Pathophysiological and immune cell responses in calves prior to and following lung challenge with formalin-killed Pasteurella multocida biotype A:3 and protection studies involving subsequent homologous live challenge

Pneumonic pasteurellosis is a common respiratory infection in cattle that has major economic and welfare implications world-wide and the incidence in the UK due to Pasteurella multocida, currently the same as that associated with Mannheimia haemolytica, is increasing. Whereas much is known regarding the pathogenesis of M. haemolytica infections little information is available on the pathogenic process of pasteurellosis initiated by P. multocida. In the present work calf systemic and innate immune responses to intratracheal challenge with formalin-killed P. multocida biotype A:3 and to subsequent experimental lung infection with live P. multocida were investigated. Eight-week-old calves were challenged intratracheally on day 0 with either 10⁹ colony forming units (cfu) of formalin-killed P. multocida biotype A:3 in 300 ml saline (n=10) or 300 ml saline alone (n=10), followed, at day 21, by challenge with 10⁹ cfu live P. multocida. Pathophysiological and lung phagocyte responses were assessed by clinical monitoring, sequential lung lavage and blood sampling. Results for samples obtained before, during and after challenge showed clinical and acute phase protein responses to both bacterial culture and saline control treatments, although higher responses were associated with bacterial challenge. Phagocytosis of P. multocida during 1 h incubation periods with lavaged cells in vitro was unaffected by exposure in vivo to killed P. multocida and there was evidence that P. multocida was able to survive intracellularly during this assay. There was no indication that lung exposure to formalin-killed P. multocida conferred protection against subsequent homologous live challenge.     

Physiologic effects of furosemide in combination with water restriction when administered at 4 and 24 hours prior to high-intensity treadmill training

Although controversial, due to its reported effectiveness in attenuating bleeding associated with exercise-induced pulmonary hemorrhage (EIPH), furosemide is currently a permitted race day medication in most North American racing jurisdictions. The objective of this study was to assess the efficacy of furosemide in reducing the presence and severity of EIPH when administered 24 hr prior to strenuous treadmill exercise. Eight exercised Thoroughbred horses received saline or 250 mg of furosemide either 4 or 24 hr prior to high-speed treadmill exercise in a balanced 3-way cross-over design. Blood samples were collected for determination of furosemide, lactate, hemoglobin, blood gas, and electrolyte concentrations. Heart rate and pulmonary arterial pressure were measured throughout the run and endoscopic examination and bronchoalveolar lavage (BAL) performed. Horses were assigned an EIPH score and the number of red blood cells in BAL fluid determined. Although not significantly different, endoscopic EIPH scores were lower in the 4-hr versus the 24-hr and saline groups. RBC counts were not significantly different between the treatment groups. Pulmonary arterial pressures were significantly increased at higher speeds; however, there were no significant differences between dose groups when controlling for speed. A small sample size and unknown bleeding history warrant a larger-scale study.     

Inferomedial placement of a single-entry subpalpebral lavage tube for treatment of equine eye disease

The objective of this study was to describe method of placement, and frequency and severity of complications associated with a subpalpebral lavage system placed in the medial aspect of the equine inferior eyelid. The inferomedial subpalpebral lavage (ISPL) tube is positioned deep in the medial aspect of the inferior conjunctival fornix so that the footplate lies flat between the lower eyelid and the anterior surface of the nictitans. Retrospective data from the placement of 92 ISPL systems placed in 86 horses during a 31-month period were examined. Tube placement was performed using sedation and regional anesthesia only in 59% of horses. The median duration of tube placement was 19 days (range: 1-61 days). Seventy-one horses were treated for up to 55 days following discharge from hospital with an ISPL tube in place. No complications were reported with 59% of ISPL systems. Non-ocular complications were found in 38% of ISPL systems and included tube displacement from the conjunctival fornix (18%), suture loss requiring resuturing of the system to the horse's head (14%), and damage necessitating replacement of the injection port (6%). Ocular complications were recorded in 3% of horses and were limited to inferior eyelid swelling. Vision was retained in 88% of horses. The ISPL system is easily and safely placed, and well tolerated for extended periods. It appears to be associated with infrequent and minor complications when compared with placement of subpalpebral lavage tubes in the superior eyelid.     

Acremonium strictum pulmonary infection in a horse

A 10-year-old Thoroughbred gelding was admitted to the Veterinary Medical Teaching Hospital of the University of California-Davis with a 2-week history of intermittent fever and acute onset of lethargy, anorexia, and ataxia. Although the clinical signs were nonspecific, the results of initial hematologic and biochemical analysis were consistent with a chronic inflammatory process. Thoracic radiographs revealed an increased fine reticulonodular interstitial opacity throughout the dorsal caudal lung fields. Cytologic examination of bronchoalveolar lavage (BAL) fluid showed mixed inflammation with many mononuclear phagocytes containing single, spherical, intracytoplasmic fungal organisms. Four mold species were cultured in low numbers from the BAL fluid. One of the fungal elements observed on the culture plates was identified as Acremonium strictum by real-time polymerase chain reaction (PCR). A diagnosis of fungal pneumonia due to A strictum was made based on the results of thoracic imaging, cytologic evaluation, culture, and PCR testing. The horse made an uneventful recovery with supportive treatment and was disease-free based on normal physical, radiographic, and cytologic findings at 21 days after presentation. To our knowledge, this is the first report of isolation of A strictum from the BAL fluid of a horse with interstitial pneumonia.     

Evaluation of Abdominal Fluid: Peripheral Blood Creatinine and Potassium Ratios for Diagnosis of Uroperitoneum in Dogs

Objective: To determine the clinical efficacy of abdominal fluid to peripheral blood ratios of creatinine and potassium concentrations to diagnose uroperitoneum in dogs.
Design: Records of 13 dogs with confirmed uroabdomen were retrospectively analyzed. Prospective evaluation of 8 dogs with nonrenal ascites provided data for a control population.
Setting: Veterinary Medical Teaching Hospital.
Animals: Client owned dogs.
Interventions: None
Measurements and Main Results: Abdominal fluid potassium (mEq/L) and creatinine concentrations (mg/dl) were recorded. Peripheral blood potassium and creatinine concentrations were also recorded. Ratios were calculated based on these values. An abdominal fluid creatinine concentration to peripheral blood creatinine concentration ratio of > 2:1 was predictive of uroabdomen in dogs (specificity 100%, sensitivity 86%). An abdominal fluid potassium concentration to peripheral blood potassium concentration of > 1.4:1 is also predictive of uroabdomen in dogs (specificity 100%, sensitivity 100%). All dogs with uroabdomen had an abdominal fluid creatinine concentration that was at least 4 times normal peripheral blood levels.
Conclusion: Abdominal fluid to peripheral blood potassium and creatinine ratios provide a means to diagnose uroperitoneum in dogs without elevated peripheral blood creatinine.     

PCR examination of bronchoalveolar lavage samples is a useful tool in pre-clinical diagnosis of ovine pulmonary adenocarcinoma (Jaagsiekte)

Ovine pulmonary adenocarcinoma (OPA) is a contagious lung tumour of sheep caused by Jaagsiekte sheep retrovirus (JSRV). The disease is a particular problem in flocks in many parts of the world. The aim of the study was to assess screening methods for individual animals as a prelude to future eradication trials. Results of histological examination were used as the standard to evaluate the relative sensitivity and specificity of an established heminested polymerase chain reaction (PCR) test for JSRV proviral DNA from blood and bronchoalveolar lavage (BAL) samples. PCR results from tissue samples are included as control data. PCR testing of blood samples was found to have an estimated sensitivity of only 10% (95% confidence interval (CI) 3-20) while the sensitivity of the PCR test on BAL samples was 89% (CI 79-96) in comparison to the results of histological examination. We conclude that PCR testing of BAL samples is an effective confirmatory test for sheep with suspected clinical OPA. It is also a useful tool for the pre-clinical identification of individual infected sheep within an infected flock and therefore may prove beneficial in future control or eradication programmes.     

Eosinophilic bronchopneumopathy in dogs

Eosinophilic bronchopneumopathy was diagnosed in 23 young dogs. Clinical signs included cough, gagging, and retching in all dogs, dyspnea in 21 dogs (91%), and nasal discharge in 12 dogs (52%). The most common radiographic findings were a moderate to severe bronchointerstitial pattern (68%, 13 of 19 dogs). Bronchoscopic findings included the presence of abundant yellow-green mucus or mucopurulent material (70%, 16 of 23 dogs) and severe mucosal thickening with an irregular or polypoid appearance (52%, 12 of 23 dogs), with partial airway closure during expiration in 3 dogs (13%). Peripheral blood eosinophilia was noted in 14 of 23 dogs (61%). Inflammatory cells in brush or bronchoalveolar lavage fluid cytologic preparations comprised more than 50% eosinophils in 14 of 23 dogs (61%), and 20-50% eosinophils in 6 dogs (26%). Eosinophilic infiltration of the bronchial mucosa was observed in biopsies from 19 dogs and was graded as mild (37%, 7 dogs), moderate (32%, 6 dogs), or severe (32%, 6 dogs). The mean serum immunoglobulin A concentration was almost double that of a population of 20 healthy dogs of various breeds. Oral glucocorticoids were administered on alternate days with progressive tapering of the dose; the dosage at maintenance varied between 0.1 and 1.0 mg/kg every other day. No relationship was found between the duration of clinical signs and the maintenance dosage or the cytologic and histopathologic grades.     

Detection and identification of Toxocara canis DNA in bronchoalveolar lavage of infected mice using a novel real-time PCR

Toxocarosis is a zoonosis with worldwide distribution caused by Toxocara spp. of dogs and cats. In humans, diagnosis relies mainly on detection of parasite-specific antibodies. Although serological assays in current use have defined sensitivity and specificity, the problem of cross-reactivity still remains, particularly in areas of endemic polyparasitism. Microscopic detection of the parasite in tissue biopsies is not recommended for diagnosis because larvae can be difficult to locate, and finding the parasite eggs in faeces is not applicable since the larvae do not develop to the adult stage in the human host. In this study we describe a novel real-time PCR (‘Nemo-PCR’) that, in combination with DNA sequencing, allows the detection and identification of Toxocara canis and other nematodes in the Superfamily Ascaridoidea. Results indicate that this approach can detect Toxocara spp. DNA in bronchoalveolar lavage (BAL) of experimentally-infected mice. For diagnostic purposes further studies are necessary to evaluate this assay including testing human BAL fluid. The availability of such a direct assay would improve diagnosis of toxocarosis particularly for patients with pulmonary signs and symptoms.