Characterization of a new type of neuronal 5-HT G- protein coupled receptor in the cestode nervous system.

Cestodes are platyhelminth parasites with a wide range of hosts that cause neglected diseases. Neurotransmitter signaling is of critical importance for these parasites which lack circulatory, respiratory and digestive systems. For example, serotonin (5-HT) and serotonergic G-protein coupled receptors (5-HT GPCRs) play major roles in cestode motility, development and reproduction. In previous work, we deorphanized a group of 5-HT7 type GPCRs from cestodes. However, little is known about another type of 5-HT GPCR, the 5-HT1 clade, which has been studied in several invertebrate phyla but not in platyhelminthes. Three putative 5-HT GPCRs from Echinococcus canadensis, Mesocestoides vogae (syn. M. corti) and Hymenolepis microstoma were cloned, sequenced and bioinformatically analyzed. Evidence grouped these new sequences within the 5-HT1 clade of GPCRs but differences in highly conserved GPCR motifs were observed. Transcriptomic analysis, heterologous expression and immunolocalization studies were performed to characterize the E. canadensis receptor, called Eca-5-HT1a. Functional heterologous expression studies showed that Eca-5-HT1a is highly specific for serotonin. 5-Methoxytryptamine and α-methylserotonin, both known 5-HT GPCR agonists, give stimulatory responses whereas methysergide, a known 5-HT GPCR ligand, give an antagonist response in Eca-5-HT1a. Mutants obtained by the substitution of key predicted residues resulted in severe impairment of receptor activity, confirming that indeed, these residues have important roles in receptor function. Immunolocalization studies on the protoscolex stage from E. canadensis, showed that Eca-5-HT1a is localized in branched fibers which correspond to the nervous system of the parasite. The patterns of immunoreactive fibers for Eca-5-HT1a and for serotonin were intimately intertwined but not identical, suggesting that they are two separate groups of fibers. These data provide the first functional, pharmacological and localization report of a serotonergic receptor that putatively belongs to the 5-HT1 type of GPCRs in cestodes. The serotonergic GPCR characterized here may represent a new target for antiparasitic intervention.

International consensus on terminology to be used in the field of echinococcoses.

Echinococcoses require the involvement of specialists from nearly all disciplines; standardization of the terminology used in the field is thus crucial. To harmonize echinococcosis terminology on sound scientific and linguistic grounds, the World Association of Echinococcosis launched a Formal Consensus process. Under the coordination of a Steering and Writing Group (SWG), a Consultation and Rating Group (CRG) had the main missions of (1) providing input on the list of terms drafted by the SWG, taking into account the available literature and the participants' experience; and (2) providing independent rating on all debated terms submitted to vote. The mission of the Reading and Review Group (RRG) was to give an opinion about the recommendation paper in terms of readability, acceptability and applicability. The main achievements of this process were: (1) an update of the current nomenclature of Echinococcus spp.; (2) an agreement on three names of diseases due to Echinococcus spp.: Cystic Echinococcosis (CE), Alveolar Echinococcosis (AE) and Neotropical Echinococcosis (NE), and the exclusion of all other names; (3) an agreement on the restricted use of the adjective "hydatid" to refer to the cyst and fluid due to E. granulosus sensu lato; and (4) an agreement on a standardized description of the surgical operations for CE, according to the "Approach, cyst Opening, Resection, and Completeness" (AORC) framework. In addition, 95 "approved" and 60 "rejected" terms were listed. The recommendations provided in this paper will be applicable to scientific publications in English and communication with professionals. They will be used for translation into other languages spoken in endemic countries.

TITLE: Consensus international sur la terminologie à utiliser dans le domaine des échinococcoses. ABSTRACT: Les échinococcoses impliquent l'intervention de spécialistes de presque toutes les disciplines et une standardisation de la terminologie utilisée dans le domaine est donc cruciale. Pour harmoniser la terminologie des échinococcoses sur des bases scientifiques et linguistiques bien étayées, l'Association Mondiale de l'Échinococcose a entrepris un processus de « Consensus Formalisé ¼. Sous la coordination d'un Groupe de Pilotage et de Rédaction (GPR), un Groupe de Consultation et de Classement (GCC) a reçu les missions suivantes : (1) fournir un avis sur une liste de termes établie par le GPR, en prenant en compte les références scientifiques disponibles et l'expérience des participants ; (2) fournir un classement indépendant sur tous les termes débattus et soumis au vote. La mission du Groupe de Lecture et de Revue critique (GLR) était de donner un avis formel sur l'article de recommandations en termes de facilité de lecture, d'acceptabilité et d'applicabilité. Les principales avancées obtenues au terme de ce processus sont les suivantes: (1) une actualisation de la nomenclature actuelle des espèces d'Echinococcus ; (2) un accord sur les noms des trois principales maladies humaines dues aux espèces d'Echinococcus : l'échinococcose kystique (EK), l'échinococcose alvéolaire (EA) et l'échinococcose néotropicale (EN), à l'exclusion de toute autre dénomination ; (3) la restriction de l'usage de l'adjectif « hydatique ¼ au kyste et au liquide/fluide produit par E. granulosus sensu lato ; et (4) une description standardisée des interventions chirurgicales pour l'EK, selon le système AORC (pour « Approche ¼, « Ouverture ¼, « Résection ¼ et « Complétude ¼). De plus, 95 termes « approuvés ¼ et 60 termes « rejetés ¼ ont été listés. Les recommandations données dans cet article seront applicables aux publications scientifiques en anglais et à la communication avec les professionnels. Elles seront utilisées pour la traduction dans les autres langues parlées dans les zones d'endémie.

Evaluation of three PCR assays for the identification of the sheep strain (genotype 1) of Echinococcus granulosus in canid feces and parasite tissues.

The performance of 3 PCR assays for the identification of the G1 sheep genotype of Echinococcus granulosus was evaluated using tissue and canid fecal samples. The "Dinkel" and "Stefanic" primers were the most sensitive in detecting E. granulosus DNA in feces of necropsied dogs (73.7% and 100%, respectively). The "Abbasi" primers detected 52.6% of E. granulosus infected dogs but were the most species-specific, cross-reacting only with Echinococcus shiquicus (tissue 90.9%; feces 75%). The Stefanic primers were the least specific (tissue, 27.3%; feces, 25%) for E. granulosus. The Dinkel primers also showed inter-species cross-reactivity (tissue, 63.6%; feces, 100%) but were found to be strain-specific for the E. granulosus G1 sheep genotype. Improvement of PCR tests for Echinococcus species and subspecific variants should rely on the use of less-conserved genes and development of protocols that improve the quality and quantity of DNA extracted from feces.

Patent and pre-patent detection of Echinococcus granulosus genotypes in the definitive host.

The detection of Echinococcus granulosus in dogs is important for epidemiological surveillance and evaluation of cystic hydatic disease control programs. We report the efficacy of two PCR-based methods to detect patent and pre-patent infection in dogs experimentally infected with E. granulosus. The detection is based on amplification of a fragment of a mitochondrial gene (Mit-PCR) and a DNA repetitive element (Rep-PCR) of E. granulosus. We tested the ability of both methods to detect several genotypes of the parasite. Both PCR methods could detect E. granulosus in pre-patent and patent periods, even when microscopical observation of eggs resulted negative in fecal samples. The Mit-PCR produced the same amplification pattern for all the parasite genotypes tested while the amplification patterns with the Rep-PCR differed among groups of strains. Fecal samples collected from dogs of an endemic area were diagnosed with more sensitivity than arecoline hydrobromide purgation. These molecular methods could be applied in the confirmation of coproantigen-positive fecal samples and to verify the success of control programs.