Pasión y razón en el ejercicio de la política : La organización de la defensa militante

Fil: Garros, Mayra. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina

The Culicoides of the subgenus Avaritia (Diptera: Ceratopogonidae) in the Palaearctic region: through unsuspected diversity with epidemiologic implications

The biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are known vectors of pathogens especially Orbivirus of the Reoviridae family such as bluetongue, african horse sickness, epizootic hemorrhagic disease and more recently Schmallenberg viruses. The western Europe and the Mediterranean basin faced bluetongue transmission with the 6 species belonging to the Avaritia subgenus recorded in these areas including the species closely related to the Obsoletus group. To date, no study encompasses the whole number of species belonging to a subgenus at a biogeographical scale. The data presented focus on local or on country fauna scale using a classification based on subgenus and/or group of species. Among the latter, the presence of cryptic species has been pointed out by recent phylogenetic studies. These classification discrepancies between authors since decades result in a taxonomic imbroglio. Recent findings of specimens with tricky morphology related to the Obsoletus group in France led us to better describe the systematic and the taxonomy of the subgenus Avaritia in the Palaearctic region. This study focuses on investigating the phylogenetic relationships between and within the Avaritia species of the Palaeactic region with a special interest for the Obsoletus group at a world scale. Voucher specimens were selected based on morphology, sequenced for the CO1 region (mtDNA) and then slide-mounted allowing a morphological interpretation of the results afterwards. A total of 82 CO1 sequences including 43 sequences from the GenBank database were analyzed by Bayesian inference and the resulting tree was used to study species boundaries. The Barcoding gap was evaluated for the closest related species not supported by the species delimitation analysis. Within the Avaritia subgenus, we propose a new systematic scheme for the species of the Obsoletus group including C. scoticus as a basal clade with the two following complexes: the Sanguisuga complex with the species C. abchazicus, C. gornostaevae, C. sanguisuga and C. sinanoensis; the Obsoletus complex made of the species C. obsoletus, C. montanus and a new species. Culicoides filicinus, absent in this analysis, could not be placed in the proposed scheme. The existence of Dewulfi and Chiopterus complex is discussed. The results of the species boundaries analysis and the presence of discriminant morphological characters support the evidence of two new species under description with one in the Obsoletus complex. We also point out new records of C. gornostaevae (France, Sweden and Switzerland) and C. aff. sanguisuga (Sweden). The subgenus Avaritia includes worldwide major vectors of Orbivirus. The revealed diversity increases up to 10 species in western Europe and questions about the possible vector roles in Europe of these newly recorded species. Evaluating the vector role of the Avaritia species in bluetongue and other viruses transmission reaches a higher challenging level for the European teams. (Texte intégral

Avabase: a taxonomic and epidemiological plateform resource for arthropods of interest for animal health

Despite the general acknowledge that taxonomy is primordial, the decline in taxonomy and skills base for identifying and describing biodiversity is drastically declining. This is particularly crucial when dealing with arthropod pests, nuisance or vector species. Besides, recent or on-going emergence or remergence of vector-borne diseases in temperate areas regain interest to neglected or newly focused arthropods groups. Species identification is usually based on comparison with voucher or type specimens present in reference collection or done using an identification key. The recent development of DNA barcoding has also increased molecular species identification, especially for sibling species or species group, based on molecular polymorphism with its controversial. However, reference collection can be difficult to access and are generally not accessible online, and the quality of molecular data is difficult to check. This highlights the importance of reference collection and the need for a high standard dissemination among field workers, scientists and taxonomists. For arthropods of interest to animal health, few websites were available gathering information on taxonomy, epidemiology and sharing data such as pictures of morphological features and molecular sequences. Avabase is an online database (http://avabase.cirad.fr/) for vector arthropods of interest for animal health. It is a free tool available to any labs or institutes willing to share and disseminate their reference collection of arthropods. It gathers species sheets with up-todate data on taxonomy and epidemiology and manages the collection of voucher specimens and DNA data. Today, the database presents data for the Culicoides collection available at Cirad. Soon, the historical collection of Ixodidae ticks collected by P.C. Morel and the complete fauna of Glossina flies will also be processed. We hope this online database will help sharing taxonomic expertise and knowledge as well as contribute and participate to the systematic review of important arthropod groups. (Texte intégral

Repellent properties of various essential oils and synthetic and natural products against Culicoides nubeculosus and C. obsoletus (Diptera: Ceratopogonidae), vectors of Orbivirus

Control of animal arbovirus transmission by Culicoides biting midges vectors is almost exclusively performed using pour-on pyrethroid insecticides on ruminants. Alternative strategies to synthetic insecticides, such as repellent essential oils, should be developed. Biting midges were exposed to various essential oils (geranium, lavender, lemongrass, lemon-eucalyptus, peppermint, tea tree), other natural (Neem) or synthetic (DEET) repellents, and deltamethrin diluted in ethanol. The tests were performed by applying the products to the membrane of an artificial blood-feeding unit (Hemotek) for laboratoryreared C. nubeculosus and a sugar solution for C. obsoletus, due to unsuccessful engorgement on the feeding unit of wild caught individuals. Blood-feeding on ethanol-treated control was about 70% for C. nubeculosus. Immediately following application, DEET at 5 and 20%, lemongrass (Cymbopogon citratus) and geranium (Pelargonium asperum) at 5% were consistently superior to the other products at repelling C. nubeculosus from blood-feeding. Two hours after application, the blood-feeding inhibition of most of the products declined sharply. DEET and deltamethrin caused significant mortality compared to the control. For field collected C. obsoletus, engorgement on sugar solution was variable but usually ranged from 40 to 50% for the control. DEET, lemongrass and geranium repelled 100% of the biting midges from sugar feeding for one hour. Mortality was significant for DEET, deltamethrin and lemongrass. The effective dose to protection was determined for lemongrass, geranium and deltamethrin. (Texte intégral

Assessment of vector/host contact: comparison of animal-baited traps and UV-light/suction trap for collecting Culicoides biting midges (Diptera: Ceratopogonidae), vectors of Orbiviruses

BACKGROUND The emergence and massive spread of bluetongue in Western Europe during 2006-2008 had disastrous consequences for sheep and cattle production and confirmed the ability of Palaearctic Culicoides (Diptera: Ceratopogonidae) to transmit the virus. Some aspects of Culicoides ecology, especially host-seeking and feeding behaviors, remain insufficiently described due to the difficulty of collecting them directly on a bait animal, the most reliable method to evaluate biting rates.Our aim was to compare typical animal-baited traps (drop trap and direct aspiration) to both a new sticky cover trap and a UV-light/suction trap (the most commonly used method to collect Culicoides). METHODS/RESULTS Collections were made from 1.45 hours before sunset to 1.45 hours after sunset in June/July 2009 at an experimental sheep farm (INRA, Nouzilly, Western France), with 3 replicates of a 4 sites×4 traps randomized Latin square using one sheep per site. Collected Culicoides individuals were sorted morphologically to species, sex and physiological stages for females. Sibling species were identified using a molecular assay. A total of 534 Culicoides belonging to 17 species was collected. Abundance was maximal in the drop trap (232 females and 4 males from 10 species) whereas the diversity was the highest in the UV-light/suction trap (136 females and 5 males from 15 species). Significant between-trap differences abundance and parity rates were observed. CONCLUSIONS Only the direct aspiration collected exclusively host-seeking females, despite a concern that human manipulation may influence estimation of the biting rate. The sticky cover trap assessed accurately the biting rate of abundant species even if it might act as an interception trap. The drop trap collected the highest abundance of Culicoides and may have caught individuals not attracted by sheep but by its structure. Finally, abundances obtained using the UV-light/suction trap did not estimate accurately Culicoides biting rate.This study was funded partly by CIRAD and partly by the Ministry of Agriculture, Food, Fishing and Rural Affairs

What is new about the Culicoides identification freeware?

In the framework of Medreonet workpackage on "Regional surveillance of vectors", a Culicoides identification key based on morphology is proposed. This key will help to identify the different Culicoides species, including those of the Palaearctic region. The tool will be available in a freeware version and in a web version. At time of writing, the key was not yet available but a first draft version was to be presented soon after to Culicoides taxonomists so as to improve it. Currently, females of 85 species including 9 morphological variations are included in a database of 63 descriptors codified in 172 states. These descriptors and states of descriptors were discussed and validated by the participants of the last taxonomic meeting in Strasbourg, France, in March 2009. (Texte intégral