2007 - 76 (5)

Risk analysis is becoming increasingly important in veterinary medicine and veterinary public health. It isused to inform and objectify decisions concerning the control and management of risks for animals and/or humans.These risks are often arising from complex biological systems and pathways and therefore the use of apreset methodology to describe the underlying biological systems is becoming indispensable. In a first step ofrisk analysis the hazard is identified and a well defined risk question is developed. Secondly the entire productionprocess is described and an estimation of the risk and consequences of an unwanted event is made. Based on thisinformation risk control strategies are proposed by risk managers. Finally communication concerning the risk andthe preventive measurements is very important for all stakeholders involved.

For many years dog aggression has been a matter of concern for the authorities and dog breedinggroups. In order to assess aggressive tendencies in dogs, an aggression test was developed (Netto and Planta,1997). This test consisted of 43 subtests, had to be performed in an indoor enclosure and lasted for approximately45 minutes per dog. It seemed impossible to use this test for a large population, therefore theDutch Kennel Club (Raad van Beheer) asked the first author to develop a shorter version of this test thatpreferably should be performed outdoors. The test, called the Socially Acceptable Behavior test (SAB test),consists of only 16 subtests and is performed outdoors. The definition of aggressive biting during the testincludes not only aggressive bites or snaps, but also aggressive attacks in which the dog makes a lunge in anattempt to bite, which fails because it has reached the end of its leash. In this article the validity of the testfor aggressive biting behavior is examined by analyzing the data for 330 dogs. To do so, a comparison wasmade between the test result and the aggressive biting behavior of the dogs prior to the test, as reportedby the owners and confirmed by behavioral consultants. The correspondence between the history of bitingand the aggressive biting behavior during the test is 82%, when no aggressive biting behavior at all is consideredacceptable. When the aggressive biting behavior is allowed in maximum one of 8 specified subtests,in biting behavior is allowed in maximum one of 8 specified, the correspondence raises to 88%, and of the27 false negatives (28.7%) 18 dogs performed only territorial aggression prior to the test.In the second phase, the predictability of aggressive biting behavior towards people, as shown in the test,is calculated by comparing the test results of 220 dogs with the aggressive biting behavior of these dogsshown in a period of at least 1 year after the test, as reported by the owners. The predictability is 81.8%.The test can be considered to predict in a statistically significant way the occurrence of future aggressivebiting behavior of dogs towards unfamiliar people in a non-territorial context in the first year after the test.The existence of false negative results means that the assumption that a dog that passes the test will neverbite later is not correct, as aggression is often very contextual. The value of the individual test is that it supplementsthe other evaluation methods in terms of behavioral consultation and risk evaluation. Furtherinvestigation is necessary to compare a dog’s individual result to its behavior over a longer period later inlife and to investigate the use of the test as a tool in breeding programs.

This paper describes the first confirmed case of ryegrass staggers in horses from a riding school in Belgium. Duringthe last days of February 2007 about thirty horses showed variable neurological symptoms, such as anxiety,muscle fasciculations, hypermetria and ataxia. The diagnosis of ryegrass staggers was made based on the clinicalsymptoms, the anamnesis which stated that perennial ryegrass hay imported from France had been fed to theanimals since a few days, and on the demonstration of a high lolitrem concentration in the hay. No horses dieddespite of the high morbidity: all horses recovered completely three days after withdrawal of the hay.

Listeria monocytogenes can cause disease and death in humans and a large variety of animal species.Canine listeriosis seems, however, to be rare. In the present report, L. monocytogenes was isolated as apure culture from the gallbladder of a dog with liver insufficiency. The animal suffered from auto-immune-mediated polyarthritis and had therefore been treated with prednisolone for several months. The L.monocytogenes isolate tested positive in PCR for the virulence genes inlA, inlB, hly, actA, sigB and prfA andexpressed functional, full-length internalin. This is the first reported case of a dog with a L. monocytogenesinfection of the gallbladder. Bacterial persistence in the gallbladder of pet animals may constitute a healthhazard for their owner.

Three neonatal Belgian white and red calves with a thickened and rigid skin, characterized by the presenceof scaly plates separated by deep reddened fissures were presented for necropsy. The least affectedcalf still had a normal hair coat, whilst the other two cases were alopecic and additionally displayed eclabium,ectropion and microtia. Based on these findings, ichthyosis fetalis bovis was diagnosed. Histologicalexamination of skin samples obtained after euthanasia revealed an exuberant orthokeratotic hyperkeratosisof the stratum corneum. In human harlequin ichthyosis, a disorder highly resembling bovineichthyosis fetalis, a defective lipid transport in keratinocytes caused by a single locus autosomal recessivegene defect has recently been identified as the cause of the disorder. Pedigree information of the calvescombined with additional information of three other calves of the same breed allowed the identificationof 3 disease carrying bulls and suggests an autosomal recessive inheritance of bovine ichthyosis fetalis. Asthere is currently no cure for this lethal disease, a proper breeding program is the only option to minimizethe incidence of ichthyosis in this specific cattle breed.

Paper in Dutch

Paper in Dutch

Because of the non-specificity of the clinical signs and laboratory findings, imaging techniques suchas portography, ultrasonography (US), nuclear scintigraphy, computed tomography (CT), or magneticresonance imaging (MRI) are required to provide a definitive diagnosis of portosystemic shunts (PSSs).Nuclear scintigraphy is the gold standard for detecting PSSs, but it is not useful in distinguishing the differenttypes of shunts. Due to its high sensitivity, portography has for a long time been considered the goldstandard for differentiation of PSSs, despite its invasive nature. However, the recent development of astandard protocol for US and the routine use of Doppler modalities have resulted in the same sensitivityas portography. Therefore, with the additional benefit of being fast and noninvasive, US is now more commonlyperformed. It may be considered a “new” gold standard, depending upon the experience of theradiologist. Computed tomography and MRI provide detailed anatomic information. In this fourth articleabout portosystemic shunts in dogs and cats a comprehensive overview of the literature covering US andnuclear scintigraphy will be given. Finally CT and MRI techniques will be explained briefly.

Portosystemic shunts (PSSs) are anomalous vascular communications between the portal vein or itsbranches and the systemic venous system. Signalment, history, clinical signs, and laboratory findings canalready provide a presumptive diagnosis of a PSS. However, imaging techniques such as portography,ultrasonography (US), nuclear scintigraphy, computed tomography (CT), or magnetic resonance imaging(MRI) are required to provide a definitive diagnosis. Nuclear scintigraphy is the gold standard for detectingPSSs, but it is not useful in distinguishing the different types of shunts. Due to its high sensitivity,portography was for a long time considered the gold standard for the differentiation of PSSs, even thoughit is an invasive technique. However, the recent development of a standard protocol for ultrasound (US)and the routine use of Doppler modalities resulted in the same sensitivity as portography. Therefore, withthe additional benefit of being fast and noninvasive, US is now more commonly performed. It may be suggestedas a “new” gold standard, depending upon the experience of the radiologist. Computed tomographyand MRI provide detailed anatomic information. In this third part about portosystemic shunts in dogs andcats the different types of shunts and their diagnosis using portography will be explained.