Epidemiosurveillance of rare events in belgian cattle

Epidémiosurveillance des événements rares chez les bovins en Belgique. Thèse de doctorat en sciences vétérinaires défendue le 29 septembre 2004

Importance des facteurs de risque dans l’expression clinique des maladies infectieuses chez les ruminants

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New insight in lymnaeid snails (Mollusca, Gastropoda) as intermediate hosts of Fasciola hepatica (Trematoda, Digenea) in Belgium and Luxembourg

<b>Background</b><p></p> The present study aims to assess the epidemiological role of different lymnaeid snails as intermediate hosts of the liver fluke Fasciola hepatica in Belgium and Luxembourg.<p></p> <b>Methods</b><p></p> During summer 2008, 7103 lymnaeid snails were collected from 125 ponds distributed in 5 clusters each including 25 ponds. Each cluster was located in a different biogeographic area of Belgium and Luxembourg. In addition, snails were also collected in sixteen other biotopes considered as temporary wet areas. These snails were identified as Galba truncatula (n = 2474) (the main intermediate host of F. hepatica in Europe) and Radix sp. (n = 4629). Moreover, several biological and non-biological variables were also recorded from the different biotopes. DNA was extracted from each snail collected using Chelex® technique. DNA samples were screened through a multiplex PCR that amplifies lymnaeid internal transcribed spacer 2 gene sequences (500–600 bp) (acting as an internal control) and a 124 bp fragment of repetitive DNA from Fasciola sp.<p></p> <b>Results</b><p></p> Lymnaeid snails were found in 75 biotopes (53.2%). Thirty individuals of G. truncatula (1.31%) and 7 of Radix sp. (0.16%) were found to be positive for Fasciola sp. The seven positive Radix sp. snails all belonged to the species R. balthica (Linnaeus, 1758). Classification and regression tree analysis were performed in order to better understand links and relative importance of the different recorded factors. One of the best explanatory variables for the presence/absence of the different snail species seems to be the geographic location, whereas for the infection status of the snails no obvious relationship was linked to the presence of cattle.<p></p> <b>Conclusions</b><p></p> Epidemiological implications of these findings and particularly the role of R. balthica as an alternative intermediate host in Belgium and Luxembourg were discussed

Emergence of bluetongue due to virus serotype 8 in Belgium

peer reviewedThe emergence of Bluetongue, due to the virus of serotype 8 (BTV-8) was an unexpected event in Belgium. This vector-borne disease is caused by a virus belonging to the family of Reoviridae, genus Orbivirus whose genome consists of 10 double-stranded RNA segments. During this emergence, the virulence of the BTV-8 was exacerbated in bovines and was expressed by the appearance of severe clinical signs and reproductive disorders. The contribution of the Unit of research in epidemiology and risk analysis applied to veterinary sciences (UREAR-U.Lg.) consisted of the description, the understanding and the analysis of the particular profile which was observed during this emergence. This understanding required both field studies and a series of experimental infections in high containment facilities. Overall, emergent animal diseases have been of particular importance these last few years and represent unprecedented health, socio-economic, international, biological, partnership and media challenges

Classification of worldwide bovine tuberculosis risk factors in cattle: a stratified approach

The worldwide status of bovine tuberculosis (bTB) as a zoonosis remains of great concern. This article reviews the main risk factors for bTB in cattle based on a three-level classification: animal, herd and region/country level. A distinction is also made, whenever possible, between situations in developed and developing countries as the difference of context might have consequences in terms of risk of bTB. Recommendations are suggested to animal health professionals and scientists directly involved in the control and prevention of bTB in cattle. The determination of Millenium Development Goals for bTB is proposed to improve the control/eradication of the disease worldwide

Feline herpesvirus 1 and feline calicivirus infections in a heterogeneous cat population of a rescue shelter.

Feline herpesvirus 1 (FeHV-1) and feline calicivirus (FCV), associated with upper respiratory tract disease, are highly prevalent in cats worldwide. With the aim to investigate the importance of feline respiratory viruses in a heterogeneous population of cats, samples were taken in a rescue shelter in Liege, Belgium, between March 2005 and August 2006. Reverse transcription polymerase chain reaction (RT-PCR) and polymerase chain reaction (PCR) were performed to diagnose FCV and FeHV-1 infection in the sampled cats. The prevalence rate (33.1%) was higher for FCV than for FeHV-1 (20.1%) whereas prevalence rate of co-infection with both viruses was 10%. Gingivitis was more common in FCV infections (odds ratio (OR)=2.83) whereas respiratory signs were more often observed with FeHV-1 infections. The average age was significantly higher in FCV positive cats (38 months) than in FeHV-1 positive cats (29.9 months). The second and the fourth quarters of the year and the two first quarters were significantly more at risk than the others in the case of FeHV-1 and FCV infection, respectively. Age was found to be a confounding factor. High prevalence of both infections strengthens the importance of applying hygienic and preventive measures in rescue shelters where cats with an unknown status of vaccination are introduced.Peer reviewe

Internal audits as a tool to assess the compliance with biosecurity rules in a veterinary faculty.

peer reviewed[en] INTRODUCTION: The present paper proposes a tool to follow up the compliance of staff and students with biosecurity rules, as enforced in a veterinary faculty, i.e., animal clinics, teaching laboratories, dissection rooms, and educational pig herd and farm. METHODS: Starting from a generic list of items gathered into several categories (personal dress and equipment, animal-related items, infrastructures, waste management, management of material/equipment and behavior), a checklist was created for each sector/activity mentioned above, based on the rules and procedures compiled in the Faculty biosecurity standard operating procedures. Checklists were created as Excel™ files. For each sector, several sheets were elaborated, i.e., one per specific activity: for example, the following sheets were created for the equine clinic: class 1-2 hospitalization (class 1 = non-infectious conditions; class 2 = infectious disease with a low or non-existent risk of transmission), class 3 hospitalization (class 3 = infectious disease with a moderate risk of transmission; these patients are suspected of having an infectious disease and being contagious for other patients and/or for humans) and consultation. RESULTS: Class 4 area, which corresponds to the isolation unit and aims at housing patients suffering from infectious diseases with a significant risk of transmission (including notifiable conditions), was not audited at that period, as it was undergoing renovation works. The audit relied on observations performed by a unique observer to ensure standardization. Observed items were presented as yes/no and multiple-choice questions. A scale from 0 to 3 or 4 (depending on the item) allowed scoring each item, i.e., 0 corresponding to 100% compliance with the procedure and the highest score to the worst situation. A median and average global score was also estimated by category and by activity. DISCUSSION: The methodology described in the present paper allows estimating the compliance with biosecurity standard operating procedures in a specific sector and/or for a given activity. The identification of criteria needing improvement is a key point: it helps prioritizing actions to be implemented and awareness raising among people concerned. Regular internal auditing is an essential part of a biosecurity plan, the frequency being conditioned by the risk linked to a specific activity or area (i.e., more frequent audits in risky situations)

A SYBR Green RT-PCR assay in single tube to detect human and bovine noroviruses and control for inhibition

BACKGROUND: Noroviruses are single-stranded RNA viruses belonging to the family Caliciviridae. They are a major cause of epidemic and sporadic gastroenteritis in humans and clinical signs and lesions of gastroenteritis were reported in bovines. Due to their genetic proximity, potential zoonotic transmission or animal reservoir can be hypothesized for noroviruses. RT-PCR has become the "gold standard" for the detection of noroviruses in faecal and environmental samples. With such samples, the control for inhibition of the reaction during amplification and detection is crucial to avoid false negative results, which might otherwise not be detected. The aim of the reported method is to detect, with a SYBR Green technology, a broad range of noroviruses with a control for inhibition. RESULTS: A SYBR Green real-time RT-PCR assay was developed making use of a foreign internal RNA control added in the same tube. This assay is able to detect human and bovine noroviruses belonging to genogroups I, II and III and to distinguish between norovirus and internal control amplicons using melting curve analysis. A 10-fold dilution of samples appears to be the method of choice to remove inhibition. This assay was validated with human and bovine stool samples previously tested for norovirus by conventional RT-PCR. CONCLUSION: This SYBR Green real-time RT-PCR assay allows the detection of the most important human and bovine noroviruses in the same assay, and avoids false negative results making use of an internal control. Melting curves allow the discrimination between the internal control and norovirus amplicons. It gives preliminary information about the species of origin. The sensitivity of the developed assay is higher than conventional RT-PCR and a 10-fold dilution of samples showed a better efficiency and reproducibility to remove RT-PCR inhibition than addition of bovine serum albumin