The pathology of spontaneous paratuberculosis in the North American bison (Bison bison)

Gross and histopathologic examinations were performed on 70 North American bison (Bison bison) from a Mycobacterium avium paratuberculosis culture-positive herd. The bison examined were part of a breeding herd totaling 2,800 animals. Eight of 70 (11%) animals had gross findings of intestinal mucosal thickening, and 16 of 70 (23%) of the animals had enlarged mesenteric lymph nodes. Histologic lesions compatible with Johne's disease were diagnosed in 30 of 70 (43%) bison on the basis of the demonstration of noncaseating granulomatous inflammatory infiltrates and of one or more acid-fast bacilli characteristic of Mycobacterium avium paratuberculosis. A suspicious diagnosis of Johne's disease was obtained in 11 of 70 (16%) bison on the basis of the observation of noncaseating granulomatous inflammatory infiltrates without demonstrable acid-fast bacteria. Twenty-nine of 70 (41%) animals were assessed as histologically paratuberculosis free. Histologic results were compared to Johne's disease tests such as culture, serology, and polymerase chain reaction, which were performed on some of the cohort animals.     

Treatment of diplomonad intestinal parasites with magnesium sulphate at a commercial rainbow trout (Oncorhynchus mykiss) facility

Rainbow trout (average weight of 2 g) in fresh water experienced high mortality and were infected with a diplomonad intestinal parasite. Tanks of fish experienced an immediate reduction in mortality after an in-feed treatment with 3% Epsom salts for 2 d. Treatments had to be applied several times, but in each case there was a similar reduction in mortality.     

Usefulness of the murine model to study the immune response against Histoplasma capsulatum infection

The present paper is an overview of the primary events that are associated with the histoplasmosis immune response in the murine model. Valuable data that have been recorded in the scientific literature have contributed to an improved understanding of the clinical course of this systemic mycosis, which is caused by the dimorphic fungus Histoplasma capsulatum. Data must be analyzed carefully, given that misinterpretation could be generated because most of the available information is based on experimental host–parasite interactions that used inappropriate proceedings, i.e., the non-natural route of infection with the parasitic and virulent fungal yeast-phase, which is not the usual infective phase of the etiological agent of this mycosis.     

Penicillin therapy of spontaneous streptococcal meningitis in pigs

Oral prophylactic medication with either procaine penicillin G or a mixture of chlortetracycline, sulphadimidine and procaine penicillin G reduced the incidence of streptococcal meningitis in a herd of pigs with a high recorded prevalence of the disease, but to a significant extent (P less than 0.01) only in those pigs receiving procaine penicillin G. Subsequent studies showed that after oral administration of procaine penicillin G, benzylpenicillin was detectable in plasma only at very low concentration and similar results were obtained using the potassium salt of penicillin G. However, phenoxymethyl penicillin administered orally provided high plasma concentrations of this drug. A further investigation demonstrated that despite the low plasma concentrations of penicillin after oral administration of the procaine salt, gastrointestinal and urinary concentrations of the drug were relatively high for up to five hours.     

Morphine, pethidine and buprenorphine disposition in the cat

Pharmacokinetics of morphine, buprenorphine and pethidine were determined in 10 cats. Six cats received morphine (0.2 mg/kg) intravenously and four intramuscularly. Five received buprenorphine (0.01 mg/kg) intravenously and six intramuscularly. Six received pethidine (5 mg/kg) intramuscularly. Jugular venous blood samples were collected at time points to 24 h, and plasma morphine concentrations were measured by high performance liquid chromatograpy (HPLC), buprenorphine by radioimmunoassay (RIA) and pethidine by gas chromatography. Our data for morphine show elimination half-life (t1/2el) 76.3 min intravenous (i.v.) and 93.6 min intramuscular (i.m.); mean residence time (MRT) 105.0 and 120.5 min; clearance (Clp) 24.1 and 13.9 mL/kg/min; and volume of distribution (V(dss)) 2.6 and 1.7 L/kg, respectively. Comparable data for buprenorphine are t1/2el 416.8 and 380.2 min; MRT 417.6 and 409.8 min; Clp 16.7 and 23.7 mL/kg/min; and V(dss) 7.1 and 8.9 L/kg. For i.m. pethidine, t1/2el 216.4 min; MRT 307.5 min; Clp 20.8 mL/kg/min and V(dss) 5.2 L/kg. For i.m. dosing, the tmax for morphine, buprenorphine and pethidine were 15, 3 and 10 min, respectively. The pharmacokinetics of the three opioids in cats are broadly comparable with those of the dog, although there is a suggestion that the cat may clear morphine more slowly.     

Measurement of serum immunoglobulin concentration in killer whales and sea otters by radial immunodiffusion

Killer whales and sea otters maintained in captivity are the subjects of routine health monitoring programs, and interest in immunologic studies in sea otters has been rising recently in response to potential impacts from infectious disease and environmental pollution on the threatened southern sea otter population. Development of species-specific reagents for immunologic studies in these two marine mammals is currently in its infancy. In this study, killer whale and sea otter immunoglobulin-specific polyclonal antibodies were generated, and used to develop tests for serum Ig concentration in the killer whale (Orcinus orca) and the southern (Enhydra lutris nereis) and northern sea otter (Enhydra lutris lutris). Killer whale serum IgG was purified using caprylic acid/ammonium sulfate precipitation. Sea otter plasma IgG was purified using protein-A-agarose. Polyclonal anti-Ig antisera were produced in rabbits, and specificity confirmed by immunoelectrophoresis. Radial immunodiffusion was used to measure Ig concentration in serum or plasma samples derived from 21 captive killer whales, 18 wild and 4 captive southern sea otters and 15 wild and 4 captive northern sea otters grouped by age. Mean killer whale serum Ig concentration (+/-95% confidence interval) ranged from 15.04 +/- 3.97 g/l for animals aged 0-5 years to 26.65 +/- 9.8 g/l for animals aged >10 years. Mean sea otter serum Ig concentration (+/-95% confidence interval) ranged from 28.39 +/- 11.00 g/l for southern sub-adults to 32.76 +/- 11.58 g/l for southern adults. No significant difference in serum Ig concentration was found between southern and northern sea otters. Serum Ig concentrations in two northern sea otter pups were low compared to those of adult sea otters. The two serum Ig quantitation assays produced were highly specific and reproducible and will be useful additions to the limited number of tests available for immune function in these marine mammal species.     

A biomechanical comparison of headless tapered variable pitch compression and ao cortical bone screws for fixation of a simulated midbody transverse fracture of the proximal sesamoid bone in horses

OBJECTIVE: To compare mechanical properties and failure characteristics of 2 methods of fixation for repair of a transverse, midbody fracture of the proximal sesamoid bone (PSB): 4.5-mm AO cortical bone screw (AO) placed in lag fashion and 4/5-mm Acutrak (AT) self-compressing screw. STUDY DESIGN: An in vitro biomechanical evaluation of intact forelimb preparations and forelimb preparations with a simulated midbody PSB fracture stabilized by a bone screw. SAMPLE POPULATION: Sixteen paired and 8 unilateral cadaveric equine forelimbs. METHODS: A midbody transverse osteotomy was created in the medial PSB of bilateral forelimbs of 8 equine cadavers. The osteotomized PSB in 1 forelimb from each cadaver was repaired with an AO screw. The osteotomized PSB in each contralateral limb was repaired with an AT screw. Eight unilateral intact control limbs were also studied. Mechanical properties were determined from axial compression, single cycle to failure, load-deformation curves. Failure characteristics were determined by evaluation of video images and radiographs. RESULTS: No statistically significant differences were found between repair groups. Both AO and AT groups had significantly lower mechanical properties than intact limbs except for stiffness. CONCLUSION: AO and AT constructs were mechanically comparable when used to stabilize a simulated midbody fracture of the medial PSB. Both constructs were mechanically inferior to intact limbs. Clinical Relevance- The AT screw should be considered for clinical use because of the potential for less soft tissue impingement and superior biocompatibility compared with the stainless-steel AO screw. However, postoperative external coaptation is necessary to augment initial fracture stability for either fixation method, and to maintain a standing metacarpophalangeal joint dorsiflexion angle between 150 degrees and 155 degrees.     

Retrospective study of the relationships between age, inflammation and the isolation of bacteria from the lower respiratory tract of thoroughbred horses

A total of 1235 tracheal aspirates taken from 724 thoroughbreds in race training, aged from two to 10 years, were examined cytologically and bacteriologically. An inflammation scoring system on a scale of 0 to 9 was devised to allow the severity of lower airway disease to be assessed from the cytological results. The inflammation scores were closely related to the isolation of bacteria (P<0.001), and the most common bacterial isolates were Streptococcus zooepidemicus, Streptococcus pneumoniae and Pasteurella/Actinobacillus-like species. Lower airway disease was less common in older horses (P = 0.031), and the groups at highest risk were the two- and four-year-olds. Lower airway inflammation was more common in the four-year-olds at National Hunt yards than in the four-year-olds at flat racing yards (P = 0.040, odds ratio = 3.80).