The epizootiology of tuberculosis of cattle in the Federal Republic of Germany

Mycobacterial strains from different outbreaks of tuberculosis of cattle in Germany from 1996 to 2001 were differentiated by two molecular biological methods (Spoligotyping, RFLP IS6110). The causative agent was in one case Mycobacterium (M.) africanum, in 10 cases M. bovis and in 17 cases M. bovis ssp. caprae, respectively. The results of the molecular biological methods are discussed from the perspective of epizootiology and the particular importance of infections by M. bovis ssp. caprae emphasized. Direct contact of the animals, purchase from infected stocks, infected zoo animals and wildlife, as well as livestock handlers are discussed as possible sources of infection.     

Molecular characterization of Listeria monocytogenes and the significance for food hygiene

Research on the pathogen Listeria monocytogenes is a key issue both for the clinical and the food microbiologist owing to the unique pathway of infection and the exposure of humans via contaminated foods. Although, in Austria, the incidence of listeriosis is about 870-fold lower than the incidence for Salmonella infection, the food law manages both foodborne pathogens with a comparable stringency. The current risk management is based on the assumption that environmental L. monocytogenes isolates, from which the pool of "foodborne" isolates is recruited, are of similar pathogenicity compared to clinical and outbreak isolates. This verdict became doubted in the recent years. Characterization of L. monocytogenes by virulence gene sequencing, virulence studies in vivo and in vitro and by molecular typing was considerably stimulating the discussion on virulence variability in L. monocytogenes. This article provides insights in the value of epidemiological follow-up studies by presenting a typing study on 15 cases of listeriosis observed in a district hospital in Turkey. Furthermore results from typing L. monocytogenes either by virulence gene sequencing, mismatch amplification mutation assay or by pulsed field gel electrophoresis are discussed. The close interaction of molecular microbiology with food microbiology both in applied and basic science is currently creating a new discipline of molecular food microbiology. We are convinced that veterinary medicine will contribute to this exiting development in a fruitful way.     

Immunogenicity of bovine parainfluenza type 3 virus proteins encapsulated in nanoparticle vaccines,following intranasal administration to mice

Stimulation of long lasting, protective immunity to respiratory viruses is often difficult to achieve with conventional respiratory vaccines. Polymeric nanoparticles, incorporating viral proteins have been shown to offer sustained release of antigen, with consequent prolongued stimulation of the respiratory immune system. In this paper the efficacy of two nanoparticle vaccines (poly-lactide-co-glycolide, PLGA; polymethylmethacrylate, PMMA), incorporating proteins of bovine parainfluenza type 3 virus (BPI-3) was investigated. As a preliminary to experiments in calves, it was considered essential to demonstrate immunogenicity of the experimental vaccine in mice. Mice immunised with PLGA nanoparticles, containing BPI-3 proteins, developed higher levels of virus-specific antibody than mice immunised with the PMMA vaccine or with soluble viral proteins alone. Immunoblotting using serum from the vaccinated mice, demonstrated strong reactions against the major BPI-3 proteins.     

Conservative management of 17 horses with nonarticular fractures of the tibial tuberosity

REASONS FOR PERFORMING STUDY: Fractures of the tibial tuberosity (FTT) are caused by direct trauma, and are the second most commonly reported injury in event horses with stifle trauma. Conservative management of horses with FTT has been advocated, but results and prognosis for this method of therapy are unknown. OBJECTIVES: To report and review the findings of a retrospective study of 17 horses admitted to a veterinary teaching hospital from 1986-2001 with nonarticular FTT that received conservative management. METHODS: Subject details, aetiology of the accident, limb affected, degree of lameness at time of admission, size and degree of displacement of the fracture fragment, complications such as comminution of the fracture fragment or damage to soft tissue structures within the affected stifle, and treatment recommendations were obtained from medical records. Owners and trainers were contacted regarding the horse's return to athletic use. The follow-up period consisted of 11-154 months. RESULTS: Two horses were reportedly sound, but unable to return to competition for unrelated reasons. Of the horses that completed the rehabilitation period, 12/15 (80%) returned to athletic use at the same level as before the injury. Three horses were diagnosed with damage to soft tissue supporting structures of the affected stifle and could not return to their former level of competition. CONCLUSIONS: Concurrent soft tissue damage, diagnosed at the time of the initial injury, was statistically significant in precluding horses from returning to athletic careers. All other variables were found to have no effect upon outcome. POTENTIAL CLINICAL RELEVANCE: This retrospective study suggests that the conservative management of nonarticular FTT is a viable treatment modality in managing athletic equine patients presenting with these fractures.     

Immunohistochemical characterisation of the lesions of canine idiopathic pericarditis

Pericardial tissue was obtained from 14 dogs with idiopathic pericarditis, and from three dogs with pericardial effusion associated with neoplastic disease, for histopathological assessment and characterisation of infiltrating leucocytes by immunohistochemistry. The major pathological change was extensive pericardial fibrosis which was generally accompanied by a mixed inflammatory response that was of greatest intensity at the cardiac surface of the tissue. Perivascular lymphoplasmacytic aggregates were present at the pleural surface and within the fibrosed pericardium. There were no features that clearly distinguished the samples from dogs with neoplastic disease from dogs with idiopathic pericarditis. The pericardial infiltrates were dominated by MAC 387+ monocyte-macrophages and plasma cells expressing immunoglobulin (Ig)A or IgG. CD3+ T lymphocytes and major histocompatibility complex (MHC) class II+ macrophages were less common, although the perivascular aggregates were mixtures of T and B lymphocytes and a proportion of fibroblasts expressed MHC class II. There was no vascular pathology or deposition of immunoglobulin or complement within vessel walls. These findings are consistent with an immune response dominated by humoral effector mechanisms (Th2 immunity) but do not clearly support a primary immune-mediated pathogenesis for idiopathic pericarditis.     

Cloning,expression, purification,and biological activity of five feline type I interferons

Type I interferons (IFN) are important mediators of the host defense against viral infections in mammals. In humans multiple subtypes of IFN-alpha exist, most of which possess antiviral activity. Little is known about the type I IFN genes in cats and the role they may play in feline immunological responses to viruses. We have isolated cDNAs encoding five feline IFN-alpha (feIFN) subtypes that share from 95 to 99% amino acid sequence identity. FeIFN-alpha5 has five additional amino acids inserted at position 139, which are not present in the other four subtypes. Sequence identity of the feIFN proteins encoded by the five clones compared to human IFN-alpha2 is approximately 60%. Unlike most of the human subtypes, each of the five feline IFN sequences has an N-glycosylation recognition site. Expression of all five feIFN-alpha subtypes in Chinese hamster ovary (CHO) cells was confirmed by Western blot analysis, and all resulting proteins were glycosylated. The antiviral activity of each feIFN-alpha subtype produced in transiently transfected CHO cell cultures was tested in vitro. In addition, subtype feIFN-alpha6 was expressed in the yeast, Pichia pastoris. The resulting secreted mature recombinant protein was purified and demonstrated significant antiviral activity and induction of 2',5'-oligoadenylate synthetase activity in vitro.     

Matrix metalloproteinase activity in tumor, stromal tissue, and serum from cats with malignancies

Matrix metalloproteinases (MMPs) are enzymes that play key roles in angiogenesis, tumor invasion, and metastasis in a wide variety of species. The purpose of this study was to evaluate pro and active MMP 2 and 9 concentrations in tumor, normal stromal tissue, and serum from tumor-bearing cats. We hypothesized that serum concentrations of pro and active forms of MMPs 2 and 9 would be predictive of MMP concentrations in tumor tissue and that these MMP concentrations would correlate with the histopathologic grade of the malignancies. Pro and active forms of MMPs 2 and 9 were determined by gelatin zymography and subsequent computerized densitometry from tumor and nearby stromal tissue and serum from 49 cats with various malignancies. The serum concentrations of MMPs from these tumor-bearing cats were compared with serum concentrations of MMPs from 44 normal cats of similar age and gender. Measurable concentrations of MMPs 2 and 9 were found within tumor, stromal, and serum samples. Mean concentrations of total pro and active MMPs 2 and 9 within tumor tissue were significantly higher (P values <.0001, .0031, <.001, and .0064, respectively) when compared with stromal tissue from the same animals. Serum MMP concentrations from tumor-bearing cats were higher than those from normal cats. Poor correlation was found between serum MMP concentrations and tissue MMP concentrations of increasing histologic grades of malignancies.     

Effects of dietary flaxseed oil supplementation on equine plasma fatty acid concentrations and whole blood platelet aggregation

An 18-week feeding trial was performed to investigate the effects of an omega-3 (n-3) fatty acid-enriched ration on plasma fatty acid concentrations and platelet aggregation in healthy horses. Flaxseed oil served as the source of the n-3 fatty acid alpha-linolenic acid (ALA). Twelve horses were fed dietary maintenance requirements using a complete pelleted ration (80%) and timothy grass hay (20%) for a 2-week acclimation period before being randomly assigned either to a treatment (group 1) or control (group 2) group. Group 2 horses (n = 6) were fed the diet described in the acclimation period, whereas group I horses (n = 6) were fed a 10% flaxseed oil-enriched complete pellet (80%) and grass hay (20%). Biological samples and physical measurements were collected at one point during the acclimation period (week 0) and every 4 weeks thereafter (weeks 4, 8, 12, and 16). Body weight, CBC (including platelet count), plasma fibrinogen. electrolyte (Na, K, and Cl) concentrations, and biochemical profile enzyme activities (aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, and creatine kinase) did not change markedly with diet. Platelet aggregation was not altered by the supplementation of flaxseed oil in these healthy horses, although increases in plasma cis-polyunsaturated 18-carbon fatty acids C18:3; n-3 (ALA) and C18:2; n-6 (linoleic acid), biologically active C20:5; n-3 (eicosapentaenoic acid [EPA]), and malondialdehyde (MDA) were evident. There were no marked decreases in C20:4; n-6 (arachidonic acid [AA]) or increases in C22:6; n-3 (docosahexaenoic acid [DHA]), signifying that flaxseed oil may have had a high percentage of omega-6 (n-6) fatty acids as well as n-3 fatty acids, and this relatively high n-6: n-3 fatty acid ratio may have affected the biochemical effect of n-3 fatty acids. In healthy horses supplemented with flaxseed oil, platelet aggregation was not altered, which may have been due to the limited biologic effect in healthy subjects or the inability of flaxseed oil to induce the necessary biochemical effect of replacing n-6 fatty acids with n-3 types.     

Specificity of inhibition between Salmonella strains

A phenomenon of inhibition among Salmonella organisms colonizing the gut of young animals can be demonstrated which is important in connection with immunization using live Salmonella vaccines. For practical utilization of this inhibition phenomenon, research into its specificity is very important. In vitro broth culture and animal experiments have shown inhibition to be genus-specific, i.e. there is no inhibition between strains of different genera of Enterobacteriaceae in most cases. The strongest inhibition occurs between isogenic (identical genotype) strains (strain-specific inhibition). This applies to Salmonella and other genera of Enterobacteriaceae. There was a close correlation between the degree of the inhibitory effect and the genetic relatedness of the strains, as has been demonstrated in Salmonella strains of different epidemiological classification. The inhibitory capacity was most pronounced among closely related strains. Clonal strains of Salmonella Enteritidis phage type 4 fully inhibited caecal colonization by Salmonella Enteritidis phage type 4 strains in 65% of the combinations tested in chicks. In broth culture experiments, the share of combinations with complete inhibition was above 90%. A significant inhibitory competence of a selected strongly inhibitory Salmonella Enteritidis phage type 4 strain against the majority of Salmonella Enteritidis field isolates can be expected. However, Salmonella Enteritidis strains of all phase types showed almost no inhibitory competence against other Salmonella serotypes.