References of "Losson, Bertrand"
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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 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), 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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See detailReconstructed interfollicular feline epidermis as a model for Microsporum canis dermatophytosis
Tabart, Jérémy; Baldo, Aline ULg; Vermout, Sandy et al

in Journal of Medical Microbiology (2007), 56(7), 971-975

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis. The complexity of mechanisms involved in dermatophytic infections makes relevant in vivo ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis. The complexity of mechanisms involved in dermatophytic infections makes relevant in vivo studies particularly difficult to perform. The aim of this study was to develop a new in vitro model of M. canis dermatophytosis using feline fetal keratinocytes in reconstructed interfollicular epidermis, and to investigate its relevance in studying the host-pathogen relationship. Histological analysis of reconstructed interfollicular feline epidermis (RFE) revealed a fully differentiated epidermis. A proliferation assay showed replicating cells only in the basal layer, indicating that RFE is a well-stratified living tissue, leading to the formation of a horny layer. Histopathological analysis of RFE infected by M. canis arthroconidia revealed that the fungus invades the stratum corneum and produces SUB3, a keratinase implicated in the infectious process. In view of these results, an M. canis dermatophytosis model on RFE seems to be a useful tool to investigate mechanisms involved in natural M. canis feline infections. [less ▲]

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See detailEchinococcus multilocularis and Toxocara canis in urban red foxes (Vulpes vulpes) in Brussels, Belgium
Brochier, B.; De Blander, H.; Hanosset, R. et al

in Preventive Veterinary Medicine (2007), 80(1), 65-73

During the last decades, European red foxes (Vulpes vulpes) have been implicated in the transmission of several viral or parasitic pathogenic agents to domestic animals and humans. In urban areas, risks ... [more ▼]

During the last decades, European red foxes (Vulpes vulpes) have been implicated in the transmission of several viral or parasitic pathogenic agents to domestic animals and humans. In urban areas, risks of zoonoses transmission are likely to increase as a result of a higher rate of intra and inter-species contacts. Foxes occur on 35% of the Brussels-Capital Region area and local densities reach up to 4 family groups per square kilometre. According to the directive 2003/99/ECC, a first survey for the presence in foxes of Echinococcus multilocularis and Toxocara canis was conducted in Brussels from 2001 to 2004. None of 160 foxes were found to be infected with E. multilocularis and 24 of 134 foxes were found to be infected with T canis. Considering numbers of examined foxes, the sensitivity and the specificity of tests used for diagnosis, the 95% credibility intervals for the true prevalence of E. multilocularis and T canis were estimated in a Bayesian framework to be 0 to 1.87% (median value of 0%) and 12.7 to 26% (median value of 18.7%), respectively. For T canis, a significantly higher risk to be a carrier occurs in cubs and a significantly lower risk in adults. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailLes mécanismes d'adhérence des champignons responsables de mycoses superficielles
Baldo, Aline ULg; Mathy, Anne ULg; Vermout, S. et al

in Annales de Médecine Vétérinaire (2007), 151

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See detailBovine babesiosis in Belgium: preliminary results of a postal survey of veterinarians in 2006
Saegerman, Claude ULg; Claerebout, E.; Kalume, M. et al

in Rencontres autour des Recherches sur les Ruminants (2007), 14

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See detailDescription clinique des cas de FCO survenus au Nord de l'Europe durant l'été et l'automne 2006
Guyot, Hugues ULg; Mauroy, Axel ULg; Thiry, Etienne ULg et al

in Bulletin des Groupements Techniques Vétérinaires (2007), 39(avril), 89-96

La fièvre catarrhale ovine (FCO) a été identifiée au Nord de l’Europe <br />le 14 août 2006. L’Allemagne, la Belgique, les Pays-Bas et, dans une <br />moindre mesure, le Grand-Duché de Luxembourg et la ... [more ▼]

La fièvre catarrhale ovine (FCO) a été identifiée au Nord de l’Europe <br />le 14 août 2006. L’Allemagne, la Belgique, les Pays-Bas et, dans une <br />moindre mesure, le Grand-Duché de Luxembourg et la France ont été <br />affectés. Le sérotype 8 du virus de la FCO (exotique) a rapidement été <br />identifié ainsi qu’un vecteur, Culicoides dewulfi, une espèce indigène du <br />Nord de l’Europe. La maladie s’est rapidement développée et au 1er <br />février 2007, on recensait 2137 foyers de FCO, toutes espèces de <br />ruminants confondues. Globalement, la maladie a affecté davantage les <br />bovins (54 %) que les ovins (46 %). Les signes cliniques les plus <br />fréquemment observés chez les bovins étaient des lésions sur le museau <br />et la cavité buccale (ulcérations/croûtes), de la salivation et des boiteries <br />chez des animaux adultes. La morbidité et la mortalité animales étaient <br />respectivement de maximum 5 % et 1 %. Les principaux signes cliniques <br />rencontrés chez le mouton étaient également des lésions sur le museau <br />et la cavité buccale (ulcérations/croûtes), de l’amaigrissement et des <br />boiteries. La morbidité et la mortalité animales étaient respectivement <br />de maximum 12 % et 6 %. Les signes cliniques n’étant pas <br />pathognomoniques et le diagnostic différentiel relativement vaste, seul <br />un examen de laboratoire permet d’établir un diagnostic de certitude. [less ▲]

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See detailBiting Midges Overwintering In Belgium
Losson, Bertrand ULg; Mignon, Bernard ULg; Paternostre, Julien ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2007), 160(13), 451-452

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See detailReconstructed interfollicular feline epidermis as a model for the screening of drugs against Microsporum canis
Mignon, Bernard ULg; Tabart, J.; Baldo, Aline ULg et al

in Veterinary Dermatology (2007), 18

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See detailDiagnostic et surveillance épidémiologique de Neospora caninum
Ghalmi, F.; China, B.; Losson, Bertrand ULg

in Annales de Médecine Vétérinaire (2007), 151

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See detailFièvre Catarrhale Ovine chez les ruminants. Description clinique des cas vécus dans le Nord de l’Europe durant l’été-automne 2006
Guyot, Hugues ULg; Mauroy, Axel ULg; Thiry, Etienne ULg et al

in Bulletin des GTV (2007)

La fièvre catarrhale ovine (FCO) a été identifiée au Nord de l’Europe le 14 août 2006. L’Allemagne, la Belgique, les Pays-Bas et, dans une moindre mesure, le Grand-Duché de Luxembourg et la France ont été ... [more ▼]

La fièvre catarrhale ovine (FCO) a été identifiée au Nord de l’Europe le 14 août 2006. L’Allemagne, la Belgique, les Pays-Bas et, dans une moindre mesure, le Grand-Duché de Luxembourg et la France ont été affectés. Le sérotype 8 du virus de la FCO (exotique) a rapidement été identifié ainsi qu’un vecteur, Culicoides dewulfi, une espèce indigène du Nord de l’Europe. La maladie s’est rapidement développée et au 1er février 2007, on recensait 2137 foyers de FCO, toutes espèces de ruminants confondues. Globalement, la maladie a affecté davantage les bovins (54 %) que les ovins (46 %). Les signes cliniques le plus fréquemment observés chez les bovins étaient des lésions sur le museau et la cavité buccale (ulcérations/croûtes), de la salivation et des boiteries chez des animaux adultes. La morbidité et la mortalité animales étaient respectivement de maximum 5 % et 1 %. Les principaux signes cliniques rencontrés chez le mouton étaient également des lésions sur le museau et la cavité buccale (ulcérations/croûtes), de l’amaigrissement et des boiteries. La morbidité et la mortalité animales étaient respectivement de maximum 12 % et 6 %. Les signes cliniques n’étant pas pathognomoniques et le diagnostic différentiel relativement vaste, seul un examen de laboratoire permet de poser un diagnostic de certitude. [less ▲]

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See detailSpatial spreading of Echinococcus multilocularis in Red foxes (Vulpes vulpes) across nation borders in Western Europe
Vervaeke, M.; van der Giessen, J.; Brochier, B. et al

in Preventive Veterinary Medicine (2006), 76(3-4), 137-150

The occurrence of the fox tapeworm Echinococcus multilocularis in Red foxes was studied in Belgium and a neighbouring region in The Netherlands. A total number of 1202 foxes were analysed (1018 in Belgium ... [more ▼]

The occurrence of the fox tapeworm Echinococcus multilocularis in Red foxes was studied in Belgium and a neighbouring region in The Netherlands. A total number of 1202 foxes were analysed (1018 in Belgium and 184 in The Netherlands) of which 179 were infected with E. multilocularis (164 in Belgium and 15 in The Netherlands). Further, the spatial distribution of infection among sampled foxes was analysed with an ellipsoidal gradient, demonstrating a decreasing prevalence in northwestern direction. Using this gradient, we showed that the spatial patterns of infection in Belgium and the neighbouring region in The Netherlands correspond, indicating a continuous distribution of E. multilocularis across the nation borders. Part of the Belgian data allowed investigating temporal changes in the spatial distribution of E. multilocularis. This revealed a northwestern spread of E. multilocularis. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailEcological characteristic's of small farmland ponds: Associations with land use practices at multiple spatial scales
Declerck, Steven; De Bie, Tom; Ercken, Dirk et al

in Biological Conservation (2006), 131(4), 523-532

Despite their restricted surface area, small farmland ponds often have a high conservation value because they contribute significantly to regional biodiversity and contain rare or unique species. For this ... [more ▼]

Despite their restricted surface area, small farmland ponds often have a high conservation value because they contribute significantly to regional biodiversity and contain rare or unique species. For this reason, the creation of new ponds has become a widely applied practice in many countries. information on the effects of land use on farmland ponds is very scarce. Farmland ponds differ from larger ponds, lakes and livers in many aspects and can therefore be expected to be affected by land use via other mechanisms operating at different spatial scales. We here present a study on 126 ponds distributed over the entire territory of Belgium (surface area: 30.500 km(2)). We assessed variables related to turbidity state and vegetation complexity and related them to land use variables assessed at several spatial scales ranging from the pond edge up to 32 km(2) circular areas. According to redundancy analysis, trampling by cattle and percentage cover of nearby crop land were positively associated with turbid state related variables. Conversely, ponds with high coverage by forest in the immediate neighbourhood tended to be more associated with the clear water state. Multiple regression analysis demonstrated a negative effect of trampling and coverage by crop land on vegetation complexity. Effects of crop lands and forest were strongest at the local scale (< 200 m radius) which indicates that adverse external influences can most efficiently be mitigated at a small scale. Based on these results we suggest several recommendations for pond construction and conservation. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailIn vitro entomopathogenic activity of Beauveria bassiana against Psoroptes spp. (Acari : Psoroptidae)
Lekimme, Mireille ULg; Mignon, Bernard ULg; Tombeux, S. et al

in Veterinary Parasitology (2006), 139(1-3), 196-202

An indigenous strain (IHEM 18747) of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycetes) was evaluated for its in vitro entomopathogenic activity against the parasitic mite Psoroptes ovis Hering ... [more ▼]

An indigenous strain (IHEM 18747) of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycetes) was evaluated for its in vitro entomopathogenic activity against the parasitic mite Psoroptes ovis Hering (Acari: Psoroptidae) from rabbits. The following aspects were evaluated: (1) effects of conidial concentration on the viability of adult females; (2) influence of the infection on the fertility, and on the hatchability of eggs; (3) and transmission of infection between mites, and from contaminated surface. Adult females immersed into increasing concentrations of conidia (10(4)-10(9) conidia ml(-1)) showed a dose-related susceptibility. At the highest concentration of conidia, LT50 was 1.6 days while LT50 of the controls reached 5.8 days. The fungus was able to sporulate on the body surface and 100% of the mites were covered with mycelium after immersion in solutions containing 10(7)-10(9) conidia ml(-1). One hundred percent of healthy mites exposed to infected cadavers or surfaces acquired the infection (LT50 reached 1.9 and 1.73 days, respectively, versus 6.1 and 5.1 days in controls, respectively). Egg laying was not reduced by the fungal infection but both the hatchability of the eggs and the life span of the emerging larvae were significantly reduced. Eggs directly infected with the fungus did not show reduced hatchability but the life span of the larvae was shortened. It is concluded that B. bassiana has a high entomopathogenic activity against Psoroptes spp. The in vivo use of this biocontrol agent against Psoroptes spp. in rabbit, sheep and cattle deserves further attention. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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