Search results for " Helminth"
showing 10 items of 100 documents
Identifying and validating the presence of guanine-quadruplexes (G4) within the blood fluke parasite schistosoma mansoni
2021
Schistosomiasis is a neglected tropical disease that currently affects over 250 million individuals worldwide. In the absence of an immunoprophylactic vaccine and the recognition that mono-chemotherapeutic control of schistosomiasis by praziquantel has limitations, new strategies for managing disease burden are urgently needed. A better understanding of schistosome biology could identify previously undocumented areas suitable for the development of novel interventions. Here, for the first time, we detail the presence of G-quadruplexes (G4) and putative quadruplex forming sequences (PQS) within the Schistosoma mansoni genome. We find that G4 are present in both intragenic and intergenic regi…
Characterisation of fascioliasis lymnaeid intermediate hosts from Chile by DNA sequencing, with emphasis on Lymnaea viator and Galba truncatula.
2011
In South America, Fasciola hepatica infection poses serious health problems in both humans and livestock. In Chile, the medical impact appears yearly stable and mainly concentrated in central regions, where the veterinary problem is highlighted by higher animal prevalences. Studies were undertaken by rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of the lymnaeids, their geographical distribution and fascioliasis transmission capacity in Chile, by comparison with other American countries and continents. Results change the lymnaeid scenario known so far. The lymnaeid fauna of mainland Chile shows to be poor, including only two authochthonous species, Lymnaea via…
MM3-ELISA evaluation of coproantigen release and serum antibody production in sheep experimentally infected with Fasciola hepatica and F. gigantica.
2008
During an experimental infection of sheep with Fasciola hepatica or F. gigantica, MM3-SERO and MM3-COPRO ELISA tests were applied to compare the kinetics of antibody production and coproantigen release between the 2nd and 32nd week post-infection (wpi). The Kato-Katz technique was used to measure the kinetics of egg shedding by both Fasciola species (eggs per gram of feces, epg). The kinetics of IgG antibodies for all sheep infected with F. hepatica and F. gigantica followed a similar pattern. Optical density (OD) increased rapidly between the 4th until the 12th wpi, when the highest values were reached and then decreased slowly until the 32nd wpi. Coproantigen levels increased above the cu…
Ecological, morphological and genetic characterization of sympatric Haemonchus spp. parasites of domestic ruminants in Mauritania
1995
SUMMARYThe 4 species of ruminants (dromedary, zebu cattle, sheep and goat) in arid areas of Mauritania harboured Haemonchus spp. as the most frequent internal parasite. This was a rare situation where the 3 putative species, H. longistipes (dromedary), H. placet (zebu cattle) and H. contortus (sheep and goat) occurred sympatrically. The study was undertaken on hosts slaughtered at the Nouakchott abattoir, on the basis of monthly collection of worms. The environment was very unfavourable to H. placei and unfavourable to H. contortus, as intensity of infection remained low throughout the year, whereas infection in the dromedary was 10 to 20-fold higher. The survival strategies during the long…
Echinostomes: genomics and proteomics
2008
Echinostomes are excellent models to study host-parasite interactions in intestinal helminthiases. In this chapter, data available from genomic and proteomic studies are analyzed in detail to indicate advantages and pitfalls in the research using these organisms. The lack of a genome sequence project and the low number of sequences deposited in the databases not only affect the genomic studies but also debilitate proteomic findings since in most cases, although good spectrometric data can be obtained, the available database often fail to identify the protein from the peptides obtained.
Host manipulation of a freshwater crustacean (Gammarus roeseli) by an acanthocephalan parasite (Polymorphus minutus) in a biological invasion context.
2006
8 pages; International audience; Several gammarid species serve as intermediate hosts for the acanthocephalan parasite Polymorphus minutus. This parasite influences gammarid behaviour in order to favour transmission to its ultimate host, generally a bird. We investigated this host manipulation in Gammarus roeseli, a gammarid species introduced in France 150 years ago which now coexists with several exotic species from different origins. In the field, vertical distribution of G. roeseli revealed a higher proportion of infected individuals close to the water's surface and the size distribution of infected gammarids revealed predation pressure on infected individuals. However, under laboratory…
Molecular and Morphological Differentiation of Two Similar Species of Accacoeliidae (Digenea):Accacladocoelium macrocotyleandA. nigroflavumfrom Sunfi…
2014
In a study of 106 sunfish, Mola mola (L.), from Mediterranean waters, 2,731 worms, belonging to 2 congeneric species of accacoeliids, Accacladocoelium macrocotyle (Diesing, 1858) Robinson, 1934 and Accacladocoelium nigroflavum (Rudolphi, 1819) Robinson, 1934 , were collected from the digestive system. It is often difficult to differentiate between these 2 species as they are sympatric and very similar; in fact, according to previous descriptions, the extent of the vitellarium is the only interspecific difference, described as extending posteriorly to the ovary in A. macrocotyle and as anterior to the anterior testis in A. nigroflavum. However, this diagnostic trait is not always valid; more…
Interrelationships of the Haploporinae (Digenea: Haploporidae): A molecular test of the taxonomic framework based on morphology
2009
The taxonomic framework of the Haploporidae is evaluated and the relationships within the Haploporinae are assessed for the first time at the generic level using molecular data. Partial 28S and complete ITS2 rDNA sequences from representatives of six of the nine recognised genera within the Haploporinae were analysed together with published sequences representing members of two haploporid subfamilies and of the closely related family Atractotrematidae. Molecular analyses revealed: (i) a close relationship between the Atractotrematidae and the Haploporidae; (ii) strong support for the monophyly of the Haploporinae, Dicrogaster and Saccocoelium, and the position of Ragaia within the Haplopori…
Anaphylaxis caused by helminths: review of the literature.
2012
BACKGROUND: Anaphylaxis is a severe, life-threatening, generalized or systemic hypersensitivity reaction. In many individuals with anaphylaxis a pivotal role is played by IgE and the high-affinity IgE receptor on mast cells or basophils. Less commonly, it is triggered through other immunologic mechanisms, or through nonimmunologic mechanisms. The human immune response to helminth infections is associated with elevated levels of IgE, tissue eosinophilia and mastocytosis, and the presence of CD4+ T cells that preferentially produce IL-4, IL-5, and IL-13. Individuals exposed to helminth infections may have allergic inflammatory responses to parasites and parasite antigens. AIM: To summarize th…
Toxocara canis infection induces antigen-specific IL-10 and IFNγ production in pregnant dogs and their puppies
2005
Toxocara canis (T. canis) is originally a parasite of canine bitches and their pups. The pathogenicity of T. canis infection is enhanced during pregnancy and puppyhood. The aim of this study was to investigate if modification of IFNgamma and IL-10 secretion occurs during infection in pregnant dogs and puppies. Analysis of cytokines secreted could let us hypothesize a role for IL-10 and/or IFNgamma in T. canis infection. We tested T. canis-specific production of IFNgamma and IL-10 by lymphocytes of pregnant dogs and their puppies after in vitro re-exposure to purified excretory/secretory antigen (ESAg) from T. canis. Blood mononuclear cells (BMC) isolated from pregnant dogs and their puppies…