Evaluation of antibody-ELISA and real-time RT-PCR for the diagnosis and profiling of bluetongue virus serotype 8 during the epidemic in Belgium in 2006

In 2006 bluetongue (BT) emerged for the first time in North-Western Europe. Reliable diagnostic tools are essential in controlling BT but data on the diagnostic sensitivity (Se) and specificity (Sp) are often missing. This paper aims to describe and analyse the results obtained with the diagnostics used in Belgium during the 2006 BT crisis. The diagnosis was based on a combination of antibody detection (competitive ELISA, cELISA) and viral RNA detection by real-time RT-PCR (RT-qPCR). The performance of the cELISA as a diagnostic tool was assessed on field results obtained during the epidemic and previous surveillance campaigns. As the infectious status of the animals is unknown during an epidemic, a Bayesian analysis was performed. Both assays were found to be equally specific (RT-qPCR: 98.5%; cELISA: 98.2%) while the diagnostic sensitivity of the RT-qPCR (99.5%) was superior to that of the cELISA (87.8%). The assumption of RT-qPCR as standard of comparison during the bluetongue virus (BTV) epidemic proved valid based on the results of the Bayesian analysis. A ROC analysis of the cELISA, using RT-qPCR as standard of comparison, showed that the cut-off point with the highest accuracy occurred at a percentage negativity of 66, which is markedly higher than the cut-off proposed by the manufacturer. The analysis of the results was further extended to serological and molecular profiling and the possible use of profiling as a rapid epidemiological marker of the BTV in-field situation was assessed. A comparison of the serological profiles obtained before, during and at the end of the Belgian epidemic clearly showed the existence of an intermediate zone which appears soon after BTV (re)enters the population. The appearance or disappearance of this intermediate zone is correlated with virus circulation and provides valuable information, which would be entirely overlooked if only positive and negative results were considered.     

Prevalence and identification of fungal DNA in the small intestine of healthy dogs and dogs with chronic enteropathies

Limited information is available about the prevalence and phylogenetic classification of fungal organisms in the gastrointestinal tract of dogs. Also, the impact of fungal organisms on gastrointestinal health and disease is not well understood. The aim of this study was to evaluate the prevalence of fungal DNA in the small intestine of healthy dogs and dogs with chronic enteropathies. Small intestinal content was analyzed from 64 healthy and 71 diseased dogs from five different geographic locations in Europe and the USA. Fungal DNA was amplified with panfungal primers targeting the internal transcriber spacer (ITS) region. PCR amplicons were subjected to phylogenetic analysis. Fungal DNA was detected in 60.9% of healthy dogs and in 76.1% of dogs with chronic enteropathies. This prevalence was not significantly different between the two groups (p=0.065). Fungal DNA was significantly more prevalent in mucosal brush samples (82.8%) than in luminal samples (42.9%; p=0.002). Sequencing results revealed a total of 51 different phylotypes. All sequences belonged to two phyla and were classified as either Ascomycota (32 phylotypes) or Basidiomycota (19 phylotypes). Three major classes were identified: Saccharomycetes, Dothideomycetes, and Hymenomycetes. The most commonly observed sequences were classified as Pichia spp., Cryptococcus spp., Candida spp., and Trichosporon spp. Species believed to be clinically more important were more commonly observed in diseased dogs. These results indicate a high prevalence and diversity of fungal DNA in the small intestine of both healthy dogs and dogs with chronic enteropathies. The canine gastrointestinal tract of diseased dogs may harbor opportunistic fungal pathogens.     

Protection des végétaux avec et sans risques

La protection des végétaux dans sa forme classique est comparée à la lutte intégrée sous l'angle de la rentabilité. La lutte doit être fondée sur la densité de population des ravageurs dont les fluctuations sont bien reflétées par un pendule mathématique qui oscille sur une échelle logarithmique. A l'aide de ce modèle il est démontré que l'emploi réduit de produits chimiques assure de meilleures récoltes. En outre, la lutte intégrée est d'un prix de revient moins élevé et elle compotte moins de risques d'échec.     

Serum Pancreatic Lipase Immunoreactivity Concentrations in Dogs Treated with Potassium Bromide and/or Phenobarbital

Potassium bromide, phenobarbital, or a combination of both is commonly used in the treatment of canine epilepsy. Several cases of clinical pancreatitis have been reported in dogs after treatment with potassium bromide, but the risk of elevated serum canine pancreatic lipase immunoreactivity concentrations in dogs treated with potassium bromide and/or phenobarbital has not previously been evaluated in a large group of dogs. This study suggests an increased risk for elevated serum canine pancreatic lipase immunoreactivity concentrations and possibly pancreatitis in dogs treated with potassium bromide or phenobarbital alone or in combination.     

Screening for Rift Valley fever infection in northern Somalia: a GIS based survey method to overcome the lack of sampling frame

Following repeated import bans imposed by Saudi Arabia on livestock originated from Somalia due to suspicion of Rift Valley fever (RVF) presence and the severe socio-economic consequences of this, it was imperative for the Somaliland government to carry out surveillance activities in order to determine the status of transboundary diseases in its territory. A GIS computer software (Arcview) was used to overcome the lack of lists of sampling sites due to the high mobility of pastoral nomadic herds in the study area. This method proved very convenient and flexible for the random selection of sampling sites and thus the compliance with the requirements by the World Organisation for Animal Health (OIE) for statistically valid methods if the surveillance outcome is to meet international recognition and acceptance. Screening in Somaliland in 2001 and in Puntland in 2003 which targeted mainly sheep and goats aged 1-2 years (97% of surveyed animals) revealed no signs compatible with the disease but an overall sero-prevalence of 2+/-0.02% (90/4570) and 5+/-0.3% (206/4050), respectively. The spatial distribution showed clusters of high sero-prevalence located mostly in the Nugal Valley. This trend was confirmed by the follow-up survey implemented in Somaliland in 2004 with a herd prevalence of 80+/-6% and a within-herd prevalence up to 50% located again in the Nugal Valley. This result suggests the maintenance and increase of RVF virus activity in the valley. In addition conditions favourable to the breeding and survival of the vector population and the high density of livestock make the Nugal Valley an area of high risk for a RVF outbreak where sentinel herds will be placed.     

Epidemiology and risk factors of cecal dilatation/dislocation and abomasal displacement in dairy cows]

The aims of the study were to determine the prevalence of cecal dilatation/dislocation (CDD) and abomasal displacement (DA) in Switzerland, to identify risk factors for both diseases, and to compare directly their epidemiologic situation. The epidemiologic study included 158 cases of CDD and 149 cases of DA from the cases referred to both University Clinics of Berne and Zurich. The results showed that DA was associated with nutrition-related risk factors: use of minerals and sodium chloride, inadequate concentrate feeding and beginning of the feeding. Furthermore, breed was significantly associated with DA, but not with CDD. Finally, milk yield and pasture were also significantly included in the models. For CDD, nutrition-related risk factors were also found: pasture in summer, use of corn pellets and corn silage in winter. In the final model, protein concentrate was also included. Although both diseases were found at comparable frequencies, the results of this study indicate marked differences between the epidemiology of occurrence of CDD and DA. Therefore, the hypothesis of a common etiopathogenesis appears unlikely.