Table of Contents and Abstracts

Streptococcus suis (S. suis) and Glaesserella parasuis (G. parasuis) are ubiquitous colonizers of swine tonsils that can cause systemic disease and death, under undefined conditions. It is not known, however, whether these 2 species interact during initial infection. To investigate whether such interactions occur, the objective of this study was to assess phenotypic differences between mono- and co-cultures of S. suis and G. parasuis when representative strains with different virulence potential were co-cultured in vitro. In cross-streak screening experiments, some G. parasuis (GP) serovar strains (GP3, GP4, GP5) exhibited altered morphology with some S. suis (SS) serovar strains, such as SS2, but not with SS1. Co-culture with GP5 reduced hemolytic activity of SS1, but not of SS2. Although both SS strains outgrew GP isolates in biofilm co-cultures, strain type affected the number of planktonic or sessile cells in co-culture biofilms. Numbers of sessile SS1 increased in co-cultures, but not of GP3. Both planktonic and sessile SS2 increased in co-culture, whereas GP5 decreased. Sessile SS1 increased, but planktonic GP5 decreased in co-culture and planktonic SS2 increased, but sessile GP3 decreased when grown together. The SS2 strain had a competitive advantage over GP3 during mid-exponential co-culture in broth. Streptococcus suis is predicted to use more unique carbon sources, suggesting that S. suis outcompetes G. parasuis in growth and nutrient consumption. This work provides direction for future studies of phenotypic and genotypic interactions between these and other swine tonsil co-colonizers.

Twelve adult horses were randomly assigned to 2 groups in a prospective experimental trial. A pneumatic tourniquet (425 mmHg) was placed, under sedation, proximal to the carpus on one randomly chosen thoracic limb. A cephalic vein catheter was placed distal to the tourniquet to establish an intravenous regional limb perfusion technique (IVRLP) with morphine (0.1 mg/kg) diluted with saline 0.9% to 0.1 mL/kg, and the tourniquet left in place for 30 minutes. Horses were euthanized at 1 h (Group I) or 6 h (Group II) following the IVRLP and synovial fluid from the radiocarpal, intercarpal, metacarpophalangeal, distal interphalangeal, and digital flexor tendon sheath was obtained from the injected and contralateral (control) limb immediately after. Morphine concentrations were determined using liquid chromatography-mass spectrometry. An unpaired t-test was used to compare morphine concentrations from both groups (P < 0.05). Synovial morphine concentrations were detected in the injected limb in all horses in Group I, except in one horse in the radiocarpal joint, and detected in 5 of 6 horses in Group II. Mean synovial concentrations ranged between 301.8 ± 192.3 and 608 ± 446.6 ng/mL in Group I and between 27.0 ± 17.7 and 136.8 ± 103.6 ng/mL in Group II and were significantly higher in Group I between paired anatomical sites of both groups for the radiocarpal and distal interphalangeal joints, and the digital flexor tendon sheath. In conclusion, concentrations of morphine after IVRLP can be detected in synovial fluid distal to the tourniquet at 1 and 6 hours in horses.

Interstitial glucose monitoring systems are commonly being used in diabetic dogs. The aim of this study was to document the incidence of complications associated with the use of a flash glucose monitoring system (FGMS) in dogs. Medical records of dogs that had placement of a 14-day FGMS during a 1-year period were reviewed. Data retrieved included the number of days the sensor remained attached and functional, sensor detachment, sensor failure prior to the end of the 14-day monitoring period, and dermatologic changes at the sensor site. Descriptive statistics were used to characterize the data. Thirty-four dogs had FGMSs placed. Most [32/34 (94%)] sensors were placed over the dorsolateral aspect of the thorax caudal to the scapula. Twenty-four sensors (71%) remained attached for the full 14 days. Incidence of complications associated with FGMS use was 13/34 (38%). The most frequent complication was mild dermatologic changes at the sensor site [6/34 (18%)]. Erythema and crusting at the attachment site were common and could be related to contact dermatitis, hypersensitivity, or skin preparation prior to placement. Flash glucose monitoring systems are safe in dogs, although there are some potential complications that should be discussed with dog owners.

This prospective clinical study sought to determine the accuracy of cytopathologic examination and needle-core biopsy (NCB) against diagnoses obtained by excisional histopathology (EH) for canine splenic masses. Twenty-five masses were evaluated ex vivo by ultrasound-guided fine-needle aspiration (FNA) and NCB tissue sampling. Each spleen was placed in a container and artificial skin placed over its surface. Ultrasound-guided FNA using a 22-gauge needle and 2 NCB samples [14-gauge (NCB-14), 16-gauge (NCB-16)] were obtained and submitted for analysis. Results were compared to results obtained by splenic excisional histopathology (EH). There was no difference noted between FNA, NCB-14, or NCB-16 analyses. In addition, there was no difference in accuracy between FNA and NCB-14 or between FNA and NCB-14 versus NCB-16. Reported accuracy of FNA was 0.72, NCB-14 was 0.72, and NCB-16 was 0.64, respectively. Both FNA and NCB-14 displayed a sensitivity of 71% and NCB-16 a sensitivity of 53%. Both FNA and NCB-14 displayed a specificity of 75% and NCB-16 a specificity of 88%. The results demonstrated that NCB had no advantage clinically over FNA at diagnosing splenic pathology. This study further demonstrates that preoperative diagnostic evaluation of the spleen is not highly accurate and cannot be recommended prior to splenectomy.

A 6-month-old, intact female, French bulldog was presented to the Emergency Department for evaluation of vomiting and diarrhea over the preceding week which had not responded to supportive medical therapy. Imaging studies identified an incarcerated para-esophageal hernia with peritoneal effusion and gas consistent with gastrointestinal perforation. Following stabilization, the dog underwent an exploratory laparotomy which confirmed an incarcerated hiatal hernia and gastric perforation. A gastrectomy was performed to repair the defect, and to prevent recurrence both a herniorrhaphy and esophagopexy were performed. Post-operative care required treatment for septic shock including vasopressor and hydrocortisone infusions and plasma transfusions for colloidal support. The patient was successfully discharged 4 days after surgery. The histopathology results identified spiral bacteria consistent with Helicobacter spp. which was subsequently treated with oral antibiotics and a proton pump inhibitor. The dog has had no further gastrointestinal signs in the 90 days since surgery.

Gastric perforation and peritonitis can occur secondary to an incarcerated esophageal hiatal hernia, and if treated promptly can result in a successful outcome. This case demonstrates a novel etiology of gastric perforation which may be associated with brachycephalic breeds.

The objective of this retrospective study was to report the overall peri-operative complications and short- to long-term outcomes of subtotal ear canal ablation and lateral bulla osteotomy in French bulldogs with otitis media. Medical records from 2018 to 2021 were reviewed for preoperative neurological signs, surgical technique, postoperative complications, and long-term outcomes. Postoperative complications, such as a head tilt, nystagmus, ataxia, facial nerve dysfunction, as well as skin or wound infection, were recorded. Eighteen client-owned dogs (20 ears) were included in the study. Postoperative complications were observed in 5/18 dogs (6/20 ears) with 2 of them being considered major complications. Referring veterinarians and owner telephone follow-up (mean: 33 mo, range: 17 to 56 mo) were obtained for all patients. Total recovery was reported in 9/18 dogs (11/20 ears) with a postoperative improvement of the vestibular signs and facial nerve paresis within 8 wk. All dogs maintained the pinnas’ natural, erect morphology, and movement.

Little is known about the perioperative complications and treatment outcomes of repairing perineal hernias using semitendinosus muscle transposition (SMT) in small-breed dogs. The objective of this study was to retrospectively evaluate the complications and prognosis of perineal hernia repair using SMT in 33 small, male dogs (weighing < 15 kg). Before the study began, the medical records of all small-breed dogs that underwent SMT from March 2013 to June 2022 at the Veterinary Medical Center, University of Tokyo were analyzed, and telephone interviews were conducted with their owners or referring physicians. Short-term complications were observed in 42.4% of the patients. Lameness was the most common complication, although all cases were resolved within a few days. The recurrence rate during the study period (median: 265 d) was 9.1%. The results of this study showed that transposition of the semitendinosus muscle is more invasive than other surgical procedures for perineal hernias. It is, however, an effective alternative when repair with internal obturator muscle transposition alone is expected to be difficult, such as severe atrophy of the internal obturator muscle or herniation in the ventral direction, and in cases with a history of surgery by transposition of the internal obturator muscle.

Cranial cruciate ligament (CCL) disease is the leading cause of canine lameness. Diagnosis is based on physical examination and diagnostic imaging findings. Limitations of diagnostic modalities, including patient temperament, cost, availability, and need for general anesthesia, preclude their use for many patients. Infrared thermography is an easy, non-invasive diagnostic screening technique with use in both human and veterinary musculoskeletal conditions. The objective of this study was to investigate the utility of infrared thermography to diagnose CCL disease in a large population of client-owned dogs and investigate for correlations between ability of thermography to diagnose CCL deficiency and recorded explanatory factors. A commercial grade thermal imaging camera was used to collect preoperative images of both stifles in 50 dogs with surgically confirmed CCL rupture in one stifle and a normal opposite stifle. The average maximum temperatures of the affected and unaffected stifles were collected from these images and used for statistical analysis. Infrared thermography was not successful in differentiating between CCL-deficient and unaffected stifles in this cohort. No significant differences in average maximal temperature were observed between stifles when comparing to explanatory factors or variables. Use of infrared thermography should not be relied upon to diagnose canine CCL disease.

The purpose of this experimental study was to determine the cross-protection of a new trivalent vaccine containing porcine circovirus types 2a/b (PCV-2a/b) and Mycoplasma hyopneumoniae. Pigs were vaccinated intramuscularly at 21 days of age, then challenged at 42 days of age with a dual PCV-2e and M. hyopneumoniae challenge. Growth performance was significantly improved during the experimental period (21 to 63 days of age) in vaccinated-challenged pigs compared to unvaccinated-challenged pigs. Pigs that were vaccinated and challenged elicited a significant amount of PCV-2e- and M. hyopneumoniae-specific interferon-γ secreting cells (IFN-γ-SC) and reduced the levels of PCV-2e viremia and laryngeal shedding. The results of the present study demonstrated that a trivalent vaccine provided cross-protection against a dual PCV-2e and M. hyopneumoniae challenge.

Respiratory disease is one of the main diseases of sheep in many regions globally. Respiratory syncytial virus (RSV) causes severe disease in humans and in calves, but little is known about the role of RSV in sheep. We studied the prevalence of ovine RSV in sheep processed at 5 abattoirs in southern Australia. Bronchial swab samples were collected from 182 consignments of lambs up to 12 months of age and 71 consignments of adult sheep; these were tested for the presence of the virus using a qPCR based on the F gene sequence. Six of the 253 abattoir consignments (2.4%) tested positive for ovine RSV. Four of the positive consignments were lambs and 2 were adult sheep. To our knowledge, this is the first report of the ovine strain of RSV in sheep with pneumonia from Australia. Further research is needed to clarify the role of RSV in pneumonia in sheep.