Search results for "Parasite"
showing 10 items of 827 documents
Microsporidian disease of the invasive amphipod Dikerogammarus villosus and the potential for its transfer to local invertebrate fauna.
2012
12 pages; International audience; Invasive species may introduce novel pathogens to a colonised area. Most of the time emerging pathogens are detected a posteriori, but recognition of a priori emergence of an invasive disease by host shift may be useful for predictive purposes. Here, we studied if the microsporidian parasite Cucumispora dikerogammari infecting the invasive Ponto-Caspian amphipod Dikerogammarus villosus, has the potential to become an emergent disease in invaded rivers in Western and Central Europe. We first showed that this parasite decreases the survival of D. villosus in the later stages of infection development. However, the host reproduces earlier in response to the inf…
Multidimensionality in host manipulation mimicked by serotonin injection.
2014
Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. ‘Multidimensionality’ in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in ‘host manipulation’ between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host–parasite association the effect size of the difference between infected and uninfect…
Larval size in acanthocephalan parasites : Influence of intraspecific competition and effects on intermediate host behavioural changes
2012
Abstract Background Parasites often face a trade-off between exploitation of host resources and transmission probabilities to the next host. In helminths, larval growth, a major component of adult parasite fitness, is linked to exploitation of intermediate host resources and is influenced by the presence of co-infecting conspecifics. In manipulative parasites, larval growth strategy could also interact with their ability to alter intermediate host phenotype and influence parasite transmission. Methods We used experimental infections of Gammarus pulex by Pomphorhynchus laevis (Acanthocephala), to investigate larval size effects on host behavioural manipulation among different parasite sibshi…
Gammarids and acanthocephalans, a multi-(cryptic) hosts and multi-parasites system?
2022
Multi-host parasites can exploit various host species that differ in abundance and susceptibility to infection, which will contribute unequally to their transmission and fitness. "Key hosts" are those contributing significantly more to the completion of the life cycle of such parasites. Three non-exclusive criteria may be used to identify a key host: its high abundance, its high exposure/susceptibility to infection, and the large number of infectious stages produced per infected individual. Many parasites with complex life cycles have evolved the ability to manipulate several traits of their intermediate hosts' phenotype, including behavior, thereby increasing the likelihood of transmission…
Trophic relationships between the parasitic plant species phelipanche ramosa (L.) and different hosts depending on host phenological stage and host g…
2016
Prod 2018-285c INRA AGROSUP GESTAD SPE CT3 SPE CT1 EJ2 EA; International audience; Phelipanche ramosa (L.) Pomel (branched broomrape) is a holoparasitic plant that reproduces on crops and also on weeds, which contributes to increase the parasite seed bank in fields. This parasite extracts all its nutrients at the host’s expense so that host–parasite trophic relationships are crucial to determine host and parasite growth. This study quantified the intensity with which P. ramosa draws assimilates from its host and analyzed whether it varied with host species, host phenological stage and host growth rate. A greenhouse experiment was conducted on three host species: the crop species Brassica na…
Modélisation des effets des systèmes de culture sur la dynamique de la plante parasite orobanche rameuse en interaction avec les adventices
2019
Reducing pesticide use is a major challenge in agriculture and involves developing more sustainable methods that rely on non-chemical cropping techniques and biological regulations according to agroecological principles. Branched broomrape (Phelipanche ramosa (L.) Pomel) is a root parasitic plant which infects crops and causes dramatic yield losses worldwide. Managing broomrape is complex because it requires combining several cropping techniques whithin a global weed management strategy because broomrape is also able to infect non-parasitic weeds. The aim of this thesis was to stynthetize knowledge on branched broomrape dynamics in agroecosystems and to aggregate it within a mechanistic mod…
Modalités fonctionnelles et évolutives des parasitoses développées par les crabes Pinnotheridae aux dépens des échinides fouisseurs
2010
Ce travail s’est intéressé aux liens existant entre la stratégie d’exploitation développée par un crustacé ectoparasite et son comportement reproductif. Le crabe Pinnotheridae Dissodactylusprimitivus exploite deux espèces Spatangidae vivant dans la Mer des Caraïbes, Meomaventricosa et Plagiobrissus grandis. Des approches comportementales, démographiques etgénétiques ont été adoptées afin de mettre en lumière le fonctionnement et la biologie de cettesymbiose. Par son comportement alimentaire, le crabe occasionne des lésions tégumentairessur ses hôtes. Celles-ci affectent la fitness de M. ventricosa, au travers de son développementgonadique. Dissodactylus primitivus exploite ses deux espèces …
Persistent establishment of a tropical disease in Europe: the preadaptation of schistosomes to overwinter
2019
International audience; Background: Global changes promote the spread of infectious diseases worldwide. In this context, tropical uro-genital schistosomiasis is now permanently established in Corsica since its first emergence in 2013. The local persistence of the tropical pathogens (schistosomes) responsible for urogenital schistosomiasis at such latitudes might be explained by (i) the presence of its intermediate host, the snail Bulinus truncatus, (ii) the recurrent local reseeding of schistosomes by their vertebrate hosts (either human or animal) every summer, and/or (iii) the maintenance and survival of schistosomes within their snail hosts over winter.Methods: In this study we conducted…
Modélisation des effets des systèmes de culture sur la dynamique de la plante parasite orobanche rameuse en interaction avec les adventices
2019
Reducing pesticide use is a major challenge in agriculture and involves developing more sustainable methods that rely on non-chemical cropping techniques and biological regulations according to agroecological principles. Branched broomrape (Phelipanche ramosa (L.) Pomel) is a root parasitic plant which infects crops and causes dramatic yield losses worldwide. Managing broomrape is complex because it requires combining several cropping techniques whithin a global weed management strategy because broomrape is also able to infect non-parasitic weeds. The aim of this thesis was to stynthetize knowledge on branched broomrape dynamics in agroecosystems and to aggregate it within a mechanistic mod…
Etude de l’infection la plante parasite Rhamphicarpa fistulosa en riziculture au Togo
2013
Rhamphicarpa fistulosa (Hochst.) Benth. is an annual facultative root-parasitic weed found in lowlands and floodplains in tropical Africa. It has been reported as the major constraint to rice cultivation in the savannah region of Togo. A survey was conducted in 2012 to access its distribution and to collect information on farmers' knowledge of its control. Rhamphicarpa fistulosa was found in 80% of the 33 visited lowlands. The period of abundance is in August-September when the highest infection (90%) was found on sandy and clay soils. When the parasite was present, 94 other weeds belonging to 24 botanical families were recorded. As management method, farmers use weeding and chemical fertil…