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See detailBreeding Sites Of Bluetongue Vectors In Northern Europe
Zimmer, Jean-Yves ULg; Haubruge, Eric ULg; Francis, Frédéric ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2008), 162(4), 131

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See detailDistribution Of Potential Bluetongue Vectors On Belgium Farms
Zimmer, Jean-Yves ULg; Haubruge, Eric ULg; Francis, Frédéric ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2008), 162(21), 700

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See detailBiologie et écologie des culicoïdes (Diptera), vecteurs de la fièvre catarrhale ovine
Zimmer, Jean-Yves ULg; Losson, Bertrand ULg; Haubruge, Eric ULg

in Entomologie Faunistique = Faunistic Entomology (2008), 61(1-2), 53-57

The ovine catarrhal fever (FCO) caused considerable economic losses on the Belgian sheep and cattle livestock during the year 2007. The biological vectors of the bluetongue virus (BTV) are diptera ... [more ▼]

The ovine catarrhal fever (FCO) caused considerable economic losses on the Belgian sheep and cattle livestock during the year 2007. The biological vectors of the bluetongue virus (BTV) are diptera belonging to the genus Culicoides. Their survival, their activity and their distribution depend on many variables still relatively unknown. The setting up of an effective control strategy against these biting midges requires a better knowledge of their biology and their ecology, as well as adult status as larval one. This control strategy against Culicoides biting midges can be combined with some hygienic measures in farming, reinforcing the vaccination programme of Belgian cattle against FCO serotype 8. [less ▲]

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See detailSecreted subtilisins of Microsporum canis are involved in adhesion of arthroconidia to feline corneocytes
Mathy, Anne ULg; Tabart, Jérémy; Mignon, Bernard ULg et al

Poster (2008)

Microsporum canis is a pathogenic fungus that causes a superficial skin infection called dermatophytosis mainly in cats, dogs and humans. Like other dermatophytoses, the physiopathology of this dermatosis ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial skin infection called dermatophytosis mainly in cats, dogs and humans. Like other dermatophytoses, the physiopathology of this dermatosis remains largely unknown. From a fungal perspective, the infection process can be divided in three steps: adhesion of M. canis arthroconidia to corneocytes, conidial germination, and fungal invasion of the keratin network. The mechanisms involved in adherence of M. canis to epidermis have never been investigated. However, several previously characterized secreted fungal endoproteases like subtilisins (Sub), including the keratinolytic protease Sub3, are secreted in vivo and could be involved in the first pathogenic steps. The objective of this study were (1) to develop an in vitro model to study M. canis adherence to feline corneocytes and (2) to assess whether the Sub are involved in fungal adhesion. An arthroconidial suspension was spread over the surface of reconstituted feline epidermis (RFE). Co-cultures were incubated for varying lengths of time and adherent conidia were labelled using Calcofluor white and counted. In subsequent assays arthroconidia were exposed to the serine protease inhibitor chymostatin or a mixture of two anti-Sub3 monoclonal antibodies (Mabs) one hour prior to the adherence assay. In our model, adherence of M. canis arthroconidia to RFE is time-dependent, beginning within two hours and still increasing after six hours. Chymostatin and Mabs inhibit M. canis adherence to RFE by 53 and 23 % respectively, which suggests that subtilisins and particularly Sub3, are fungal virulence factors involved in the adherence process. [less ▲]

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See detailPathogenesis of dermatophytosis
Vermout, Sandy; Tabart, Jeremy; Baldo, Aline ULg et al

in Mycopathologia (2008), 166(5-6), 267-275

Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to ... [more ▼]

Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to characterize secreted dermatophytic proteases at the molecular level, only punctual insights have been afforded into other aspects of the pathogenesis of dermatophytosis, such as fungal adhesion, regulation of gene expression during the infection process, and immunomodulation by fungal factors. However, new genetic tools were recently developed, allowing a more rapid and high-throughput functional investigation of dermatophyte genes and the identification of new putative virulence factors. In addition, sophisticated in vitro infection models are now used and will open the way to a more comprehensive view of the interactions between these fungi and host epidermal cells, especially keratinocytes. [less ▲]

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See detailReconstructed interfollicular feline epidermis as a model for the screening of antifungal drugs against Microsporum canis.
Tabart, Jeremy; Baldo, Aline ULg; Vermout, Sandy et al

in Veterinary Dermatology (2008), 19(3), 130-133

A fully differentiated reconstructed interfollicular feline epidermis (RFE) was recently developed in vitro. It was shown to be relevant for the study of Microsporum canis-epidermal interactions. In this ... [more ▼]

A fully differentiated reconstructed interfollicular feline epidermis (RFE) was recently developed in vitro. It was shown to be relevant for the study of Microsporum canis-epidermal interactions. In this study, RFE was evaluated as a potential model for the in vitro screening of drugs against M. canis. As a preliminary step, the minimum inhibitory concentration of miconazole nitrate against M. canis IHEM 21239 grown on Sabouraud's dextrose agar was determined to be 0.3 microg mL(-1). RFE grown at the air-liquid interface was cultured for 24 h in RFE culture medium, supplemented with either miconazole (range 0.1-1 microg mL(-1)) or its solvent (dimethylsulfoxide). Then, RFE was inoculated in triplicate with 1 x 10(5 )M. canis arthroconidia and incubated for five additional days. To evaluate fungal growth, RFE was processed for routine histopathology, three serial sections being performed across the block at 100 microm intervals. No fungal growth was detected invading or on the surface of infected RFE in the presence of miconazole concentrations equal to or higher than 0.3 microg mL (final concentration in the culture medium). This study demonstrates that RFE is an adequate model for the in vitro screening of drugs against M. canis and potentially against other skin pathogens. [less ▲]

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See detailSecreted subtilisins of Microsporum canis are involved in adherence of arthroconidia to feline corneocytes.
Baldo, Aline ULg; Tabart, Jeremy; Vermout, Sandy et al

in Journal of Medical Microbiology (2008), 57(Pt 9), 1152-1156

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis, mainly in cats and humans. The mechanisms involved in adherence of M. canis to epidermis have ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis, mainly in cats and humans. The mechanisms involved in adherence of M. canis to epidermis have never been investigated. Here, a model was developed to study the adherence of M. canis to feline corneocytes through the use of a reconstructed interfollicular feline epidermis (RFE). In this model, adherence of arthroconidia to RFE was found to be time-dependent, starting at 2 h post-inoculation and still increasing at 6 h. Chymostatin, a serine protease inhibitor, inhibited M. canis adherence to RFE by 53%. Moreover, two mAbs against the keratinolytic protease subtilisin 3 (Sub3) inhibited M. canis adherence to RFE by 23%, suggesting that subtilisins, and Sub3 in particular, are involved in the adherence process. [less ▲]

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See detailVector monitoring at Belgian outbreak sites during the bluetongue epidemic of 2006.
De Deken, G.; Madder, M.; Deblauwe, I. et al

in Preventive Veterinary Medicine (2008), 87(1-2), 64-73

In response to the first bluetongue outbreak in Belgium a monitoring programme was started at the end of August 2006 to identify possible vectors transmitting the disease. Black light traps were deployed ... [more ▼]

In response to the first bluetongue outbreak in Belgium a monitoring programme was started at the end of August 2006 to identify possible vectors transmitting the disease. Black light traps were deployed at 36 outbreak sites and captured 1959 Culicoides specimens belonging to 16 different species. Eighty four percent of the biting midges captured belonged to the C. obsoletus complex, among them C. obsoletus s.s., C. dewulfi and C. scoticus, three suspected bluetongue vectors. The Veterinary and Agrochemical Research Centre detected viral RNA in pools of individuals belonging to this complex. Culicoides pulicaris, a potential bluetongue vector in Italy, should yet not be excluded as a possible vector in Belgium as this species was frequently found around outbreak sites, notwithstanding this species is not easily captured with the trapping techniques used during this survey. [less ▲]

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See detailCulicoides trapping with Rothamsted suction traps before and during the bluetongue epidemic of 2006 in Belgium.
Fassotte, C.; Delecolle, J. C.; Cors, R. et al

in Preventive Veterinary Medicine (2008), 87(1-2), 74-83

The collection of biting midges was taking place some months before the first bluetongue outbreak in Belgium in August 2006. The Walloon Agricultural Research Centre had been monitoring aphid populations ... [more ▼]

The collection of biting midges was taking place some months before the first bluetongue outbreak in Belgium in August 2006. The Walloon Agricultural Research Centre had been monitoring aphid populations at two sites annually in Belgium (Gembloux and Libramont), using two stationary '12-m' Rothamsted suction traps. For the Gembloux trap, collections of insects captured daily from 11 May 2006 onwards were already available at the time of the outbreak. An examination of these samples revealed the presence of Culicoides, some species of which are considered as potential vectors of the bluetongue virus (BTV). The trapping was therefore extended beyond the normal aphid activity period and the Culicoides captured were identified to species level. From 11 May to 31 December 2006, the Gembloux trap caught 664 Culicoides specimens belonging to 19 species comprising known BTV-vectors. The second trap, at Libramont, was reactivated from 12 September to 13 October and caught 97 specimens belonging to nine species, all of which had been found at the Gembloux site. Among the 19 species identified, four were new to Belgian fauna: Culicoides achrayi, C. deltus, C. lupicaris and C. newsteadi. This paper examines the overall phenology and the physiological status of Culicoides in 2006 before and during the bluetongue epidemic. It discusses the potential of the Rothamsted suction trap to monitor Culicoides. [less ▲]

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See detailDetection of Neospora caninum in dog organs using real time PCR systems.
Ghalmi, F.; Losson, Bertrand ULg; Daube, Georges ULg et al

in Veterinary Parasitology (2008), 155

Neospora caninum is a parasite responsible for paresis in dogs. The dog can harbour enkysted parasites in several organs. The detection of N. caninum was performed using 3 different real time PCR systems ... [more ▼]

Neospora caninum is a parasite responsible for paresis in dogs. The dog can harbour enkysted parasites in several organs. The detection of N. caninum was performed using 3 different real time PCR systems all amplifying the NC5 DNA region. One system was based on Sybr1green, one on PlexorTM technology and the last on Taqman1 probe. Comparison of the three methods indicated that the detection limit was 1 equivalent genome on pure DNA but that this detection limit increased in the presence of foreign DNA using the Sybrgreen and Plexor systems. Therefore, the Taqman system was chosen to detect N. caninum in liver and spleen of naturally infected dogs. The overall prevalence was 32.2%. Comparison between PCR results and serological results using IFAT showed that among the 28 PCR positive dogs only 9 were seropositive and that 8 seropositive dogs were PCR negative. Therefore serology can underestimate the real carriage in dogs. However, PCR methods must be improved in terms of sensitivity and inhibition problems. [less ▲]

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See detailSecreted dipeptidyl peptidases as potential virulence factors for Microsporum canis.
Vermout, Sandy; Baldo, Aline ULg; Tabart, Jeremy et al

in FEMS Immunology & Medical Microbiology (2008), 54(3), 299-308

Dermatophytoses caused by Microsporum canis are frequently encountered in cats and dogs; they are highly contagious and readily transmissible to humans. In this study, two single genes, respectively ... [more ▼]

Dermatophytoses caused by Microsporum canis are frequently encountered in cats and dogs; they are highly contagious and readily transmissible to humans. In this study, two single genes, respectively coding for dipeptidyl peptidases IV and V (DppIV and DppV), were isolated and characterized. Both proteins share homology with serine proteases of the S9 family, some of which display properties compatible with implication in pathogenic processes. Both genes are expressed in vivo in experimentally infected guinea-pigs and in naturally infected cats, and when the fungus is grown on extracellular matrix proteins as the sole nitrogen and carbon source. DppIV and V were produced as active recombinant proteases in the yeast Pichia pastoris; the apparent molecular weight of rDppV is 83 kDa, whereas rDppIV appears as a doublet of 95 and 98 kDa. Like other members of its enzymatic subfamily, rDppIV has an unusual ability to cleave Pro-X bonds. This activity does not enhance the solubilization of keratin by fungal secreted endoproteases, and the protease probably acts solely on small soluble peptides. RDppV showed no ability to induce delayed-type hypersensitivity (DTH) skin reactions in guinea-pigs, despite the known immunogenic properties of homologous proteins. [less ▲]

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See detailLes nouveaux antiparasitaires chez le chien et le chat
Losson, Bertrand ULg

in Nouveau praticien vétérinaire (2008)

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See detailPathogenicity and thermotolerance of entomopathogenic fungi for the control of the scab mite, Psoroptes ovis.
Lekimme, Mireille ULg; Focant, Charles ULg; Farnir, Frédéric ULg et al

in Experimental & Applied Acarology (2008), 46(1-4), 95-104

Psoroptes ovis is responsible for a highly contagious skin condition, both in sheep and cattle. This parasite has a marked economical impact in the sheep and cattle industry. Biological control is ... [more ▼]

Psoroptes ovis is responsible for a highly contagious skin condition, both in sheep and cattle. This parasite has a marked economical impact in the sheep and cattle industry. Biological control is considered as a realistic alternative to chemotherapeutic control. Laboratory experiments were carried out to evaluate the pathogenicity and the thermotolerance of twelve isolates of entomopathogenic fungi from four genera (Beauveria Vuillemin, Metarhizium Sorokin, Paecilomyces Bainier and Verticillium Nees). The pathogenicity was evaluated by the survival of P. ovis females after exposure to 10(6) to 10(8) conidia ml(-1) in humidity chambers. Results revealed intra- and interspecies differences. All isolates with the exception of B. bassiana IHEM3558 and V. lecanii MUCL8672 induced 50% mortality within 2 days at the highest concentration. At this concentration the entire mite population became infected with all isolates but B. bassiana IHEM3558; however, only four isolates gave rise to 100% infected cadavers at the lowest concentration. The thermotolerance of each isolate was evaluated by measuring its growth on an artificial medium kept between 25 and 37.5 degrees C. All isolates were able to grow up to 30 degrees C but only two, M. anisopliae IHEM18027 and Paecilomyces farinosus MUCL18885, tolerated temperatures up to 35 degrees C. These two isolates could be considered as good candidates for further use as biopesticide taking into account their virulence and thermotolerance. Other critical factors linked with the implementation of this type of biocontrol in P. ovis infected animals are discussed. [less ▲]

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See detailEvolution of the clinical expression of Bluetongue in Belgian cattle during year 2006 vs 2007
Guyot, Hugues ULg; Mauroy, Axel ULg; Rollin, Frédéric ULg et al

Conference (2008)

In August 2006, Belgium notified its first cases of Bluetongue (BT), serotype 8, in cattle and sheep. The disease was also observed at this time in the neighboring countries. The resurgence of BT was ... [more ▼]

In August 2006, Belgium notified its first cases of Bluetongue (BT), serotype 8, in cattle and sheep. The disease was also observed at this time in the neighboring countries. The resurgence of BT was observed in Northern Europe in 2007. The aim of the study was to compare clinical signs of BT observed in 2006 vs 2007 in Belgian cattle. The description of clinical signs was based on the observation of 38 and 39 cows in 2006 and 2007, respectively. BT cases were only included if they were confirmed by one or both laboratory diagnostic tests (competitive ELISA test and/or RT-qPCR). The inventory of clinical signs was made with a standardised clinical form for BT. This form is divided into general, cutaneous, locomotor, digestive, respiratory, neurological and reproductive clinical signs. Case data were summarised to determine changes in clinical presentation of BT between 2006 and 2007. A Fischer’s exact probability test was performed to compare (P<0.05) the frequency of clinical signs between the two years. Regarding general clinical signs, hyperthermia and tiredness were more often observed in 2007, compared to 2006. All clinical signs about skin and annexes were not significantly different between the two years. Locomotor signs such as prostration, incapacity to get up, reluctance to move, lameness and amyotrophy were more frequent in 2007. Loss of appetite, difficulties in grasping feed, salivation and drooling were the digestive signs more often observed in 2007. A purulent nasal discharge was the only respiratory sign more commonly observed in 2007. Apathy, generalised weakness and paresis or paralysis were more often encountered in 2007. The most important changes between the two years concerned reproduction. A higher incidence of abortion, premature calving and stillbirth was observed during 2007 outbreak. The frequency of most of the clinical signs of BT was higher in 2007 in Belgian cattle. Confirmed cases of BT in Belgian cattle were only 296 in 2006 compared to 4187 in 2007. These data do not represent the real situation of BT infection because the farmers do not notify all cases. Nevertheless, it seems that the 2007 outbreak was more severe regarding the number of cases and the frequency of clinical signs. The mild winter and wet 2007 summer might have favored the persistence of the vectors. [less ▲]

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See detailFasciola hepatica: an assessment on the vectorial capacity of Radix labiata and R. balthica commonly found in Belgium.
Caron, Yannick ULg; LASRI, Saadia ULg; Losson, Bertrand ULg

in Veterinary Parasitology (2007, October 21), 149(1-2), 95-103

A previous study conducted in Belgium revealed that genetic material of Fasciola sp. was present in snail species belonging to the genus Radix. Here, these snails were collected and identified by DNA ... [more ▼]

A previous study conducted in Belgium revealed that genetic material of Fasciola sp. was present in snail species belonging to the genus Radix. Here, these snails were collected and identified by DNA-based techniques as Radix labiata and Radix balthica. These two species and Galba truncatula (the major intermediate host in Europe) were experimentally infected with Fasciola hepatica. The resulting metacercariae were fed to rats and the infection was monitored using several techniques. Microscopy revealed the presence of larval stages in 78.3, 45, and 6.25% of G. truncatula, R. labiata, and R. balthica snails, respectively. These results were confirmed by a PCR that amplifies a Fasciola sp. specific sequence. Furthermore, this PCR was found to be more sensitive than microscopic examination. R. labiata shed fewer metacercariae than G. truncatula but these were as infective to rats as those shed by G. truncatula. This study demonstrates that R. labiata may act as an incidental intermediate host for F hepatica in Belgium. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailRNA silencing in the dermatophyte Microsporum canis
Vermout, S.; Tabart, J.; Baldo, Aline ULg et al

in FEMS Microbiology Letters (2007), 275(1), 38-45

Dermatomycoses caused by Microsporum canis are frequent in domestic animals and easily transmissible to humans. Several proteases secreted by this fungus were identified as potential virulence factors ... [more ▼]

Dermatomycoses caused by Microsporum canis are frequent in domestic animals and easily transmissible to humans. Several proteases secreted by this fungus were identified as potential virulence factors, but the construction of deficient strains is required to investigate their role in the pathogenesis of the disease. Using target genes encoding two of these proteases, a first evaluation of the utility of RNA-mediated silencing as a reverse genetic tool in dermatophytes was carried out. SUB3 and DPPIV, respectively coding for a subtilisin and a dipeptidyl peptidase, were both down-regulated, by means of two plasmid constructs designed to express an RNA hairpin that corresponds to part of their respective sequence. The degree of attenuation was evaluated by enzymatic assay of the transformants culture supernatants, and by real-time reverse transcriptase-polymerase chain reaction. Enzymatic activities and expression levels varied from less than 5% to 100% of that of control transformants obtained with plasmid without hairpin inserts. Inhibition was globally more efficient for SUB3 than for DPPIV. These results show that RNA silencing can be used for functional genomics in M. canis, and particularly to circumvent the limits and technical difficulties of conventional disruption methods. [less ▲]

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See detailFasciola hepatica: An assessment of the vectorial capacity of Radix labiata and R. balthica commonly found in Belgium
Caron, Yannick ULg; Lasri, Saadia; Losson, Bertrand ULg

Conference (2007, August)

A previous study in Belgium revealed that genetic material of Fasciola sp. was present in four local snail species: Galba truncatula, Radix peregra, Radix ovata and Lymnaea stagnalis. Laboratory cultures ... [more ▼]

A previous study in Belgium revealed that genetic material of Fasciola sp. was present in four local snail species: Galba truncatula, Radix peregra, Radix ovata and Lymnaea stagnalis. Laboratory cultures of these four species were experimentally infected with F. hepatica. The collected metacercariae were fed to rats and the infection in that vertebrate hosts was monitored through several techniques. The mortality rates in the breeding unit was less than 10 % in G. truncatula, R. peregra, and L. stagnalis colonies. Microscopy revealed the presence of larval stages in 78.3 % and 48 % of G. truncatula and R. peregra snails, respectively. These data were confirmed by a PCR that amplifies a parasite specific sequence. R. peregra shed fewer metacercariae and more irregularly than G. truncatula. In R. ovata and L. stagnalis the infection rates were low. Specific DNA was detected in both cases by PCR but no metacercariae were shed. The metacercariae shed by R. peregra were as infective to rats as those from G. truncatula. The PCR technique was more sensitive than microscopic examination. This study demonstrated that R. peregra may act as an accidental intermediate host for F. hepatica in Belgium. [less ▲]

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