Attaques massives de simulies et mort brutale

peer reviewe

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

Perspectives de vaccination anti-dermatophytique chez les carnivores domestiques

peer reviewe

Crassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean

On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage

Epidemiology of multilocular echinococcosis in Europe

In Europe, the life cycle of Echinococcus multilocularis is based for the most part on a sylvatic cycle, with wild carnivores (mainly the red fox, Vulpes vulpes) as definitive hosts and several small mammals (mainly Arvicolidae and Cricetidae) as intermediate hosts. Domestic dogs and cats may be involved in a synanthropic cycle. Evidence suggests that, in most of the endemic regions, the sylvatic cycle of E. multilocularis is the predominant source of infection for humans and other aberrant hosts. The geographical distribution of this parasitosis seems to be much wider than initially thought two or three decades ago. Transmission dynamics are influenced by many factors which are described here. For instance, the marked increase in fox populations in periurban and urban areas is an issue which must be addressed by local and/or national authorities.Echinococcus multilocularis utilise essentiellement, en Europe, un cycle sylvatique reposant sur des carnivores sauvages (surtout le renard roux, Vulpes vulpes) qui jouent le rôle d'hôtes définitifs et sur des petits mammifères (essentiellement des Arvicolidae et Cricetidae) qui sont les hôtes intermédiaires. Le chien et le chat peuvent être impliqués dans un cycle synanthropique. De nombreuses études suggèrent que, dans la plupart des régions d'endémie, le cycle sylvatique représente la principale source de contamination pour l'homme et les autres hôtes aberrants. La distribution géographique de cette parasitose semble beaucoup plus étendue que celle initialement décrite il y a deux ou trois décennies. La dynamique de transmission est influencée par de nombreux facteurs qui sont décrits dans la présente communication. En particulier, la forte augmentation des populations vulpines en régions périurbaine et urbaine doit retenir l'attention des pouvoirs publics

RNA silencing in the dermatophyte Microsporum canis

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 method

RNA silencing in the dermatophyte Microsporum canis

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 method