Experimental infection of weaned piglets with Campylobacter coli – Excretion and translocation in a pig colonisation trial

Campylobacter (C.) is one of the most common food-borne pathogen causing bacterial enteric infections in humans. Consumption of meat and meat products that have been contaminated with Campylobacter are the major source of infection. Pigs are a natural reservoir of Campylobacter spp. with C. coli as the dominant species. Even though some studies focussed on transmission of C. coli in pig herds and the excretion in faeces, little is known about the colonisation and excretion dynamics of C. coli in a complex gut microbiota present in weaned piglets and the translocation to different tissues.     

Comparative immunopathogenesis of mild,intermediate, and virulent strains of classic infectious bursal disease virus

Differences in the immunopathogenesis of several strains of infectious bursal disease virus (IBDV) were compared. The strains included a virulent virus (IBDV-IM) and three vaccine viruses that included an intermediate vaccine virus (IBDV-B2) and two mild vaccine viruses (IBDV-Lukert and IBDV-BVM). The most significant differences were found in the systemic effects of these strains. In comparison with other strains, IBDV-IM antigen was detectable for up to 8 days postinfection (PI) in lymphoid tissues that included spleen and cecal tonsils, whereas only a few IBDV-B2- and IBDV-Lukert- and no IBDV-BVM-inoculated birds had detectable IBDV antigen in these tissues. IBDV-IM induced systemic circulating nitrite levels in over 86% of the birds at days 2 and 3 PI. IBDV-IM suppressed most vigorously the splenic mitogenic response on days 3-8 PI. Among the three vaccine strains, IBDV-B2 was the most virulent of the three, inducing a significant suppression of the mitogenic response (P < 0.05) and the most vigorous lesions in the bursa of Fabricius with the highest possible lesion score of 4 at 3 days PI (P < 0.05). IBDV-BVM was the mildest strain, not inducing any detectable lesions in lymphoid tissue at the tested time points. Whereas all IBDV-BVM-inoculated and 67% and 33% of the IBDV-Lukert- and IBDV-B2-inoculated birds, respectively, had detectable IBDV antigen in the bursa at 4 days postchallenge, none of the IBDV-IM-inoculated birds was positive for IBDV by immunohistochemistry. IBDV-IM induced the highest enzyme-linked immunosorbent assay (ELISA) antibody levels detected at days 8-29 PI (P < 0.05) and the best protection against challenge virus replication in comparison with IBDV-B2 and IBDV-Lukert. Only one of five IBDV-BVM-inoculated birds developed anti-IBDV ELISA antibodies at 29 days PI, and none of the birds was protected against IBDV challenge. We speculate that better protection with more virulent strains was due to more systemic antigenic stimulation on the basis of higher replication of IBDV in extrabursal lymphoid tissues. Interestingly, IBDV-IM did not differ from IBDV-B2 and IBDV-Lukert in its ability to induce T cell accumulation in the bursa at 8 days PI and local interferon-gamma induction from days 2 to 5 PI. These results suggested that the local T cell events in the bursa alone may not be indicative of a rapid and protective immune response.     

Measurement of the elastic properties of the cancellous bone in the femoral head of the dog

The degenerative wear and pathologic damage of the joints are reasons for total endoprotheses in man as well as in dogs. The main problem is the aseptic loosening of the protheses. By usig the finite-element-method, the total endoprothesis is designed with new features, with the purpose of preventing loosening and being better adapted to load transmission. In order to simulate the femur of the dog for the numerical analysis, a material law is developed. By taking into account the anisotropy and the local density of the cancellous bone in the femoral head, the young's modules are experimentally determined. The measurements are performed by ultrasonic methods on femoral heads of euthanised dogs. The results show planar isotropic cancellous bone.     

Automatic image registration of three-dimensional images of the head of cats and dogs by use of maximization of mutual information

OBJECTIVE: To validate mutual information criterion as a ready-to-use technique for automated alignment (ie, registration) of 3-dimensional (3-D) multimodal image data of the head of cats and dogs. SAMPLE POPULATION: Corresponding 3-D magnetic resonance imaging (MRI) and computed tomography (CT) brain scans of a 6-month-old Doberman Pinscher with a brain cyst; CT images of the head of a European shorthair cat with a meningioma before and immediately, 3, and 6 months after surgical resection; and CT and corresponding stacked anatomic cryosection images of the entire head of a 2-year-old sexually intact female Beagle. PROCEDURE: All images were matched retrospectively by use of an in-house computer program developed on the basis of a mutual information image registration algorithm. Accuracy of the resulting registrations was evaluated by visual inspection. RESULTS: All registrations were judged to be highly accurate. Additional manual corrections were not necessary. CONCLUSIONS AND CLINICAL RELEVANCE: Mutual information registration criterion can by applied to 3-D multimodal head images of cats and dogs for full automatic rigid-body image registration. The combination of such aligned images would considerably facilitate efforts of veterinary clinicians as indicated by its widespread use in brain surgery and radiation therapy of humans.     

Reduced efficacy of hemorrhagic enteritis virus vaccine in turkeys exposed to avian pneumovirus

Avian pneumovirus (APV) is an immunosuppressive respiratory pathogen of turkeys. We examined the effect of APV infection on the vaccine efficacy of hemorrhagic enteritis virus (HEV) vaccines. APV was inoculated in 2-wk-old turkeys. Two or four days later, an attenuated HEV vaccine (HEVp30) or marble spleen disease virus (MSDV) vaccine were administered. Virulent HEV challenge was given 19 days after HEV vaccination. APV exposure compromised the ability of HEVp30 and MSDV to protect turkeys against virulent HEV. The protective index values were as follows: MSDV (100%) versus APV + MSDV (0%) (P < 0.05); HEVp30 (60%) versus APV + HEVp30 (30%) (P < 0.05) (Experiment I) and HEVp30 (56%) versus APV + HEVp30 (20%) (P < 0.05) (Experiment II). These data indicated that APV reduced the efficacy of HEV vaccines in turkeys.     

Gadolinium contrast medium administration does not adversely affect T2*‐weighted gradient recalled echo magnetic resonance imaging of the canine brain at 1.5 Tesla

As gadolinium‐based contrast agents are paramagnetic and have T2 shortening effects, they have the potential to adversely affect gradient recalled echo sequences. The aim of this prospective, cross‐sectional study was to evaluate the effects of gadolinium administration on T2*‐weighted sequence diagnostic quality and signal intensity when imaging the canine brain. A total of 100 dogs underwent brain magnetic resonance imaging (MRI) including pre‐ and postcontrast T2*‐weighted sequences acquired with a delay (Group A) or immediately (Group B) following gadolinium administration. Pre‐ and postcontrast images were subjectively compared. In dogs with intracranial enhancing masses, regions of interest were drawn on corresponding images and signal intensity ratios were calculated. The effect of degree and pattern of contrast enhancement, susceptibility artifacts, and time between contrast injection and T2*‐weighted sequence acquisition on signal intensity ratio was evaluated. Overall 31 dogs had contrast enhancing intracranial masses. Subjectively, there was no difference in image quality of T2*‐weighted sequences obtained before and after contrast medium administration. No significant signal intensity differences of intracranial contrast enhancing masses were found (Group A P = 0.9999; Group B P = 0.9992). Susceptibility artifacts did not differ in appearance, and there was no effect on calculated signal intensity ratio (P = 0.8142). Similarly, there was no effect of degree of enhancement or contrast heterogeneity on signal intensity ratio (P = 0.4413). No correlation was found between signal intensity ratio and the time to acquisition (P = 0.199). Administration of gadolinium‐based MRI contrast agents does not adversely affect T2*‐weighted imaging of the brain in dogs at 1.5 T even in the presence of contrast enhancing lesions.     

Efficacy of a modified live intranasal bovine respiratory syncytial virus vaccine in 3-week-old calves experimentally challenged with BRSV

Two experimental bovine respiratory syncytial virus (BRSV) challenge studies were undertaken to evaluate the efficacy of a single intranasal dose of a bivalent modified live vaccine containing BRSV in 3-week-old calves. In the first study, vaccine efficacy was evaluated in colostrum deprived (maternal antibody negative) calves 5, 10 and 21 days after vaccination. Nasal shedding of BRSV was significantly reduced in vaccinated calves challenged 10 or 21 days after vaccination. Virus excretion titres were also reduced in vaccinates challenged 5 days after vaccination but reduction in duration of shedding and total amount of virus shed were not statistically significant. Clinical disease after challenge in this study was mild. In the second study, vaccine efficacy was assessed in calves with maternal antibodies against BRSV by challenge 66 days post-vaccination. Vaccination significantly reduced nasal shedding after challenge and the severity of clinical disease was also reduced.     

Alfven waves in the solar corona

Alfvén waves, transverse incompressible magnetic oscillations, have been proposed as a possible mechanism to heat the Sun's corona to millions of degrees by transporting convective energy from the photosphere into the diffuse corona. We report the detection of Alfvén waves in intensity, line-of-sight velocity, and linear polarization images of the solar corona taken using the FeXIII 1074.7-nanometer coronal emission line with the Coronal Multi-Channel Polarimeter (CoMP) instrument at the National Solar Observatory, New Mexico. Ubiquitous upward propagating waves were seen, with phase speeds of 1 to 4 megameters per second and trajectories consistent with the direction of the magnetic field inferred from the linear polarization measurements. An estimate of the energy carried by the waves that we spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.