On-farm biosecurity measures are an important part of a control plan to minimize the introduction and spread of infectious diseases, such as equine influenza, in an equine facility. It can be challenging, however, to evaluate the efficacy of biosecurity measures under field conditions. We used an agent-based computer simulation model to describe the impact of: i) preventive vaccination; ii) reduced horse-to-horse contact; and iii) a combination of vaccination and reduced contact during an outbreak of equine influenza in a simulated horse facility. The model demonstrated that the most effective intervention was a combination of a high proportion of recently vaccinated horses and a substantial reduction in horse-to-horse contact once equine influenza had been identified in the facility. This study highlights the importance of compliance when implementing biosecurity measures, such as facility-level infection control practices, on horse farms.

Poultry has been identified as a reservoir of foodborne enteric pathogens and antimicrobial resistant bacteria. The objective of this study was to describe and compare antimicrobial resistant isolates from an Ontario broiler chicken farm-level baseline project (2003 to 2004) to the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) Ontario abattoir and retail surveillance data from 2003, and to the most recent (2015) CIPARS Ontario chicken surveillance data in order to assess the impact of an industry-wide policy change in antimicrobial use. Ceftiofur resistance (TIO-R) prevalence in Salmonella decreased by 7% on farm between 2003 and 2004 and 2015. During the same timeframe, TIO-R E. coli prevalence decreased significantly by 16%, 11%, and 8% in farm, abattoir, and retail samples, respectively. Gentamicin resistant (GEN-R) E. coli, however, increased by 10% in farm and 15% in retail-derived isolates, and trimethoprim-sulfamethoxazole resistant (TMSm-R) E. coli increased significantly by 20%, 18%, and 5% in farm, abattoir, and retail isolates, respectively. Similarly, ciprofloxacin-resistant (CIP-R) Campylobacter spp. significantly increased in retail isolates by 11% and increased in farm (33%) and abattoir isolates (7%). The decrease in TIO-R Salmonella/E. coli in recent years is consistent with the timing of an industry-led intervention eliminating the preventive use of ceftiofur, a third generation cephalosporin and class of antimicrobials deemed critically important to human medicine. The rise in GEN-R and TMSm-R prevalence is indicative of recent shifts in antimicrobial use. Our study highlights the importance of integrated surveillance in detecting emerging trends and determining the efficacy of interventions to improve food safety.

OBJECTIVE To determine from MRI measurements whether soft palate length (SPL) and thickness are correlated in dogs, evaluate the association between the olfactory bulb angle (OBA) and degree of brachycephalia, and determine the correlation between soft palate–epiglottis overlap and OBA in dogs. ANIMALS 50 brachycephalic and 50 nonbrachycephalic client-owned dogs without abnormalities of the head. PROCEDURES Medical records and archived midsagittal T2-weighted MRI images of brachycephalic and nonbrachycephalic dogs' heads were reviewed. Group assignment was based on breed. Data collected included weight, SPL and thickness, OBA, and the distance between the caudal extremity of the soft palate and the basihyoid. Soft palate length and thickness were adjusted on the basis of body weight. RESULTS Brachycephalic dogs had significantly thicker soft palates and lower OBAs, compared with findings for nonbrachycephalic dogs. There was a significant negative correlation (r2 = 0.45) between OBA and soft palate thickness. The correlation between SPL and OBA was less profound (r2 = 0.09). The distance between the caudal extremity of the soft palate and the basihyoid was shorter in brachycephalic dogs than in nonbrachycephalic dogs. The percentage of epiglottis–soft palate overlap significantly decreased with increasing OBA (r2 = 0.31). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that MRI images can be consistently used to assess anatomic landmarks for measurement of SPL and thickness, OBA, and soft palate-to-epiglottis distance in brachycephalic and nonbrachycephalic dogs. The percentage of epiglottis–soft palate overlap was significantly greater in brachycephalic dogs and was correlated to the degree of brachycephalia.

OBJECTIVE To compare the efficacy of application of an alcohol-based antiseptic (80% ethyl alcohol) hand rub (ABAHR) with that of a 2% chlorhexidine gluconate scrub (CGS2) for immediate reduction of the bacterial population on the skin of dogs. ANIMALS 50 client-owned dogs with no evidence of skin disease. PROCEDURES On each dog, 2 areas of hair on the ventral aspect of the abdomen were clipped with a No. 40 blade and cleared of debris. A direct contact plate holding tryptic soy agar with polysorbate 80 and lecithin was gently pressed (for 2 seconds) on each skin site (preapplication sample). The CGS2 and ABAHR were each aseptically applied to 1 skin site on each dog. A direct contact plate was subsequently applied to each site in a similar manner (postapplication sample). All plates were cultured, and bacterial isolates were identified and quantified by the number of CFUs per plate. RESULTS Application of the CGS2 and ABAHR significantly decreased skin bacterial colony counts, compared with findings for preapplication samples. The number of CFUs per plate or postapplication percentage reduction in CFUs per plate did not differ between treatments. There were no adverse skin reactions associated with either application. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that applications of ABAHR and CGS2 were equally effective at immediately reducing the bacterial population on the skin of dogs, and there was no significant difference in percentage reduction in colony counts between the 2 applications.

OBJECTIVE To evaluate the microbial integrity of preservative-free cyclodextrin-based alfaxalone in a multiple-use system. SAMPLE 22 vials of preservative-free alfaxalone. PROCEDURES 2 storage conditions (room temperature, 22°C; refrigerated temperature, 4°C) and 3 handling techniques (closed system transfer device, nonclosed dispensing pin, and manufacturer-supplied vial stopper) comprised 6 treatment groups (3 replicates/group). An aliquot (0.5 mL) was withdrawn from each vial daily for 14 days. Samples were immediately inoculated into tryptic soy broth and incubated at 36°C for 24 hours; samples were subcultured onto 5% Columbia sheep blood agar and incubated for 48 hours. Isolated colonies were evaluated for identification. RESULTS There was no evidence of microbial contamination of vials stored for 7 days in refrigeration and handled with a protected port (closed system transfer device or nonclosed dispensing pin). CONCLUSIONS AND CLINICAL RELEVANCE The US FDA prohibits the use of alfaxalone beyond 6 hours after the vial stopper is broached (punctured), as mandated for a preservative-free injectable medication. Findings for the study reported here supported the use of alfaxalone for 7 days when refrigerated and handled with a single puncture of the stopper by use of a protected port (closed system transfer device or nonclosed dispensing pin). This would appear to be a practical alternative for an injectable anesthetic. It would minimize drug waste and the subsequent environmental impact for disposal of unused drug and allow standardization of storage and handling protocols for alfaxalone use in veterinary practices across the United States.

OBJECTIVE To evaluate gene transfer of recombinant adeno-associated viral (rAAV) vectors with AAV2 or AAV5 capsid and encoding hyaluronic acid (HA) synthase-2 (HAS2) into joints of healthy dogs. ANIMALS 22 purpose-bred Beagles. PROCEDURES Plasmid expression cassettes encoding canine HAS2 (cHAS2) were assessed in vitro for concentration and molecular size of secreted HA. Thereafter, rAAV2-cHAS2 vectors at 3 concentrations and rAAV5-cHAS2 vectors at 1 concentration were each administered intra-articularly into the left stifle joint of 5 dogs; 2 dogs received PBS solution instead. Synovial fluid HA concentration and serum and synovial fluid titers of neutralizing antibodies against AAV capsids were measured at various points. Dogs were euthanized 28 days after treatment, and cartilage and synovium samples were collected for vector DNA and mRNA quantification and histologic examination. RESULTS Cell transfection with plasmids encoding cHAS2 resulted in an increase in production and secretion of HA in vitro. In vivo, the rAAV5-cHAS2 vector yielded uniform genome transfer and cHAS2 expression in collected synovium and cartilage samples. In contrast, rAAV2-cHAS2 vectors were detected inconsistently in synovium and cartilage samples and failed to produce clear dose-related responses. Histologic examination revealed minimal synovial inflammation in joints injected with rAAV vectors. Neutralizing antibodies against AAV capsids were detected in serum and synovial fluid samples from all vector-treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE rAAV5-mediated transfer of the gene for cHAS2 into healthy joints of dogs by intra-articular injection appeared safe and resulted in vector-derived cHAS2 production by synoviocytes and chondrocytes. Whether this treatment may increase HA production by synoviocytes and chondrocytes in osteoarthritic joints remains to be determined.

OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and 3 cone-beam CT (CBCT) methods for the identification of predefined anatomic landmarks in brachycephalic dogs. ANIMALS 19 client-owned brachycephalic dogs admitted for evaluation and treatment of dental disease. PROCEDURES 26 predefined anatomic landmarks were evaluated separately by use of the RAD method and 3 CBCT software modules (serial CBCT slices and custom cross sections, tridimensional rendering, and reconstructed panoramic views). A semiquantitative scoring system was used, and mean scores were calculated for each anatomic landmark and imaging method. The Friedman test was used to evaluate values for significant differences in diagnostic yield. For values that were significant, the Wilcoxon signed rank test was used with the Bonferroni-Holm multiple comparison adjustment to determine significant differences among each of the 6 possible pairs of diagnostic methods. RESULTS Differences of diagnostic yield among the Rad and 3 CBCT methods were significant for 19 of 26 anatomic landmarks. For these landmarks, Rad scores were significantly higher than scores for reconstructed panoramic views for 4 of 19 anatomic landmarks, but Rad scores were significantly lower than scores for reconstructed panoramic views for 8 anatomic landmarks, tridimensional rendering for 18 anatomic landmarks, and serial CBCT slices and custom cross sections for all 19 anatomic landmarks. CONCLUSIONS AND CLINICAL RELEVANCE CBCT methods were better suited than dental radiography for the identification of anatomic landmarks in brachycephalic dogs. Results of this study can serve as a basis for CBCT evaluation of dental disorders in brachycephalic dogs.

OBJECTIVE To assess and compare 2 injection techniques for conducting ocular anterior segment indocyanine green angiography (ASICGA) and sodium fluorescein (SF) angiography in horses. ANIMALS 3 healthy adult female horses (age range, 19 to 25 years). PROCEDURES Horses were sedated, jugular catheters were placed, and manual restraint was used to ensure proper positioning for the angiography procedure. Two injection techniques (IV and intra-arterial) were performed for each horse 1 week apart. Intravenous injections of 0.25% indocyanine green (ICG; 50 mg) and 10% SF (10 mg/kg) were administered via the jugular catheter. Intra-arterial injections of ICG (1 mg) and SF (1 mg/kg) were administered into the common carotid artery with ultrasound guidance. Angiography was performed by use of an adaptor system comprised of a modified digital single-lens reflex camera, camera adaptor, and lens. Imaging was performed at a rate of 3 images/s for 60 seconds immediately following ICG injection, then at 2, 3, 4, and 5 minutes after injection. The SF was injected 5 minutes thereafter. RESULTS ASICGA allowed visual identification of the arterial, capillary, and venous phases of angiography. Intra-arterial administration provided superior dye fluorescence, sharper contrast, and faster dye passage than IV administration. Visibility of the iris vasculature was limited with SF, and extravasation of SF was noted. No clinically important adverse events were detected. CONCLUSIONS AND CLINICAL RELEVANCE ASICGA images were obtainable with both injection techniques; however, visibility of the iris vasculature was better with intra-arterial administration of ICG. The ASICGA technique may serve as a viable ocular imaging modality for horses.

OBJECTIVE To characterize the MRI and histologic features of the supraspinatus tendon in nonlame dogs. ANIMALS 7 cadavers (14 shoulder joints) of nonlame 2-year-old sexually intact male Beagles. PROCEDURES Multiple MRI fluid-sensitive pulse sequences were obtained for both shoulder joints of each cadaver, and the thickness, volume, and signal intensity of each supraspinatus tendon were assessed. After MRI scanning was complete, the shoulder joints were processed for histologic examination. Tissue specimens were stained with various stains to determine tendon morphology and composition. Histologic and MRI findings were correlated and described. RESULTS All supraspinatus tendons had a trilaminar appearance on sagittal and transverse MRI images, which was characterized by a thick, hyperintense center layer (central substance) sandwiched between thin hypointense superficial and deep margins. The mean ± SD central substance-to-superficial margin and central substance-to-deep margin thickness ratios were 8.4 ± 1.2 and 9.0 ± 0.9, respectively; supraspinatus tendon-to-triceps brachii muscle signal intensity ratio was 1.3 ± 0.2; and tendon volume was 445 ± 20 mm3. The superficial and deep margins histologically resembled other tendons with highly ordered collagen fibers. The central substance was comprised of water-rich glycosaminoglycans interspersed among haphazardly arranged collagen bundles. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated histologically normal canine supraspinatus tendons have a trilaminar appearance on MRI images. In dogs, a diagnosis of supraspinatus tendinosis should not be based solely on the tendon having a hyperintense signal on MRI images; other MRI evidence of shoulder joint disease and diagnostic findings are necessary to support such a diagnosis.

Salmonella enterica serovar Typhimurium has a wide host range and is capable of causing infections ranging from severe gastroenteritis to systemic infection in humans. To determine if attenuated S. Typhimurium strains can serve as safe and effective oral vaccines to prevent typhoid fever, the biologic characteristics of crp and sipB deletion mutants were evaluated. Previous studies had found that the crp and sipB genes are related to Salmonella pathogenicity. In this study, cytotoxicity, protective efficacy, and immune responses of the host were analyzed. Our previous data had shown a significance decrease in virulence for the crp and sipB mutants compared with a wild-type strain. The current study confirmed this finding in HeLa cells and showed that the crp mutant was significantly less cytotoxic (P < 0.05) than the sipB mutant. Mice vaccinated with the crp mutant showed significantly better protection after challenge with the wild-type strain (P < 0.05) and significantly greater responses in serum IgG (P < 0.01) and secretory IgA (P < 0.05) compared with the mice vaccinated with the sipB mutant (P < 0.05). Our results indicate that the crp mutant has the potential to be a vaccine candidate and is safe in mice.