Antibodies to bovine parvovirus acquired by neonatal pigs through ingestion of virus and antibody in the diet

The ability of pigs to respond immunologically to ingestion of bovine parvovirus (BPV) was tested by feeding 4 cesarean-derived, colostrum-deprived (CDCD) pigs a live virus-contaminated, liquid diet for the first 4 weeks of life. Virus-neutralizing (VN) antibodies were detected in the serum of 2 of the 4 pigs when they were 4 weeks old. Antibody titer remained at about the same level for several weeks, then decreased during the remainder of the 29-week interval of testing. The relative reactivity of these sera based on results of indirect immunofluorescence paralleled the corresponding VN titer. Neither of the other 2 pigs exposed to BPV had any appreciable immune response. The potential for passive acquisition of antibody from the diet was tested by feeding 4 other CDCD pigs bovine colostrum containing antibodies to BPV and bovine viral diarrhea virus (BVDV) for the first 2 days of life. All had serum VN antibodies for both viruses when they were tested at 2 days of age. The decay rate of the heterologous, passively acquired antibody was approximately linear; however, antibody half-life was relatively short, about 3.5 days, and titers were no longer detectable when pigs were 4 weeks (BPV) and 6 weeks (BVDV) old. An additional 4 CDCD pigs fed a liquid diet without virus or antibody remained free of any appreciable serum reactivity for either BPV or BVDV. Results supported the hypothesis that antibodies for BPV previously detected in the serum of pigs and people may reflect ingestion of virus-contaminated bovine milk or milk products.     

Slide precipitation: a simple method to type Actinobacillus (Haemophilus) pleuropneumoniae

Soluble thermostable antigens prepared from Actinobacillus pleuropneumoniae, as commonly applied in the ring precipitation test, were used in rapid slide tests. This method was easier to perform than the ring precipitation test and showed the same specificity. This specificity was higher than that obtained in slide agglutination tests using whole bacterial cells.     

A study of the predominant genotypes of bovid herpesvirus 1 found in the U.K

The genotypic classification of 84 U.K. isolates of bovid herpesvirus 1 was determined by the restriction endonuclease technique. Preliminary studies with six enzymes (EcoRI, HindIII, HpaI, BamHI, PstI and BstEII) showed that the principal genotypic variants, including the live vaccine strains used in the U.K., could be identified from the digestion patterns with just two endonucleases: HindIII and HpaI. Isolates from the 1960s were all categorised as genotype 2b. From 1977 onwards, genotype 1 has predominated in mainland Britain, with occasional type 2b isolates. Type 2b viruses were isolated from both respiratory and genital disease cases. There was no evidence of genotypes 2a or 3 in the U.K.     

Five field trials on the efficacy of a bovine respiratory syncytial virus vaccine

Five field trials evaluated whether immunization of beef cattle prior to weaning, at weaning, or immediately upon arrival at the feedlot with a commercial bovine respiratory syncytial virus (BRSV) vaccine would reduce subsequent treatment for respiratory disease.

Bovine respiratory syncytial virus vaccination was associated with a significant (p<0.05) reduction in treatment rate in one of three groups of calves immunized prior to weaning (−12%) and in calves immunized upon arrival at the feedlot (−4%).

There was no significant (p>0.05) effect of the BRSV vaccine on treatment rate in calves immunized at weaning, in calves immunized upon arrival at the Saskatoon bull test station, or in yearlings immunized upon arrival at the feedlot.

Although the trend in these field trials was to a sparing effect of the BRSV vaccine, the small reduction in treatment rate may not justify the cost of the vaccination program.

     

Pharmacokinetics of a porcine insulin zinc suspension in diabetic dogs

Ten dogs with naturally occurring diabetes mellitus were injected with a highly purified porcine insulin zinc suspension at a dose according to their expected requirement. Plasma insulin and glucose concentrations were measured at two-hourly intervals over 24 hours following injection. There were either one or two peaks in plasma insulin concentration: one at about four hours (mean 4.3 21.3 [SD]) and another at about 11 hours (mean 11 pM1-85) after the injection. The second insulin peak was seen in only eight dogs. Persistence of elevated plasma insulin concentrations ranged from 14 to 24 hours (mean 17.4 pM 3.65). These results compare favourably with those published for other intermediate-acting insulin preparations used to treat canine diabetes mellitus and suggest that this preparation has useful properties for the successful management of many canine diabetics.     

Veterinary drug bioequivalence determination

A bioequivalence trial is a statistically based comparison of two formulations to demonstrate with a controlled consumer (patient) risk that two formulated drug products are interchangeable. The basic assumption underlying a bioequivalence trial is that essentially the same plasma time-course leads to essentially the same effect allowing two formulations to be interchanged. Bioequivalence is generally assessed using kinetic end points and in practice, two formulations in which bioavailability parameters (rate and extent) differ by 20% or less, with a 90% degree of confidence, are considered to be bioequivalent. In this review, the design and evaluation of bioequivalence studies are presented with special attention given to scientific issues.     

Allergen-specific IgG antibodies in cats with allergic skin disease

An enzyme-linked immunosorbent assay was developed for quantifying feline serum allergen-specific IgG directed against selected house dust, pollen and flea allergens. The assay was used to compare allergen-specific IgG concentrations in sera from healthy cats, cats with non-dermatologic illness, confirmed allergic cats and undiagnosed pruritic cats. Our results demonstrate that cats with confirmed allergic skin disease have significantly more IgG directed against house dust, flea and ryegrass allergens than other cat groups examined. These results support the theory that cats with allergic skin disease have an underlying T_H2 lymphocyte response that directs production of both allergen-specific IgG and IgE.     

Determination of the Inflammatory Potential of Bioaerosols from a Duck‐Fattening Unit by Using a Limulus Amebocyte Lysate Assay and Human Whole Blood Cytokine Response

Inhalation of bioaerosols from animal houses can induce acute inflammatory reactions in the respiratory tract. Determination of the concentration of airborne endotoxins is widely used to characterize this risk. In this study, the activity of bioaerosol samples from a duck‐fattening unit to induce interleukin‐1β (IL‐1β) in human blood and to react with Limulus Amebocyte Lysate (LAL) was investigated. The activity detected in the whole blood assay correlated well with the endotoxic activity found in the LAL assay (Spearmen's ρ = 0.902). However in all samples, the inflammation‐inducing potential was overestimated by the LAL assay. It is assumed that this overestimation could be, in part, a result of an overestimation of the inflammatory potential of endotoxins originating from Pseudomonadaceae by the LAL assay. Pseudomonadaceae were regularly isolated from the air of the duck‐fattening unit. The results presented here indicate that the whole blood assay can be used besides the LAL assay as an additional method to characterize the inflammation‐inducing potential of bioaerosols.     

Spontaneous and experimental glycoprotein storage disease of goats induced by Ipomoea carnea subsp fistulosa (Convolvulaceae)

Spontaneous and experimental poisoning with the swainsonine-containing and calystegine-containing plant Ipomoea carnea subsp fistulosa is described. Three of 8 goats presenting with emaciation, weakness, symmetrical ataxia, posterior paresis, proprioceptive deficits, abnormal posture, abnormal postural reaction, and muscle hypertonia were necropsied. I fistulosa was suspected to be the cause of the neurologic disease in all cases. An experiment was conducted to confirm the diagnosis using 12 goats and diets containing 3 different concentrations of the plant. All goats fed I fistulosa developed neurological signs that were similar to those observed in the spontaneous intoxication. Muscle atrophy and pallor were the only macroscopic changes observed in spontaneous and in experimental intoxication. Histological lesions of spontaneous and experimental animals were similar. The most prominent lesion was cytoplasmic vacuolation in neurons of the central and the autonomous nervous system, pancreatic acinar cells, hepatocytes, Kupffer cells, follicular epithelial cells of the thyroid gland, and macrophages of the lymphatic tissues. Neuronal necrosis, axonal spheroids formation, and astrogliosis were additionally observed in the brain. Ultrastructurally, the cytoplasmic vacuoles consisted of distended lysosomes surrounded by a single-layered membrane. Nonreduced end-rests or sequence of alpha-Man, alpha-Glc, beta(1-4)-GlcNAc, and NeuNAc on lysosomal membrane were revealed by lectin histochemistry. Samples of plants used in the experimental trial contained swainsonine and calystegine and their intermediary derivate. We conclude that I fistulosa induces a glycoprotein storage disease primarily based on the inhibition of the lysosomal alpha-mannosidase by the alkaloid swainsonine.     

Pharmacokinetic-pharmacodynamic integration of danofloxacin after intravenous, intramuscular and subcutaneous administration to rabbits

The pharmacokinetics of danofloxacin was studied following intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) administration of 6 mg/kg to healthy rabbits. Danofloxacin concentration were determined by high-performance liquid chromatography assay with fluorescence detection. Minimal inhibitory concentrations (MICs) assay of danofloxacin against 30 strains of Staphylococcus aureus from several European countries was performed in order to compute pharmacodynamic surrogate markers. The danofloxacin plasma concentration versus time data after i.v. administration could best be described by a two-compartment open model. The disposition of i.m. and subcutaneously administered danofloxacin was best described by a one-compartment model. The terminal half-life for i.v., i.m. and s.c. routes was 4.88, 6.70 and 8.20 h, respectively. Clearance value after i.v. dosing was 0.76 L/kg.h. After i.m. administration, the absolute bioavailability was mean (+/-SD) 102.34 +/- 5.17% and the Cmax was 1.87 mg/L. After s.c. administration, the absolute bioavailability was mean (+/-SD) 96.44 +/- 5.95% and the Cmax was 1.79 mg/L. Danofloxacin shows a favourable pharmacokinetics profile in rabbits reflected by parameters such as a long half-life and a high bioavailability. However, in consideration of the low AUC/MIC indices obtained, its use by i.m. and s.c. route against the S. aureus strains assayed in this study cannot be recommended given the risk for selection of first mutant subpopulations.