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

Malacological aspects of the lifecycle of Fasciola hepatica in Belgium and Ecuador

La fasciolose est une maladie zoonotique touchant principalement les ruminants et due à deux espèces parasitaires du genre Fasciola. Si Fasciola gigantica est une espèce tropicale, la distribution géographique de F. hepatica est beaucoup plus large. Fasciola hepatica est responsable de pertes économiques conséquentes comme par exemple la réduction de la production laitière ou la saisie du foie des ruminants à l’abattoir. Le cycle de vie de ce plathelminthe nécessite un hôte intermédiaire, un mollusque gastéropode de la famille des Lymnaeidae. En Europe tempérée, Galba truncatula est le principal hôte intermédiaire de F. hepatica. Un vaste projet en réseau (MANSCAPE) a montré, en réalisant des prélèvements dans plus de 125 mares, que d’autres mollusques lymnaeidés (appartenant au genre Radix) pouvaient intervenir en Belgique dans le cycle du parasite comme hôte intermédiaire accessoire ou alternatif. Des infestations expérimentales de mollusques et de rats ont permis de mettre en évidence plus précisément quelques-unes de ces espèces (Radix balthica, R. labiata). Le complexe d’espèces « R. peregra » semble ainsi contenir plusieurs candidats potentiels. Plusieurs techniques existent pour mettre en évidence le parasite dans le mollusque : des techniques microscopiques et des techniques faisant appel à la biologie moléculaire. Une technique de biologie moléculaire (PCR Multiplex) très sensible (100 pg d’ADN du parasite restent détectables) et spécifique a été mise au point. Cette technique a ensuite été utilisée de manière qualitative et quantitative pour établir dans quelle mesure les espèces pouvant faire office d’hôte intermédiaire alternatif en Belgique étaient, en effet, infestées. C’est ainsi que, dans le cadre du projet PONDSCAPE, il a été montré que G. truncatula était infesté à hauteur de 1,31 % (30/2747) et que R. balthica pouvait héberger le parasite selon une prévalence de 0,16 % (7/4629). La technique a ensuite été utilisée en Equateur pour apporter de la même façon des éclaircissements sur les espèces impliquées dans le cycle. Galba schirazensis, une espèce invasive en Amérique du Sud a été identifiée comme pouvant héberger une partie du cycle de F. hepatica puisque 8,15 % (86/1055) des mollusques prélevés contenaient de l’ADN du parasite et 2,46 % (26/1055) des rédies vivantes. Ces études montrent que Radix balthica pourrait avoir un impact sur l’épidémiologie de F. hepatica en Belgique et que le rôle de G. schirazensis en Equateur mérite d’être éclairci. Ceci sera discuté lors de ce travail et notamment en termes d’adaptation et de coévolution.Fasciolosis is a zoonotic disease of ruminants and other herbivorous due to two parasite species of the genus Fasciola. If Fasciola gigantica is a tropical species, F. hepatica has a much wider geographic distribution. Fasciola hepatica is responsible for important economic losses such as a marked reduction of milk yield and liver condemnation at the slaughterhouse. The life cycle of this platyhelminth involves an intermediate host, a gastropod mollusc belonging to the Lymnaeidae family. In temperate Europe, Galba truncatula acts as the main intermediate host of F. hepatica. A wide network project called MANSCAPE allowed the implementation of a sampling campaign conducted in more than 125 ponds throughout Belgium which revealed that other lymnaeid snails (belonging to the genus Radix) could act as secondary or alternative intermediate hosts. Some experimental infections of snails and rats permited to study the host-parasite relationships in some of these species (Radix balthica, R. labiata). Sibling species very similar to « R. peregra » seem to contain several potential candidates. Several techniques are available to detect the parasite in the snail: they are based either on microscopy or on molecular biology. A very sensitive (100 pg parasite DNA still detectable) and specific technique based on molecular biology (Multiplex PCR) was developed. This technique was used qualitatively and quantitatively to determine the intermediate host species involved in the life cycle of the liver fluke in Belgium. This study was performed in the frame of the PONDSCAPE project and prevalences of 1.31% (30/2747) and 0.16% (7/4629) were recorded for G. truncatula and R. balthica respectively. This technique was then used in Ecuador to bring some information on the intermediate host species involved in the life cycle of F. hepatica. Galba schirazensis, an invasive species in South America, was identified as a lymnaeid that could harbour a part of the life cycle of the parasite as 8.15% (86/1055) of the collected snail contained parasite DNA and 2.46% (26/1055) living larvae. These studies showed that R. balthica could have an impact on the epidemiology of F. hepatica in Belgium and that the role of G. schirazensis in Ecuador needs to be clarified. This will be discussed in this work and specially in term of co-evoultion and adpatation way

Two identification tools applied on Mascarene’s corals genera (Xper2) and species (IKBS)

For future biodiversity studies relying on species identification, environmental officers and researchers will only be left with monographic descriptions and collections in museums. This is why a knowledge base on the zooxanthellate scleractinian corals of the Mascarene Archipelago is being developed. This project offers results for both biologists/taxonomists and students or MPA-teams. Two online computer-based applications permit to identify genera and species. The first identification tool, called Xper², was developed by LIS (Informatic and Systematics Laboratory) in Paris, and is used for identifications to genera. The second tool, named IKBS (Iterative Knowledge Base System), was developed by IREMIA (Institute for Research in Applied Mathematics and Computer Science) in La Réunion, and is used for identifications from families to species. The tools presently work for Astrocoeniidae, Pocilloporidae, Acroporidae (only Acropora + Isopora), Psammocoridae, Siderastreidae (owns Psammocoridae as genera), Fungiidae, Poritidae, Faviidae Faviinae, Faviidae Montastreinae, Mussidae. We plan to start a new phase to add the last families, fully translate the web site in English and extend the Xper² identification to all the western Indian Ocean genera

Calogero-Sutherland Approach to Defect Blocks

Extended objects such as line or surface operators, interfaces or boundaries play an important role in conformal field theory. Here we propose a systematic approach to the relevant conformal blocks which are argued to coincide with the wave functions of an integrable multi-particle Calogero-Sutherland problem. This generalizes a recent observation in 1602.01858 and makes extensive mathematical results from the modern theory of multi-variable hypergeometric functions available for studies of conformal defects. Applications range from several new relations with scalar four-point blocks to a Euclidean inversion formula for defect correlators.Comment: v2: changes for clarit

Cas de gale sarcoptique chez des renards en Belgique

Eight cases of sarcoptic mange in foxes were reported during summer 2014 (n=3) and winter 2015 (n= 5) in Belgium. All animals came from the same restricted forest zones near urbanized areas and some of them were discovered in private gardens (Forest District of Thuin, Hainaut, Belgium). Three of them were found dead, the others were shot for sanitary reasons. At necropsy, all of them presented large areas of alopecia and extensive skin lesions such as hyperkeratosis and suppurative lacerations. Animals presented poor body condition and some of them were severely emaciated (absence of visceral fat). Mange has profound influences on population since, if untreated, death follows in four to six months. In the present cases, cutaneous scrapings and histopathological examinations were systematically performed. Numerous parasites were observed in skin scrapings and marked dermo-epidermatitis with several parasites was observed in histopathological sections. These results suggest an outbreak of sarcoptic mange in red foxes in a limited area of the country. This is a first record for the country. Furthermore, investigations on lungs and digestive tracts performed on 3 of these foxes revealed they were also infected by parasites transmissible to pets and/or humans: Angiostrongylus vasorum was observed in the respiratory tract of one fox whereas Toxocara canis, Uncinaria stenocephala, Taenia spp. and Echinococcus multilocularis worms were detected in the digestive tract. In conclusion, urban foxes represent a source of parasites of public health and veterinary importance and foxes surveillance should be strengthened in these areas

Coxiella burnetii, the Agent of Q Fever, Replicates within Trophoblasts and Induces a Unique Transcriptional Response

Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium typically found in myeloid cells. The infection is a source of severe obstetrical complications in humans and cattle and can undergo chronic evolution in a minority of pregnant women. Because C. burnetii is found in the placentas of aborted fetuses, we investigated the possibility that it could infect trophoblasts. Here, we show that C. burnetii infected and replicated in BeWo trophoblasts within phagolysosomes. Using pangenomic microarrays, we found that C. burnetii induced a specific transcriptomic program. This program was associated with the modulation of inflammatory responses that were shared with inflammatory agonists, such as TNF, and more specific responses involving genes related to pregnancy development, including EGR-1 and NDGR1. In addition, C. burnetii stimulated gene networks organized around the IL-6 and IL-13 pathways, which both modulate STAT3. Taken together, these results revealed that trophoblasts represent a protective niche for C. burnetii. The activation program induced by C. burnetii in trophoblasts may allow bacterial replication but seems unable to interfere with the development of normal pregnancy. Such pathophysiologocal processes should require the activation of immune placental cells associated with trophoblasts

Value of ultrasonography as a marker of early response to abatacept in patients with rheumatoid arthritis and an inadequate response to methotrexate: results from the APPRAISE study

Objectives: To study the responsiveness of a combined power Doppler and greyscale ultrasound (PDUS) score for assessing synovitis in biologic-naïve patients with rheumatoid arthritis (RA) starting abatacept plus methotrexate (MTX). Methods: In this open-label, multicentre, single-arm study, patients with RA (MTX inadequate responders) received intravenous abatacept (∼10 mg/kg) plus MTX for 24 weeks. A composite PDUS synovitis score, developed by the Outcome Measures in Rheumatology–European League Against Rheumatism (OMERACT–EULAR)-Ultrasound Task Force, was used to evaluate individual joints. The maximal score of each joint was added into a Global OMERACT–EULAR Synovitis Score (GLOESS) for bilateral metacarpophalangeal joints (MCPs) 2–5 (primary objective). The value of GLOESS containing other joint sets was explored, along with clinical efficacy. Results: Eighty-nine patients completed the 24-week treatment period. The earliest PDUS sign of improvement in synovitis was at week 1 (mean change in GLOESS (MCPs 2–5): −0.7 (95% CIs −1.2 to −0.1)), with continuous improvement to week 24. Early improvement was observed in the component scores (power Doppler signal at week 1, synovial hyperplasia at week 2, joint effusion at week 4). Comparable changes were observed for 22 paired joints and minimal joint subsets. Mean Disease Activity Score 28 (C reactive protein) was significantly reduced from weeks 1 to 24, reaching clinical meaningful improvement (change ≥1.2) at week 8. Conclusions: In this first international prospective study, the composite PDUS score is responsive to abatacept. GLOESS demonstrated the rapid onset of action of abatacept, regardless of the number of joints examined. Ultrasound is an objective tool to monitor patients with RA under treatment. Trial registration number: NCT00767325