PREVALENCE AND CHARACTERIZATION OF SMALL TYMPANIC BONE SPICULES AND DRUMSTICK‐LIKE HYPEROSTOTIC TYMPANIC BONE SPICULES IN THE MIDDLE EAR CAVITY OF DOGS

Rounded, sessile, hyperattenuating structures detected in computed tomography (CT) studies of canine tympanic bullae have been termed “otoliths.” These have been proposed to represent dystrophic mineralizations or heterotopic bone formations in the middle ear that are potentially related to chronic otitis media. Aims of the current study were to describe the prevalence, macroscopic, and histological features of structures consistent with “otoliths” in the canine tympanic cavity. Tympanic bullae from 50 routinely necropsied dogs and 139 retrospectively retrieved CT scans of canine clinical cases were examined. Small tympanic bone spicules with pointed or clubbed tips essentially arising from the free margin of the septum bullae were bilaterally present in the tympanic cavities of all 50 of the necropsied dogs. In 48% of the dogs, “otolith”‐like CT‐detectable bone spicules carrying drumstick‐like hyperostoses that were 1–6 mm in diameter were also present. In the retrospective survey of bulla CT scans of 139 cases, the prevalence of hyperostotic tympanic bone spicules (HTBS) was 20%. Findings from the current study indicated that the presence of small tympanic bone spicules in adult dogs is most likely due to physiological bone growth in the septum bullae and that HTBS represent osseous proliferations of small tympanic bone spicules. However, the factors inducing formation of hyperostotic spicules from small tympanic bone spicules remain unknown. The high prevalence of HTBS displaying a similar appearance in bulla CT scans in dogs suggests that these spicules should be included in a differential diagnosis list for “otoliths.”     

Production of viral vaccines for veterinary use

This review provides inside information on the production of vaccines for veterinary use. The vaccines against rinderpest as well as foot and mouth disease are considered milestones in the history of veterinary vaccine production. Modern vaccines are based on the scientific progress in virology, cell biology and immunology. While naturally occurring attenuated viruses or viruses obtained after passage in different animal species or cell culture were used as vaccine strains in the early vaccines, nowadays targeted mutagenesis can be applied to generate vaccine virus strains. In principle, the antigen production process is the same for live and inactivated vaccines. The vaccine virus is usually grown in cell culture, either in roller bottles or bioreactors. Most live vaccines are freeze-dried in order to enable storage in the refridgerator for a longer period. To this end, a so-called stabilizer is added to the culture medium. The inactivation of the vaccine virus for the production of killed vaccines is done by physical or chemical treatments that lead to denaturation of the proteins or damage of the nucleic acids. The inactivated antigen may be further purified and mixed with an adjuvant. The quality standards for vaccines are layed down in international regulations and laws. Numerous tests are performed during the different production steps and on the final product in order to warrant the quality of each batch.     

Paratuberculosis in a miniature donkey (Equus asinus f. asinus)

Paratuberculosis is mainly an infectious disease of ruminants with worldwide distribution. Infection occurs in early stages of life. Other animal species beyond ruminants are rarely affected, however, experimental and natural infections are possible. A case of paratuberculosis in a miniature donkey (Equus asinus f. asinus) with typical clinical and pathomorphological changes is reported here. Lesions were mainly observed in the intestine. Causative for the profuse diarrhoea with emaciation was massive diffuse granulomatous enteritis involving large quantities of acid-fast organism mainly in macrophages. Granulomatous inflammation with acid-fast bacilli again in macrophages to a lesser degree could be detected in the liver. Mycobacterium avium subsp. paratuberculosis (MAP) was isolated from intestinal contents after an incubation period of four weeks. MAP-specific DNA (IS900 and f57) was detected by polymerase chain reaction in culture material. Additionally MAP-isolates were characterized by multi-target genotyping (MIRU-VNTR- and MLSSR-typing). Isolates belonged to the Type II group and exhibited a unique genotype different from other MAP strains in Germany. The donkey originated from a donkey breeding farm in France with intensive free ranging cattle in the neighbourhood and could have been infected there. Donkeys should be considered as paratuberculosis-susceptible animals in exceptional cases and as possible reservoirs or disseminators of infection.     

Methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine: a "new emerging pathogen"?

The problem of nosocomial infections is of increasing importance in veterinary medicine. As an example, this review summarizes current knowledge regarding methicillin-resistant Staphylococcus aureus (MRSA) as a typical example, as these pathogens are the most important agents of nosocomial infections in human medicine worldwide and are being increasingly reported in veterinary medicine. MRSA are classified by their ability to be resistant against oxacillin/methicillin, this feature being confered by mecA, a gene which was acquired by horizontal gene transfer of the staphylococcal gene cassette (SCCmec). It is this genetic information that enables MRSA to be resistant against all penicillins, cehalosporins and carbapenems. In addition, MRSA are often resistant against a variety of other antiinfectives, i.e. aminoglycosides, macrolides, lincosamide, streptomycins, tetracyclin, chloramphenicol, but also against fluorquinolones and rifampicin. Presumably, these highly adapted strains are particularly able to acquire resistance genes located on plasmids or transposons.They are also able to develop point mutations, further leading to resistant phenotypes. If these pathogens are leading to infectious diseases, veterinarians may be confronted with a worst-case scenario, being left without any antiinfective therapeutic. As Staphylococcus aureus is highly tenacid, professional hygiene management is of utmost importance. The increasing number of published sporadic MRSA infections, MRSA-infectious diseases as well as MRSA outbreaks in veterinary medicine justifies their recognition as a "New Emerging Pathogen". So far, horses and dogs are mostly affected by MRSA. Although transmission between humans and animals has been reported occasionally, the sources, routes of transmission or the epidemiological relevance of MRSA infections in animals are far from being understood. Therefore, epidemiological investigations utilizing molecular typing tools are mandatory. Typing tools like multilocus-sequence-typing (MLST), pulsefield-gelelectrophoresis (PFGE), sequence analysis of the gene encoding protein A (spa-typing) as well as SCCmec-typing are all at hand.     

An immunohistochemical study of the role of matrix metalloproteinases and their tissue inhibitors in chronic mitral valvular disease (valvular endocardiosis) in dogs

While the pathogenesis of chronic valvular disease (CVD) in dogs remains unclear, alterations in the activity of specific metalloproteinase enzymes and their inhibitors within the valve stroma are suspected of having a role. This study describes the immunohistochemical distribution pattern of matrix metalloproteinase (MMP) types 2, 9 and 14 and their tissue inhibitors, termed tissue inhibitors of metalloproteinase (TIMP), types 2 and 3, in normal canine mitral valves (MVs) (n=10) and in dogs with mild (n=7), moderate (n=14) and severe (n=9) CVD. In normal MVs, MMP-2 and -14, and TIMP-2 were expressed in isolated stromal cells. Tissue inhibitor of metalloproteinase-3 exhibited moderate intracellular and mild extracellular expression. With increasing severity of CVD, the expression of MMP-2 decreased. The number of stromal cells expressing MMP-14 increased, predominantly in the margins of the nodular lesions. Tissue inhibitor of metalloproteinase-2 and -3 expression increased both intra- and extracellularly. Matrix metalloproteinase-9 was not detected in normal or diseased valves. In conclusion, CVD was characterised by alterations in the distribution and intensity of valvular MMP and TIMP expression, suggesting that depressed catabolism and the accumulation of extracellular matrix components within affected valves contributes to their structural alteration and consequent loss of function.     

Diagnosis of anatoxin-a poisoning in dogs from North America.

Anatoxin-a, a toxin produced by several genera of blue-green algae, is considered a potent neurotoxin. Ingestion of water contaminated with the toxin results in acute neurological signs and often death. This report describes fatal cases of anatoxin-a ingestion in 6 dogs, with confirmation of anatoxin-a exposure by liquid chromatography/tandem mass spectrometry (LC-MS/MS/MS). In 1 outbreak, 3 dogs developed seizures and died within an hour after swimming in a river in California, while the other outbreak involved 3 dogs that died within 1 hour after swimming in a pond in Ontario. Anatoxin-a poisoning is rarely reported in dogs as a cause of acute neurological signs and death. However, increased occurrences of blue-green algae blooms in North America make this neurotoxin an important consideration in the diagnosis of sudden death associated with environmental water exposure. This brief communication reports on the isolation and detection of anatoxin-a from environmental water sources and the stomach contents of North American dogs dying of acute neurotoxicosis. This demonstrates the first documented cases of anatoxin-a poisoning in dogs in North America and the importance of LC-MS/MS/MS in identifying neurotoxins responsible for sudden death in cases of suspected blue-green algae toxicosis; especially those cases showing no gross or histological lesions.     

Effects of isoflurane upon minimum alveolar concentration and cerebral cortex depression in pigs and goats: An interspecies comparison

This study compared the effects of isoflurane in pigs (n = 10 Yorkshire–Landrace cross) and dairy goats (n = 10) by evaluation of electroencephalographic (EEG) burst suppression thresholds (BST) in the cerebral cortex and minimum alveolar concentration (MAC) values in the spinal cord. The study also investigated whether individual MAC values can predict the effects of isoflurane on the cerebral cortex. MAC values and BST/MAC ratios were significantly different between species. Inhibition of movement by isoflurane may be less effective in pigs than in goats. No significant correlation was found between individual MAC and BST values, indicating that in single animals the individual MAC poorly reflects the cerebrocortical depressant effect of isoflurane in pigs and goats.     

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts

Background  

Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations.     

Metabolic and clinical traits in horses undergoing feed deprivation for elective orthopaedic surgery

The objective of this study was to investigate some metabolic and clinical effects of feed deprivation in horses that were submitted for orthopaedic surgery. The effects of preoperative feed restriction were investigated in 20 horses submitted for elective orthopaedic surgery.The patients were fasted from 12 hours before until 4 hours after surgery. Serum free amino acids, glucose,free fatty acids (FFA), white blood cell counts, creatine kinase (CK) and aspartate aminotransferase (AST) were determined 24 hours before surgery, 2 hours after the end of anaesthesia and 24 and 72 hours after surgery. Besides, abdominal sounds, appetite, faecal quality and body temperature were examined. Serum free amino acids did not react homogenously, concentrations were partly increasing or decreasing. Plasma glucose and FFA increased after surgery and returned to their preoperative levels 72 hours after surgery. A significant rise of the segmented granulocytes occurred 24 hours after surgery, all other parameters of the leukogram did not exceed the physiological range. AST reached its highest activity 24 hours after surgery, whereas CK activities were highest at 2 hours after surgery. Abdominal sounds were significantly reduced until 24 hours after surgery, however, appetite was not depressed. Faecal quality was physiological after surgery. Mean body temperature stayed within the physiological range. In conclusion, a relatively short perioperative fasting period had significant effects on the metabolic traits in horses, however the effects on physiological functions were minor. The consequences of major surgical procedures need to be addressed in future studies.