recipients (P < 0.05). The Order Lactobacillales and the genera Lactobacillus, Intestinimonas, and Streptococcus were increased in the microbiota of diarrheic horses, and Saccharofermentans genus increased in healthy donors. The results suggest that FMT from the healthy donors was not effective over a 7-day period as it did not change the fecal microbiota of the diarrheic horses. Further research to improve the efficacy of FMT in horses is needed.

Here, we assessed the efficacy of a short-course multimodal therapy (enrofloxacin, azithromycin, fenbendazole, and paromomycin) to eliminate common macaque endemic pathogens (EPs) and evaluated its impact on gastrointestinal (GI) microbiota, mucosal integrity, and local and systemic inflammation in sixteen clinically healthy macaques. Treatment combined with expanded practices resulted in successful maintenance of rhesus macaques (RM) free of common EPs, with no evidence of overt microbiota diversity loss or dysbiosis and instead resulted in a more defined luminal microbiota across study subjects. Creation of a GI pathogen free (GPF) status resulted in improved colonic mucosal barrier function (histologically, reduced colonic MPO+, and reduced pan-bacterial 16s rRNA in the MLN), reduced local and systemic innate and adaptive inflammation with reduction of colonic Mx1 and pSTAT1, decreased intermediate (CD14+CD16+) and non-classical monocytes (CD14-CD16+), reduced populations of peripheral dendritic cells, Ki-67+ and CD38+ CD4+ T cells, Ki-67+IgG+, and Ki-67+IgD+ B cells indicating lower levels of background inflammation in the distal descending colon, draining mesenteric lymph nodes, and systemically in peripheral blood, spleen, and axillary lymph nodes. A more controlled rate of viral acquisition resulted when untreated and treated macaques were challenged by low dose intrarectal SIVmac239x, with an ~100 fold increase in dose required to infect 50% (AID50) of the animals receiving treatment compared to untreated controls. Reduction in and increased consistency of number of transmitted founder variants resulting from challenge seen in the proof of concept study directly correlated with post-treatment GPF animal’s improved barrier function and reduction of key target cell populations (Ki-67+ CD4+T cells) at the site of viral acquisition in the follow up study. These data demonstrate that a therapeutic and operational strategy can successfully eliminate varying background levels of EPs and their associated aberrant immunomodulatory effects within a captive macaque cohort, leading to a more consistent, better defined and reproducible research model., Author summary Simian Immunodeficiency virus in macaques remains the most translational model for HIV. Macaques are also key models for other infectious diseases and colitis, where background colon health and inflammation could confound experimental results. To address these issues SPF breeding colonies were established to exclude specific viruses detrimental to mucosal and systemic health. To further improve macaque models, we established a gastrointestinal pathogen free (GPF) colony by administration of a multimodal therapeutic regimen for common endemic pathogens (EPs) and established expanded operational practices for continued exclusion. Through extensive longitudinal microbiota, parasitology, microbiology, and tissue sampling we demonstrated that our treatment and exclusion practices successfully eliminated common EPs, improved mucosal barriers, and reduced mucosal and systemic inflammation resulting in less inter-animal variation without overt evidence of microbiota disruption. Finally, compared to treatment-naïve controls, GPF animals challenged with SIV intrarectally demonstrated a more controlled and consistent rate of SIV acquisition, further indicating underlying EPs even at subclinical levels may cause deleterious variations between study subjects. Collectively the GPF macaque represents a model that eliminates a significant source of morbidity, reduces inter-animal variability, and thus has the potential to improve both animal welfare and research outcomes.

Background There are limited studies investigating the use of fecal microbial transplant (FMT) in dogs with inflammatory bowel disease (IBD). The aim of this preliminary study was to assess the feasibility of adding FMT to standard therapy (corticosteroids and a hypoallergenic diet) for dogs with IBD and to and to describe the changes in measured outcomes after 30 days of treatment. Methods Thirteen client-owned dogs with IBD were enrolled in this double blinded, randomized clinical trial. All dogs received corticosteroid therapy and a hypoallergenic diet; dogs were randomized to receive either placebo or FMT. Measured outcomes included the canine chronic enteropathy clinical activity index (CCECAI) at 1 week and 1 month after enrolment. Fecal microbiota were analyzed after extracting DNA from fecal samples and profiling using 16S amplicon sequencing. Dogs in the placebo group not responding to treatment after 1 month were offered FMT. Results The CCECAI significantly decreased over time in both groups (p = 0.001). There were no significant differences between the CCECAI of the placebo and FMT group at each time point (F test from ANOVA, p = 0.40). No adverse effects were reported in the 30 days following FMT. Conclusions The addition of FMT to standard therapy for IBD was feasible. No significant differences were observed in the CCECAI between groups at each time point. Large scale clinical trials can be performed using these methods to evaluate the longer term effect of FMT on clinical signs, microbial diversity, and other outcomes.

Canine influenza virus (CIV) A(H3N2) was identified in 104 dogs in Ontario, Canada, during December 28, 2017-October 30, 2018, in distinct epidemiologic clusters. High morbidity rates occurred within groups of dogs, and kennels and a veterinary clinic were identified as foci of infection. Death attributable to CIV infection occurred in 2 (2%) of 104 diagnosed cases. A combination of testing of suspected cases, contact tracing and testing, and 28-day isolation of infected dogs was used, and CIV transmission was contained in each outbreak. Dogs recently imported from Asia were implicated as the source of infection. CIV H3N2 spread rapidly within groups in this immunologically naive population; however, containment measures were apparently effective, demonstrating the potential value of prompt diagnosis and implementation of CIV control measures.

Source at https://doi.org/10.1002/cre2.240. Background - Dog‐assisted therapy in the dental clinic may be an attractive alternative to sedation for anxious patients. Including a dental therapy dog in a clinical setting introduces new hazards and potential risks to health and safety for both humans and animal. Objectives - The study aims to describe potential hazards associated with risks to humans by having a therapy dog present in the dental clinic and to provide guidance on best practices to minimise and control risks for the patients, the dentist, and the dental clinic staff. Materials and Methods - Literature searches in Medline, Clinicaltrials.gov, and Google Scholar for qualitative and quantitative assessments of hazards and risks associated with the use of therapy dogs in health care settings, in combination with a review of the reference list of the included studies. Identified hazards and risks were analysed with respect for the health and welfare of humans in a dental clinic setting that involves the presence of a therapy dog. Results - Potential risks to health and safety for humans in dental clinics that offer dog‐assisted therapy can be categorised within four general categories of hazards: the dog as a source of zoonotic pathogens and human diseases, exposure to canine allergens, adverse animal behaviour, and dangers associated with high activity in a congested dental clinic operatory. Risks to humans are reduced by maintaining awareness amongst the dental clinic staff and the dog handler of all potential hazards in the dental clinic, and on how to reduce these hazards as well as adverse events that may scare the dental therapy dog. Conclusions - Risks to the health and safety of humans in the presence of therapy dog in the clinics are present but are low if the dental clinical staff and dog handlers comply with best practices.

Bats are associated with the emergence of several mammalian diseases. Their sessional migration, and tendency to form large colonies in close proximity to human habitats enables effective intra- and inter-species transmission of pathogens. Clostridioides difficile is an important enteric pathogen in humans and animals; however, the source of its dissemination in the population is unknown. The purpose of this study was to determine the prevalence of C. difficile in bats, and to characterize C. difficile isolates. Feces (n = 93) was sampled from bats during their migration across Europe. Eighteen samples (19.4%) were positive for C. difficile; ribotypes 078, 056, and a new ribotype CDB3 were identified. Clostridioides difficile ribotypes 078 and 056 are associated with human and animal diseases. The C. difficile prevalence and ribotypes in this study do not necessarily identify bats as a significant source, but more likely as an indicator of C. difficile perpetuation in the environment.

There has been a marked increase in interest regarding complex microbial populations in recent years. The methodology used for microbial assessment has drastically changed over the last two decades and continues to advance at a rapid pace. Culture-based studies have been superseded by those based upon molecular methods, which have been largely used to discover new species and to better characterize complex communities, mainly driven by the advances in DNA sequencing, termed 'next generation sequencing'. These methodologies have allowed for a better understanding of the relationship between hosts and their microbiotas, which have important roles in health maintenance and in the pathophysiology of wide ranging conditions such as obesity, diabetes, allergic diseases and even behavioural changes. While most widely used in humans, these approaches are now commonly used in veterinary research, with increasing interest in direct clinical applications. As these methods provide novel insights that will constitute the basis for the development of new therapeutic and prevention strategies, and as commercial efforts to offer microbiota assessment as a clinical tool expand, it is essential for researchers and clinical veterinarians to understand and have the tools to be able to interpret research performed in this new fascinating field. The objective of this review is to describe some of the most common methods for characterization of microbial communities and to provide an overview of the basic concepts necessary for good interpretation of the research performed in this field.

Clostridium (Clostridioides) difficile has been identified in humans and a wide range of animal species, but there has been little study of remote animal populations with limited human contact. The objective of this study was to determine the prevalence and types of C. difficile in wild and captive polar bears (Ursus maritimus). Fecal samples were collected from two populations of wild polar bears in Nunavut Canada; M’Clintock Channel and Hudson Strait (Davis Strait or Foxe Basin), as well as from a facility (PBJ) in Churchill, Manitoba that temporarily houses nuisance polar bears and from captive bears in a zoological park. Enrichment culture was performed and isolates were characterized by ribotyping and toxinotyping. Clostridium difficile was isolated from 24/143 (16.8%) of samples; 18/120 (15%) wild bear samples, 4/7 (57%) from the PBJ and 2/16 (13%) samples from three zoo bears. The prevalence of C. difficile was significantly higher in bears that were housed at the PBJ vs wild bears (P = 0.0042), but there was no difference between wild bears from M’Clintock Channel (14/100, 14%) and those from Hudson Strait (4/20, 20%) (P = 0.50). Fourteen of the 24 (58%) isolates were toxigenic; 13/18 (72%) wild bear isolates, 0/4 PBJ isolate and 1/2 zoo isolates. Four toxigenic ribotypes were identified, with one that possessed tcdB and cdtA predominating. None of the toxigenic isolates were ribotypes that have been identified previously by the authors. There was no overlap in toxigenic ribotypes between the different populations. Clostridium difficile was not uncommonly identified in polar bears, with differences in type distribution amongst the different regions. The presence of strains that have not been identified in humans or domestic animals suggests that polar bears may be a natural reservoir of unique strains of this important bacterium.

Historically, extended-spectrum cephalosporin resistance in bacteria from animals in Canada has been attributed to the SHV and CMY β-lactamase families. This pattern is beginning to change with the emergence of the blaCTX-M gene family among Escherichia coli recovered from various animal species. Here we analyze and compare whole genome sequences of blaCTX-M-positive E. coli isolates (n = 173) from dogs, chicken, swine, horses and beef cattle in Canada. Ten blaCTX-M variants were identified with blaCTX-M-1,-14, -15, -27 and blaCTX-M-55 being identified in most animal species. These variants occurred across many sequence types, suggesting that mobile genetic elements mediate the spread of blaCTX-M. The variants blaCTX-M-14, -15, -27 and blaCTX-M-55 are associated with the global spread of blaCTX-M in human clinical isolates and their presence could be indicative of transfer between humans and animals. These variants were also the principal variants identified among sequence type 131 isolates, which were not associated with any other species than dogs. These isolates carried the same blaCTX-M variants as E. coli isolates found in humans. Close contact may promote the transmission of these isolates between humans and companion animals.

Objectives The aim of this study was to evaluate changes in the conjunctival microbiota of shelter-housed cats with time, upper respiratory disease (URD) and famciclovir administration. Methods Cats were assigned to treatment groups on shelter entry. Healthy cats or cats with URD received ~30 mg/kg or ~90 mg/kg of famciclovir or placebo PO q12h for 7 days, or were untreated. Swabs were collected from ventral conjunctival fornices prior to (day 1) and immediately after (day 8) the treatment period. Microbiota analysis was conducted on 124 randomly selected swabs from healthy (56 swabs) or URD-affected (68 swabs) cats. Following DNA extraction and amplification of the V4 region of the 16S rRNA gene, sequences were assembled into operational taxonomic units (OTUs). Over-represented OTUs (as determined by linear discriminate analysis effect size), alpha and beta diversity, and median relative abundance of known feline ocular surface pathogens were assessed for the entire population and in 10 clinically relevant subpopulations of cats. Results Bacteria from 33 phyla and 70 genera were identified. Considering all cats, median relative abundance of Mycoplasma increased from day 1 to day 8, while Proteobacteria decreased. Community membership and structure (beta diversity) differed between days 1 and 8 for all famciclovir-treated cats (regardless of health status or dose) and healthy or URD-affected cats (regardless of famciclovir dose). Differences in taxonomic diversity within a sample (alpha diversity) between day 1 and day 8 were not detected in any subpopulations. Conclusions and relevance Within 1 week of shelter entry, there were significant changes in community structure and membership of the feline conjunctival microbiota, with a shift towards over-representation of feline ocular surface pathogens. Although famciclovir may impact beta diversity of the feline conjunctival microbiota, absence of change in alpha diversity suggests minimal shift in individual cats.

Methicillin-resistant Staphylococcus pseudintermedius skin infections are an increasing concern in veterinary medicine, especially when found in juvenile dogs with no prior antimicrobial exposure. The objectives of this study were to assess the prevalence of methicillin-resistant staphylococci in breeding bitches and survey antimicrobial administration by their breeders. A total of 17 breeders and 54 bitches were included. Bitches were housed in diverse environments throughout the Phoenix, Arizona, USA metropolitan region. Nasal and oral gingival swabs were submitted for selective culture. Methicillin-resistant Staphylococcus aureus was not present, while methicillin-resistant Staphylococcus pseudintermedius was found in only 1/54 (1.9%) dogs. Survey results revealed that 16 bitches, which did not include the 1 MRSP-positive dog, had received antimicrobials within 6 months prior to sampling. Regardless of the low point prevalence identified, veterinarians and breeders should be cognizant of risks for bacterial resistance with the overuse of antimicrobials.

We evaluated the prevalence of Brucella canis seropositivity in a convenience sample of dogs from commercial breeding kennels in Ontario, Canada. Overall, 127/1,080 (11.8%) dogs from 23/63 (37%) kennels were seropositive. The prevalence of positive dogs within kennels with >1 positive dog ranged from 3.9% to 100% (median 33%).

Background Among the measures taken to preserve the clinical efficacy of highest priority critically important antimicrobials (HP-CIAs), the WHO has recommended avoiding their use in food-producing animals. Little is known regarding the indications for which different antimicrobial classes are used in animals, even in countries where data on antimicrobial use are available. Objectives To outline, in a narrative review, the diseases for which HP-CIAs are used in veterinary medicine, highlighting incongruences with international guidelines and disease conditions where effective alternatives to HP-CIAs are missing. Methods Scientific literature, national reports and expert opinion were used to describe the indications for the use of HP-CIAs in the main food-producing (pigs, cattle and poultry) and companion (horses, dogs and cats) animal species. Results The most common indications for use of HP-CIAs are enteric and respiratory infections in pigs, cattle and poultry, urogenital infections in dogs and cats and respiratory infections in horses. In some instances, no valid and convenient alternatives to colistin and macrolides are available against certain porcine enteric and bovine respiratory pathogens. Effective, legal and convenient alternatives to HP-CIAs are also lacking for managing common infections in cats, for which oral administration is difficult, Rhodococcus equi infections in horses, some enteric and respiratory infections in poultry and MDR infections in all companion animal species. Conclusions Future research and stewardship programmes should focus on the disease conditions identified by this review to reduce the use of HP-CIAs in the veterinary sector.

Background Research in humans and mice suggests that obesity influences the abundance and diversity of gastrointestinal (GI) microbiota, and that an “obese microbiome” influences energy metabolism and fat storage in the host. Microbiota membership and composition have been previously assessed in healthy cats. However, research investigating the effects of obesity and weight loss on the cat’s fecal microbiota is limited. Therefore, this study’s objective was to evaluate differences in fecal microbial abundance and biodiversity, as well as serum cobalamin and folate concentrations in obese cats, before and after weight loss, and compare to lean cats. Fourteen lean and 17 obese healthy client-owned cats were fed a veterinary therapeutic weight loss food at maintenance energy requirement for 4 weeks. At the end of week 4, lean cats finished the study, whereas obese cats continued with a 10-week weight loss period on the same food, fed at individually-tailored weight loss energy requirements. Body weight and body condition score were recorded every 2 weeks throughout the study. At the end of each period, a fecal sample and food-consumption records were obtained from the owners, and serum cobalamin and folate concentrations were analysed. DNA was extracted from fecal samples, polymerase chain reaction (PCR) was performed, and products were sequenced using next-generation sequencing (Illumina MiSeq). Results No significant differences in the relative abundance of taxa and in biodiversity indices were observed between cats in either group (P > 0.05 for all tests). Nevertheless, some significantly enriched taxa, mainly belonging to Firmicutes, were noted in linear discriminant analysis effect size test in obese cats before weight loss compared to lean cats. Serum cobalamin concentrations were significantly higher in lean compared to obese cats both before and after weight loss. Serum folate concentrations were higher in obese cats before weight loss compared to after. Conclusions The association between feline obesity and the fecal bacterial microbiota was demonstrated in enriched taxa in obese cats compared to lean cats, which may be related to enhanced efficiency of energy-harvesting. However, in obese cats, the fecal microbial abundance and biodiversity were only minimally affected during the early phase of a standardized weight loss plan.

The utilization of meropenem in a small animal veterinary teaching hospital over a 7-year period was retrospectively analyzed, and culture (CBD) versus empiric-based decisions (EBD) were compared. Meropenem was infrequently prescribed at a rate of 0.50 prescriptions/1000 admissions in cats and 0.58/1000 in dogs. The most common condition for meropenem prescription in both cats and dogs was septic peritonitis (15/52, 28.8%). Overall 65.4% of meropenem prescriptions were initiated without, or prior to, culture results indicating a need for the drug. Based on retrospective analysis of culture and susceptibility results, only 2.9% of empirical meropenem selections were indicated, while the majority were not indicated (52.9%), or of questionable indication (44.2%).

The goal of this study was to determine the frequency of resistance to extended-spectrum cephalosporins (ESCs) in Escherichia coli and other Enterobacterales from turkeys in Canada and characterize the associated resistance determinants. Pooled fecal samples were collected in 77 turkey farms across British Columbia, Québec, and Ontario. Isolates were obtained with and without selective enrichment cultures and compared to isolates from diagnostic submissions of suspected colibacillosis cases in Ontario. Isolates were identified using MALDI-TOF and susceptibility to ESCs was assessed by disk diffusion. The presence of blaCMY, blaCTX-M, blaTEM, and blaSHV was tested by PCR. Transformation experiments were used to characterize blaCMY plasmids. Genome sequencing with short and long reads was performed on a representative sample of blaCTX-M-positive isolates to assess isolates relatedness and characterize blaCTX-M plasmids. For the positive enrichment cultures (67% of total samples), 93% (587/610) were identified as E. coli, with only a few other Enterobacterales species identified. The frequency of ESC resistance was low in E. coli isolates from diagnostic submission (4%) and fecal samples without selective enrichment (5%). Of the ESC-resistant Enterobacterales isolates from selective enrichments, 71%, 18%, 14%, and 8% were positive for blaCMY, blaTEM, blaCTX-M, and blaSHV, respectively. IncI1 followed by IncK were the main incompatibility groups identified for blaCMY plasmids. The blaCTX-M-1 gene was found repeatedly on IncI1 plasmids of the pMLST type 3, while blaCTX-M-15, blaCTX-M-55, and blaCTX-M-65 were associated with a variety of IncF plasmids. Clonal spread of strains carrying blaCTX-M genes between turkey farms was observed, as well as the presence of an epidemic blaCTX-M-1 plasmid in unrelated E. coli strains. In conclusion, Enterobacterales resistant to ESCs were still widespread at low concentration in turkey feces two years after the cessation of ceftiofur use. Although blaCMY-2 is the main ESC resistance determinant in E. coli from Canadian turkeys, blaCTX-M genes also occur which are often carried by multidrug resistance plasmids. Both clonal spread and horizontal gene transfer are involved in parallel in the spread of blaCTX-M genes in Enterobacterales from Canadian turkeys.

BACKGROUND Fecal water syndrome (FWS) is long-standing and common in horses, particularly in central Europe. No large epidemiological data sets exist, and the cause remains elusive. Dysbiosis could play a role in pathogenesis. OBJECTIVES To evaluate whether dysbiosis is present in horses with FWS when compared to stable-matched control horses in spring and autumn. ANIMALS Fecal samples were collected from horses with FWS (n = 16; 9 mares, 7 geldings) and controls (n = 15; 8 mares, 7 geldings). METHODS The bacterial microbiome of samples collected in spring and autumn of 2016 was analyzed using high-throughput sequencing. Differences in relative abundance of bacterial taxa, alpha diversity, and beta diversity indices were assessed between horses with FWS and controls based on season. RESULTS Differences in microbial community composition based on time point and health status were not observed on any taxonomic level. Limited differences were seen on linear discriminant analysis effect size analysis. No difference in alpha diversity indices was observed including richness, diversity based on health status, or time point. No effect of health status on microbial community membership structure was observed. CONCLUSIONS AND CLINICAL IMPORTANCE Limited differences were found in the bacterial microbiota of horses with and without FWS, regardless of season. Further research is needed to elucidate the role of microbiota in the development of FWS.

BACKGROUND Recently, the blacklegged tick (Ixodes scapularis), which is the vector of Borrelia burgdorferi, has undergone a range expansion from the northeastern and mid-west United States to areas of southeastern Canada, including parts of Ontario. Understanding the seroprevalence of antibodies against B. burgdorferi in horses and risk factors for exposure is important for monitoring and preventing this emerging disease. STUDY DESIGN Cross-sectional study of 551 horses in southern, central, and eastern Ontario, Canada. OBJECTIVES To assess the seroprevalence of B. burgdorferi in horses in Ontario, Canada; to evaluate risk factors associated with seropositivity; and, to compare the performance of two diagnostic tests. METHODS Serum samples were obtained from clinically healthy horses in Ontario, Canada, along with completed questionnaires that were used for the risk factor analysis. Sera were tested with a Multiplex ELISA (Animal Health Diagnostic Center, Cornell University) and C6 ELISA (IDEXX SNAP® 4Dx® Plus test, IDEXX Laboratories). RESULTS The seroprevalence of B. burgdorferi on at least one test was 17% (91/551), though only 15 (16%) horses tested positive with both tests. A spatial cluster of cases was detected in Eastern Ontario. The odds of being seropositive for B. burgdorferi on the C6 ELISA were significantly increased when oak trees were present by pastures (OR = 7.3 (1.8-29.2), P = .005), while the odds were significantly decreased when regular tick checks were performed (OR = 0.1 (0.01-0.7), P = 0.02). MAIN LIMITATIONS Recruitment focused on known areas with blacklegged ticks as well as areas of higher horse density, which may have led to selection bias. CONCLUSIONS The expansion of blacklegged tick populations poses an ongoing risk for horses. Assessment of diagnostic testing options and risk factors is important for diagnosis and prevention, and with further investigation this information may be used to propose changes in management.

OBJECTIVE To determine the effects of silver-coated versus standard silicone urinary catheters on the incidence of catheter-associated bacteriuria (CAB) and catheter-associated urinary tract infection (CAUTI) in dogs. DESIGN Randomized controlled clinical trial. ANIMALS 36 dogs requiring urinary bladder catheterization for ≥ 24 hours. PROCEDURES Dogs were randomly assigned to receive a silver-coated or non–silver-coated (control) silicone Foley catheter. Urine samples for cytologic examination and bacterial culture were collected at the time of catheter insertion and daily until catheters were removed (≥ 24 hours to 7 days later). Results were compared between groups. RESULTS No significant differences were identified between catheter groups in the incidence of CAB or CAUTI. Although the median time to development of cytologically detected bacteriuria, culture-detected bacteriuria, and CAUTI did not differ significantly between groups, median time to CAB development (either method) was significantly longer for dogs that received a control catheter rather than a silver-coated catheter. For both types of catheters combined, older age was a significant predictor of culture-detected bacteriuria, and longer duration of catheterization was a significant predictor of culture-detected bacteriuria and overall CAB. CONCLUSIONS AND CLINICAL RELEVANCE Silver-coated urinary catheters provided no clinical benefit over standard urinary catheters for the dogs of this study and were associated with earlier development of CAB but not CAUTI. A larger prospective study is required to definitively determine whether the use of silver-coated urinary catheters should or should not be considered to reduce the risk of CAB or CAUTI in dogs.

Significance Skin forms a critical protective barrier between a mammal and its external environment. Baseline data on the mammalian skin microbiome elucidates which microorganisms are found on healthy skin and provides insight into mammalian evolutionary history. To our knowledge, this study represents the largest existing mammalian skin microbiome survey. Our findings demonstrate that human skin is distinct, not only from other Primates, but from all 10 mammalian orders sampled. Identifying significant similarities between branching of mammalian phylogenetic trees and relatedness trees for their corresponding microbial communities raises the possibility that mammals have experienced coevolution between skin microbiota and their corresponding host species., Skin is the largest organ of the body and represents the primary physical barrier between mammals and their external environment, yet the factors that govern skin microbial community composition among mammals are poorly understood. The objective of this research was to generate a skin microbiota baseline for members of the class Mammalia, testing the effects of host species, geographic location, body region, and biological sex. Skin from the back, torso, and inner thighs of 177 nonhuman mammals was sampled, representing individuals from 38 species and 10 mammalian orders. Animals were sampled from farms, zoos, households, and the wild. The DNA extracts from all skin swabs were amplified by PCR and sequenced, targeting the V3-V4 regions of bacterial and archaeal 16S rRNA genes. Previously published skin microbiome data from 20 human participants, sampled and sequenced using an identical protocol to the nonhuman mammals, were included to make this a comprehensive analysis. Human skin microbial communities were distinct and significantly less diverse than all other sampled mammalian orders. The factor most strongly associated with microbial community data for all samples was whether the host was a human. Within nonhuman samples, host taxonomic order was the most significant factor influencing skin microbiota, followed by the geographic location of the habitat. By comparing the congruence between host phylogeny and microbial community dendrograms, we observed that Artiodactyla (even-toed ungulates) and Perissodactyla (odd-toed ungulates) had significant congruence, providing evidence of phylosymbiosis between skin microbial communities and their hosts.

In southern Ontario, Canada, there is a lack of information concerning the prevalence of intestinal parasites in dogs. As such, this study aimed to characterize the prevalence of intestinal parasites in dogs visiting off-leash parks in the region using sucrose double centrifugation and Fecal Dx® tests. Additionally, data obtained via the sucrose double centrifugation method were used to evaluate the performance of the Fecal Dx® tests. Fecal samples were collected from 466 dogs aged ≥6 months from May to November 2018 (mean age = 3.7 years). Overall, eleven intestinal parasites were identified using sucrose double centrifugation. Roundworm eggs (Toxocara canis and Baylisascaris procyonis), hookworm eggs (Ancylostoma caninum and Uncinaria stenocephala), and whipworm eggs (Trichuris vulpis) were identified in 1.07% (95% confidence interval [CI] 0.38–2.56%), 5.79% (95% CI 3.85–8.31%), and 5.15% (95% CI 3.33–7.57) of samples, respectively. Using the Fecal Dx® tests, 1.07% (95% CI 0.38–2.56%), 4.29% (95% CI 2.64–6.55%), and 2.15% (95% CI 1.03–3.91) of the samples tested positive for roundworm, hookworm, and whipworm antigen, respectively. To assess the level of agreement between the Fecal Dx® tests and sucrose double centrifugation, three methods were used. Cohen's kappa indicated a fair-to-moderate level of agreement between Fecal Dx® tests and sucrose double centrifugation. In contrast, the prevalence-adjusted bias-adjusted kappa and Gwet's first-order agreement coefficient indicated almost perfect agreement between these tests, ranging from 0.87 to 0.99 among the parasites examined. This study provides valuable information on the prevalence of intestinal parasites in mature dogs in southern Ontario that will help guide parasite control recommendations for dogs in this region.

Background Human rabies remains a significant public health problem in Africa with outbreaks reported in most countries. In Nigeria–the most populous country in Africa–rabies causes a significant public health burden partly due to perennial obstacles to implementing a national prevention and control program. Methods We conducted a scoping review using standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify and select published articles from Nigeria during 1978–2020 reporting on rabies virus infections (human, canine, livestock, and wildlife), canine bites, knowledge, attitudes and practices (KAP) surveys on rabies and canine ecology studies. We extracted information on study location, year and additional details of each study such as rabies prevalence, general characteristics of offending dogs, dog vaccination status and health-seeking behaviours. Findings Between 1978 and 2020, 90 published articles met our inclusion criteria. The prevalence of rabies virus antigen detection varied between 3% and 28%, with more studies in the north. Most bites were unprovoked from dog bite studies (36.4%-97%), by dogs with low vaccination rates (12–38%). A more significant proportion of biting dogs were owned (31–90%). Laboratory confirmation for biting was available for only a small proportion of studies (6%; n = 2/32). Of the dogs surveyed during ecology studies, indigenous dogs accounted for the majority (62–98%), used mostly for security purposes (52–98%), with the vaccination rate between 15% and 38% in most states. Studies conducted in areas distant from rabies diagnostic facilities accounted for more human rabies cases and fewer dog rabies cases. Conclusion Significant improvements are necessary to achieve the elimination of human rabies mediated via dogs by 2030., Author summary Rabies remains one of the deadliest zoonoses known to humanity since antiquity, resulting in tens of thousands of human deaths each year, mostly in African and Asian countries. Mass dog vaccination, enhanced surveillance, improved access to Pre-exposure prophylaxis(PrE) and (Post-exposure prophylaxis(PEP) to at-risk groups, enforcement of responsible dog ownership and public education are keystones to rabies prevention and control. Since the first reported case in Nigeria during 1912, rabies has continued to take its toll on human and animal lives. However, gross underreporting due to a frail health care infrastructure, deficient reporting systems, and misdiagnosis with neurological diseases further complicated by socio-cultural practices have resulted in a lack of empirical data to support rabies prioritization, per the global target of 2030. We used the standard PRISMA guidelines to select Nigerian rabies studies between 1978 and 2020. Rabies risk, coupled with welfare concerns identified in this study, demonstrates the need for continued advocacy towards legislation prohibiting the dog trade in Nigeria and elsewhere. The high-risk community groups identified in this review (i.e., children, butchers, and adult males) need to be educated on response to dog bite exposure to reduce the impact of this invariable fatal but preventable disease. Moreover, there is a need for mandatory dog vaccination and implementation of a national rabies program to attain the World Health Organization (WHO) recommended vaccination coverage of at least 70%. We unravel the need to establish rabies diagnostic centres in the country’s six geopolitical zones. Local inclusion of dog bite occurrence by Disease Surveillance and Notification Officers (DSNOs), with related community surveillance tools, can help in rabies/dog surveillance. In addition, there is a need for investment into pathogen discovery by enhancing laboratory-based surveillance for wildlife rabies, understanding its potential role in Nigeria and the need for quantitative research to understand the various risk factors for disease perpetuation.

Next-generation sequencing techniques have revealed that human and animal skin is colonised by a rich and diverse population of bacteria, and that microbial composition varies between different body sites and individuals. Very little is known about the normal microbiota of healthy equine skin.To describe the taxonomic distributions of cutaneous bacterial microbiota in a population of healthy horses in Ontario, Canada, and to evaluate the effects of body site, individual and time of year on microbial diversity and community composition.Samples were collected from four body sites (dorsum, ventral abdomen, pastern and groin) from 12 clinically healthy horses from the same farm. Samples were collected from all individuals at four time points (winter, spring, summer, autumn) within a calendar year.Illumina sequencing of the V4 region of the 16S rRNA gene was performed following DNA extraction. Data were analysed using mothur software.Bacteria from 38 phyla and 1,665 genera were identified. Alpha diversity was higher in the winter and summer than spring and autumn although this was not statistically significant. Community membership and structure clustered more based on season than skin site.Healthy equine skin is inhabited by a marked diversity of microbiota. Individuals living in a similar environment share overlapping cutaneous microbial populations. These populations vary significantly over time and between body sites.Les techniques de séquençage de dernière génération ont révélé que la peau de l’homme et de l’animal est colonisée par une population riche et variée de bactéries et que la composition microbienne varie entre les différents sites corporels et entre individus. On en sait très peu sur le microbiote de la peau du cheval sain. HYPOTHÈSES/OBJECTIFS: Décrire les distributions taxonomiques du microbiote bactérien cutané d’une population de chevaux sains en Ontario, Canada et évaluer les effets du site corporel, de l’individu et de la période de l’année sur la diversité microbienne et la composition communautaire.Les échantillons ont été prélevés sur quatre sites corporels (dos, abdomen ventral, paturons et aine). De 12 chevaux cliniquement sains de la même ferme. Les échantillons ont été prélevés pour tous les individus à quatre périodes (hiver, printemps, été, automne) d’une même année. MATÉRIELS ET MÉTHODES: Le séquençage par Illumina de la région V4 du gêne 16S ARNr a été réalisé à la suite de l’extraction d’ADN. Les données ont été analysées par programme MOTHUR. RÉSULTATS: Les bactéries de 38 phyla et 1 665 genres ont été identifiées. La diversité alpha était plus élevée en hiver et été qu’au printemps et automne bien que ceci ne soit pas statistiquement significatif. L’appartenance et la structure de la communauté étaient groupées davantage à partir de la saison que du site cutané. Conclusions et importance clinique La peau de cheval sain est habituée par une diversité marquée de microbiote. Les individus vivant dans un environnement semblable partage des populations cutanées de microbiote se superposant. Ces populations varient significativement au cours du temps et entre les sites corporels.INTRODUCCIÓN: las técnicas de secuenciación de próxima generación han revelado que la piel humana y animal está colonizada por una población rica y diversa de bacterias, y que la composición microbiana varía entre diferentes lugares del cuerpo e individuos. Se sabe muy poco sobre la microbiota normal de la piel equina sana. HIPÓTESIS/OBJETIVOS: describir las distribuciones taxonómicas de la microbiota bacteriana cutánea en una población de caballos sanos en Ontario, Canadá, y evaluar los efectos de la localización corporal, el individuo y la época del año sobre la diversidad microbiana y la composición de la microflora. ANIMALES: Se recolectaron muestras de cuatro zonas del cuerpo (dorso, abdomen ventral, cuartilla e ingle) de 12 caballos clínicamente sanos de la misma granja. Se obtuvieron muestras de todos los individuos en cuatro momentos (invierno, primavera, verano, otoño) en un año de calendario. MÉTODOS Y MATERIALES: se realizó la secuenciación de Illumina de la región V4 del gen de RNAr 16S después de la extracción de DNA. Los datos se analizaron con el software MOTHUR. RESULTADOS: se identificaron bacterias de 38 phyla y 1,665 géneros. La diversidad alfa fue mayor en invierno y verano que en primavera y otoño, aunque esto no fue estadísticamente significativo. La diversidad y la estructura de la comunidad se agruparon más según la estación que la localización de la piel. CONCLUSIONES E IMPORTANCIA CLÍNICA: La piel sana de equinos está habitada por una marcada diversidad de microbiota. Los individuos que viven en un entorno similar comparten poblaciones microbianas cutáneas superpuestas. Estas poblaciones varían significativamente con el tiempo y entre los sitios del cuerpo.Die Next-Generation-Sequencing Techniken haben gezeigt, dass die menschliche wie auch die tierische Haut von einer reichen und diversen Bakterienpopulation kolonisiert wird und dass die mikrobielle Zusammensetzung zwischen den unterschiedlichen Körperstellen und den Individuen variiert. Es ist sehr wenig bekannt über das normale Mikrobiom der gesunden Pferdehaut.Die Beschreibung der taxonomischen Verteilung der kutanen bakteriellen Mikrobiome in einer gesunden Pferdepopulation in Ontario, Kanada, sowie die Evaluierung der Einflüsse von Körperstellen, Individuen und Jahreszeit auf die mikrobielle Diversität und Zusammensetzung.Bei 12 klinisch gesunden Pferden derselben Farm wurden Proben von vier Körperstellen genommen (Rücken, ventrales Abdomen, und Sprunggelenke und Leiste). Es wurden von allen Individuen zu vier Zeitpunkten (Winter, Frühling, Sommer, Herbst) innerhalb eines Kalenderjahres Proben genommen.Illumina Sequenzierung der V4 Region des 16S rRNA Gens wurde nach DNA Extraktion durchgeführt. Die Daten wurden mittels MOTHUR Software analysiert.Bakterien von 38 Phyla und 1.665 Genera wurden identifiziert. Die Alpha Diversität war im Winter und Sommer höher als im Frühling und im Herbst, obwohl dies nicht statistisch signifikant war. Die Community Mitgliedschaft und Struktur trat je nach Saison, nicht aber Körperstelle, gehäuft auf.Gesunde Pferdehaut wird von deutlich unterschiedlichen Mikrobiota bewohnt. Individuen, die in einer ähnlichen Umgebung wohnen, teilen diese kutanen Mikrobiota. Diese Populationen variieren mit der Zeit und zwischen Körperstellen signifikant.背景: 次世代シーケンシング技術により、ヒトや動物の皮膚には豊富で多様な細菌群が生息しており、微生物の構成は身体の部位や個人によって異なることが明らかになった。健常馬の皮膚の正常な微生物叢についてはほとんど知られていない。 仮説・目的: 本研究の目的は、カナダ・オンタリオ州の健常馬集団における皮膚細菌微生物叢の分類学的分布を明らかにし、体の部位、個体、時期が微生物の多様性および群集組成に及ぼす影響を評価することであった。 供試動物-同: 牧場の臨床的に健常な馬12頭の4部位 (背、腹、前脚、鼠径部) からサンプルを採取した。サンプルは、1暦年内の4時点 (冬、春、夏、秋) ですべての個体から採取した。 材料と方法: 16S rRNA遺伝子のV4領域のイルミナシークエンス法を、DNA抽出後に実施した。データはMOTHURソフトウェアを用いて解析した 結果: 38門、1,665属の細菌が同定された。α多様性は、春と秋よりも冬と夏の方が高かったが、これは統計的には有意ではなかった。群集の構成および構造は、皮膚の部位よりも季節に基づいてクラスター化していた。 結論と臨床上の重要性: 健常馬の皮膚には、顕著な多様性を持った微生物が生息している。同じような環境で生活している個体は、皮膚の微生物集団が重複している。これらの個体群は、時間の経過とともに、また体の部位間で大きく変化する。.背景-新: 代测序技术揭示了人类和动物皮肤被丰富多样的细菌群定植, 并且不同身体部位和个体之间的微生物组成不同。对健康马皮肤的正常微生物群知之甚少 假设/目的: 描述加拿大安大略省健康马种群中皮肤细菌微生物区系的分类分布, 并评价身体部位、个体和一年中的时间对微生物多样性和群落组成的影响。 动物-从同: 农场的12匹临床健康马的4个身体部位 (背部、腹侧腹部、胸骨和腹股沟) 采集样本。在一个日历年内的4个时间点 (冬季、春季、夏季、秋季) 采集所有个体的样本。 方法和材料: DNA提取后对16S rRNA基因V4区进行Illumina测序。使用Mothur软件分析数据。 结果: 鉴定出38个门和1665个属的细菌。冬季和夏季的α多样性高于春季和秋季, 但无统计学意义。微生物种类和聚集结构更多地基于季节而不是皮肤部位。 结论和临床重要性: 健康马皮肤的微生物区系定植呈现着显著多样性。生活在相似环境中的个体, 其皮肤微生物种群具有相似性。这些微生物群随时间和身体部位发生着显著变化。.As técnicas de sequenciamento de última geração demonstraram que a pele humana e animal é colonizada por uma população rica e diversa de bactérias e que a composição microbiana varia entre diferentes áreas corpóreas e indivíduos. Muito pouco se sabe sobre a microbiota normal da pele equina saudável. HIPÓTESE/OBJETIVOS: Descrever as distribuições taxonômicas da microbiota cutânea bacteriana em uma população de cavalos saudáveis em Ontário, Canadá, e avaliar os efeitos da topografia corpórea, indivíduo e época do ano na diversidade microbiana e composição da comunidade.As amostras foram coletadas de quatro áreas corpóreas (dorso, abdômen ventral, quartelas e virilha) de 12 cavalos clinicamente saudáveis da mesma fazenda. As amostras foram coletadas de todos os indivíduos em quatro tempos experimentais (inverno, primavera, verão, outono) dentro de um ano civil. MÉTODOS E MATERIAIS: O sequenciamento Illumina da região V4 do gene 16S rRNA foi realizado após a extração do DNA. Os dados foram analisados usando o software MOTHUR.Foram identificadas bactérias de 38 filos e 1.665 gêneros. A alpha-diversidade foi maior no inverno e verão do que na primavera e no outono, embora isso não tenha sido estatisticamente significativo. As relações filogenéticas e a estrutura da comunidade se agruparam de acordo com a estação do ano do que com a topografia corpórea. CONCLUSÕES E IMPORTÂNCIA CLÍNICA: A pele saudável dos equinos é habitada por microbiota bastante diversa. Indivíduos que vivem em um ambiente semelhante compartilham populações microbianas cutâneas sobrepostas. Essas populações variam significativamente ao longo do tempo e entre as áreas corpóreas.

Several factors are known to affect the intestinal microbiota of cattle. However, how these changes occur over time is poorly understood. This study aimed to investigate the consequences of entrance into a feedlot and the effects of virginiamycin used as a growth promoter on the bovine fecal microbiota. Two batches of beef cattle (B1, n = 50 and B2, n = 36) entering a feedlot operation were randomly divided into two pens: one receiving virginiamycin and one group not receiving antibiotic (control group). Fecal samples were collected at arrival, mid feedlot and at exit to slaughter. The V4 region of 16S rRNA gene was amplified and sequenced. Escherichia coli strains isolated in samples from arrival and exit of B2 were also isolated and used as indicators of antimicrobial susceptibility. Marked changes in membership and structure of fecal microbiota occurred following entrance into the feedlot. At mid feedlot, virginiamycin affected bacterial community membership, but not structure, suggesting that the antibiotic had a stronger effect on the rare, but not on the most abundant species. The use of virginiamycin had no demonstrable effect on antibiotic resistance in E. coli. The differences found between batches are suggestive that variations in study conditions are important and can strongly affect the intestinal microbiota.

OBJECTIVE To determine whether passive ureteral dilation (PUD) would occur after an indwelling ureteral stent was left in place in healthy dogs for 2 or 6 weeks, ureteroscopy would be possible at the time of stent removal, and PUD would be reversible after stent removal. ANIMALS 5 healthy adult female Beagles. PROCEDURES A ureteral stent was cystoscopically placed in each ureter of each dog with fluoroscopic guidance (week 0). One stent was removed from 1 ureter in each dog after 2 weeks (ureter group 1), and the other was removed after 6 weeks (ureter group 2); removal timing was randomized. Computed tomographic excretory urography was performed every 2 weeks from weeks 0 through 10 to measure ureteral diameters. Ureteroscopy was attempted at the time of ureteral stent removal in each group. Ureteral diameters were compared among measurement points. RESULTS The degree of PUD was significant after 2 and 6 weeks of stent placement in both ureter groups. Mean diameter of the midportion of the ureter in both groups prior to stent placement was 1.70 mm (range, 1.3 to 2.7 mm). At stent removal, mean diameter of the midportion of the ureter was 2.86 mm (range, 2.4 to 3.1 mm) in group 1 and 2.80 mm (range, 2.1 to 3.4 mm) in group 2. Ureteroscopy was successfully performed in all dogs up to the renal pelvis. Compared with week 0 values for diameter of the midportion of the ureter, the degree of PUD induced by stent placement had reversed by week 8 in group 1 (mean diameter, 2.00 mm [range, 1.5 to 2.3 mm]). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ureteral stent placement for 2 weeks would result in sufficient PUD in healthy dogs to allow ureteroscopy at the time of stent removal and that the original ureteral diameter would eventually be restored. Additional research is needed to determine whether findings would be similar for dogs with urinary tract disease.