نتایج جستجو برای: intermediate host

تعداد نتایج: 339629  

Journal: :Evolution; international journal of organic evolution 2010
Nathalie Franceschi Stéphane Cornet Loic Bollache François-Xavier Dechaume-Moncharmont Alexandre Bauer Sébastien Motreuil Thierry Rigaud

Many trophically transmitted parasites manipulate their intermediate host phenotype, resulting in higher transmission to the final host. However, it is not known if manipulation is a fixed adaptation of the parasite or a dynamic process upon which selection still acts. In particular, local adaptation has never been tested in manipulating parasites. In this study, using experimental infections b...

Journal: :Parasitology 2017
C Lagrue R Rinnevalli R Poulin

A number of parasites with complex life cycles can abbreviate their life cycles to increase the likelihood of reproducing. For example, some trematodes can facultatively skip the definitive host and produce viable eggs while still inside their intermediate host. The resulting shorter life cycle is clearly advantageous when transmission probabilities to the definitive hosts are low. Coitocaecum ...

Journal: :Journal of helminthology 2005
F Lefebvre R Poulin

Abbreviations of the complex life cycle of trematodes, from three to two hosts, have occurred repeatedly and independently among trematode lineages. This is usually facultative and achieved via progenesis: following encystment in the second intermediate host, the metacercaria develops precociously into an egg-producing adult, bypassing the need to reach a definitive host. Given that it provides...

Journal: :Proceedings. Biological sciences 2008
Otto Seppälä E Tellervo Valtonen Daniel P Benesh

Trophically transmitted parasites often alter their intermediate host's phenotype, thereby predisposing the hosts to increased predation. This is generally considered a parasite strategy evolved to enhance transmission to the next hosts. However, the adaptive value of host manipulation is not clear as it may be associated with costs, such as increased susceptibility to predators that are unsuit...

Journal: :The Journal of parasitology 2012
Kristin K Herrmann Robert Poulin

Numerous parasite species have evolved complex life cycles with multiple, subsequent hosts. In trematodes, each transmission event in multi-host life cycles selects for various adaptations, one of which is facultative life cycle abbreviation. This typically occurs through progenesis, i.e., precocious maturity and reproduction via self-fertilization within the second intermediate host. Progenesi...

Journal: :Folia parasitologica 2003
Bahram S Dezfuli Barbara J Maynard Todd A Wellnitz

The acanthocephalan parasite Pomphorhynchus laevis (Müller, 1776) uses freshwater amphipods as its intermediate host. In order to complete the life cycle, the infected amphipod must be consumed by a fish, where the acanthocephalan will mature and reproduce. Parasite transmission, and therefore fitness, could be enhanced if infected amphipods fail to detect or avoid predatory fish. We compared t...

Journal: :Parasitology 2008
C Lagrue R Poulin

Parasites with complex life cycles have developed numerous and very diverse adaptations to increase the likelihood of completing this cycle. For example, some parasites can abbreviate their life cycles by skipping the definitive host and reproducing inside their intermediate host. The resulting shorter life cycle is clearly advantageous when definitive hosts are absent or rare. In species where...

Journal: :Molecular phylogenetics and evolution 1999
O J Holmdahl D A Morrison J T Ellis L T Huong

We present an evolutionary analysis of 13 species of Sarcocystis, including 4 newly sequenced species with ruminants as their intermediate host, based on complete small subunit rDNA sequences. Those species with ruminants as their intermediate host form a well-supported clade, and there are at least two major clades within this group, one containing those species forming microcysts and with dog...

Journal: :PLoS Neglected Tropical Diseases 2008
David R. J. Pleydell Yu Rong Yang F. Mark Danson Francis Raoul Philip S. Craig Donald P. McManus Dominique A. Vuitton Qian Wang Patrick Giraudoux

BACKGROUND Alveolar echinococcosis (AE) presents a serious public health challenge within China. Mass screening ultrasound surveys can detect pre-symptomatic AE, but targeting areas identified from hospital records is inefficient regarding AE. Prediction of undetected or emerging hotspots would increase detection rates. Voles and lemmings of the subfamily Arvicolinae are important intermediate ...

Journal: :Journal of evolutionary biology 2007
C Lagrue R Poulin

The complex life cycles of parasites are thought to have evolved from simple one-host cycles by incorporating new hosts. Nevertheless, complex developmental routes present parasites with a sequence of highly unlikely transmission events in order to complete their life cycles. Some trematodes like Coitocaecum parvum use facultative life cycle abbreviation to counter the odds of trophic transmiss...

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