Antibiotic aerosolization: the effect on experimentally induced Alcaligenes rhinotracheitis in turkeys

Oxytetracycline hydrochloride was delivered by aerosol twice daily for 3 days to uninfected turkeys and to turkeys experimentally inoculated with Alcaligenes faecalis. The clinical, microbiological, and histological changes in the upper respiratory tracts were studied. No lesions were observed in the tracheas of uninoculated poults exposed to the aerosol. In experimentally infected poults, clinical signs included ocular and nasal discharges and open-mouthed breathing. Histologic lesions included progressive bacterial colonization of ciliated epithelium, loss of cilia, depletion of mucin from goblet cells, and accumulation of inflammatory cells within the tracheal lumen. Aerosolization of oxytetracycline effected a temporary decrease in bacterial colonization and a delay in clinical signs and histologic lesions in infected treated poults compared with untreated infected poults. Bacterial colonization and histologic lesions in the tracheas of both treated and untreated infected poults were similar by 4 days after the treatment was discontinued. This study indicates additional research with bactericidal antibiotics is needed to further evaluate antibiotic aerosolization as a treatment for alcaligenes rhinotracheitis.     

Antibiotic aerosolization: tissue and plasma oxytetracycline concentrations in turkey poults

Oxytetracycline hydrochloride (OTC) was delivered by aerosol to healthy 3-week-old turkeys. Trachea, lung, and plasma were evaluated for OTC levels at 1, 4, 8, 12, 24, and 48 hours after aerosol exposure. In Expt. 1, 15 poults in a modified Horsfall unit were exposed to 1 g OTC/m3 of air using a DeVilbiss ultrasonic nebulizer. In Expt. 2, 25,000 poults in a commercial confinement unit were exposed to 0.075 g of OTC/m3 of air using a Fogmaster fogger. In each case, initially high tracheal and lung OTC concentrations were obtained. OTC levels in the trachea fell to less than 1 microgram/g between 4 and 8 hours postexposure. Plasma OTC levels remained low throughout both experiments. Oxytetracycline was still detectable in room air 60 min after aerosol exposure and before ventilation was restored. This method of administration may have promise for use in respiratory infections, but additional studies are needed to further define the use of aerosol therapy in poultry production units.     

Lightning injury in an outdoor swine herd.

Three pigs, weighing 63 kg-70 kg each, from a group of 8 pigs in an outdoor pen that was struck by lightning were necropsied. All 3 pigs presented with hind limb paralysis. The only lesions identified were multiple fractures of the last (seventh) lumbar vertebral body and first sacral vertebral segment, with dorsal displacement of the sacrum and transection of the distal spinal cord and spinal nerves. Hemorrhages extended from the fracture sites into muscles immediately surrounding the lumbosacral junction and retroperitoneally into the pelvic cavity. These hemorrhages were not clearly visible until the pelvic region was dissected. Lesions commonly found in human lightning-strike victims were not present in these pigs. Because vertebral fractures may be the only lesions and may be grossly subtle in heavily muscled pigs, careful pelvic and vertebral dissection is recommended in cases of suspected lightning strike and electrocution.     

Effects of Bordetella avium infection on the pulmonary clearance of Escherichia coli in turkeys

Thirty-six 1-day-old turkeys were inoculated intranasally with Bordetella avium (BA) strain 838. Noninoculated hatchmates (n = 36) were housed separately. At 2 and 4 weeks of age, 15 inoculated (BA+) and 15 noninoculated (BA-) turkeys were exposed to an aerosol of virulent Escherichia coli. The remaining six BA+ turkeys and six BA- turkeys were used as controls (ie, not exposed to E coli). Turkeys were necropsied on postaerosolization days 0 (immediately after aerosolization), 1, 3, 5, and 7. Lung and tracheal specimens were collected from each turkey for bacterial quantitation and histologic examination. A 1-ml blood sample was collected for detection of bacteremia. Numbers of E coli in lung specimens from 2- and 4-week-old turkeys were not significantly different between BA+ and BA- groups (pooled data over time); however, numbers of E coli isolated from tracheal specimens were significantly greater in BA+ turkeys than those in BA- turkeys. Although the incidence of pulmonary abcesses and E coli bacteremia was greater in 2-week-old turkeys than in 4-week-old turkeys, the incidence was not different between BA+ and BA- turkeys. At both ages, air sacculitis developed more often and was more severe in BA+ turkeys than in BA- turkeys. Hyperplastic bronchus-associated lymphoid tissue was found more often in BA+ turkeys than in BA- turkeys and appeared to be the first site of heterophil infiltration after E coli aerosolization.     

The cytologic and histologic diagnosis of ureteral fibroepithelial polyp in a dog

A 6-year-old, intact male, brindled, 30-Lb English Bulldog presented to the Purdue University Veterinary Teaching Hospital with a recurrent history of hematuria, periuria, and lethargy that responded temporarily to antibiotic therapy. The work-up included a complete blood count, serum biochemical profile, complete urinalysis, diagnostic imaging (abdominal radiographs and ultrasound with contrast urography), and exploratory laparotomy. The diagnostic imaging findings and subsequent exploratory revealed a unilateral, intraluminal, right-sided, 3-cm ureteral mass extending from the proximal ureter into the renal pelvis. Subsequently, a unilateral right-sided ureteronephrectomy followed by biopsy with cytopathology/cytology (impression smears) and histopathology of the ureteral mass was performed. The cytopathologic interpretation was benign mesenchymal proliferation with mildly atypical urothelial cells. The association of this mass with vascular tissue and a benign nuclear appearance on cytology is similar to reports of fibroepithelial polyps (FEPs) and myxomatous tumors. Histopathology diagnosed the mass as an FEP. Cytopathology proved useful in the presumptive diagnosis of this benign urothelial polyp. To the authors' knowledge, this is the first report using cytopathology to depict and characterize FEPs in veterinary and human medical literature.     

Cholangiectasis and duodenal diverticulosis in a farm-raised elk (Cervus elaphus)

A 6-year-old male elk presented in August with a 4-month history of weight loss and a 1-day history of being recumbent and unable to rise. The elk's body condition score was 1.5/5. Hematology and blood chemistry showed an inflammatory leukogram, mild electrolyte abnormalities, and elevated liver enzyme activities. Because of poor prognosis, the owner elected euthanasia. On necropsy, 8 diverticula were in the duodenum distal to the common bile duct, which was dilated and filled with feed material. Many intrahepatic bile ducts were dilated up to 5 cm, were filled with ingesta and gritty material, and had walls thickened up to 1.5 mm. On histologic examination, mural thickening of dilated bile ducts was because of increased fibrous connective tissue with inflammatory cell infiltration and hyperplastic and hypertrophic epithelial lining. Portal tracts diffusely contained hyperplastic bile ducts and had increased amounts of fibrous connective tissue. Abscesses that contained bacteria were scattered throughout the liver. Duodenal diverticula lacked the tunica muscularis, and the muscularis mucosa was hypertrophied. Caudal to some diverticula, the duodenal lumen was narrowed. An additional finding was embolic pneumonia with fungi morphologically and immunohistochemically consistent with Aspergillus spp.     

Vitamin E supplementation does not mitigate the acute morbidity effects of porcine reproductive and respiratory syndrome virus in nursery pigs

The objective of this study was to determine whether feeding a vitamin E-rich diet would benefit nursery pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV). Sixty-four pigs were subjected to one of four treatment combinations (2 x 2 factorial) of dietary vitamin E (adequate or excess) and PRRSV (medium or inoculation with VR-2385 isolate P-129). Pigs were fed experimental diets during a 3-wk period before inoculation as well as during a 12-d period after inoculation. Growth performance was determined throughout the study, and lipid peroxidation in liver, glutathione peroxidase (GPX) activity in serum, circulating white blood cells, and serum interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) were determined in samples collected from pigs killed 4 or 12 d after inoculation. Infection by PRRSV (P < 0.001) induced a marked decrease in both ADFI and ADG, but neither the main effect of diet nor the diet x PRRSV interaction was significant. Neither diet nor PRRSV affected feed efficiency. At 12 d after inoculation, lipid peroxidation in liver and GPX activity in serum were lower in pigs fed excess vitamin E than in those fed adequate vitamin E (P < 0.01), suggesting that the diet high in vitamin E bolstered the antioxidant status of the pigs. However, PRRSV did not affect lipid peroxidation in liver or serum GPX activity, and the diet x PRRSV interaction was not significant. White blood cell counts were decreased and IFN-gamma, and IL-1beta were increased (P < 0.05) 4 and 12 d after inoculation in PRRSV-infected pigs, but neither diet nor the diet x PRRSV interaction was significant. Collectively, these results indicate that increasing antioxidant defenses by feeding high levels of vitamin E did not ameliorate the effects of PRRSV on decreased growth, leukopenia, and increased serum IL-1beta and IFN-gamma. Thus, feeding nursery pigs a diet high in vitamin E may not be useful for mitigating the acute morbidity effects of PRRSV infection.