Publications by authors named "Jean-Claude Delécolle"

27 Publications

  • Page 1 of 1

A phylogenetic analysis of the biting midges belonging to Culicoides Latreille (Diptera: Ceratopogonidae) subgenus Avaritia using molecular data.

Parasit Vectors 2020 May 12;13(1):243. Epub 2020 May 12.

ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.

Background: Within the genus Culicoides (Diptera: Ceratopogonidae), the subgenus Avaritia is of particular interest as it contains a significant number of economically important vector species. Disagreements about the systematic classification of species within this subgenus have resulted in a taxonomic imbroglio.

Methods: A molecular phylogeny of the subgenus Avaritia was conducted to test the existing systematic classification, which is based on phenetic assessment of morphological characters. Three nuclear ribosomal markers, internal transcribed spacer 1 and 2 (ITS1, ITS2), 5.8S, and three mitochondrial markers, cytochrome c oxidase subunit 1 and 2, and cytochrome b (cox1, cox2 and cytb), were obtained for 37 species of the subgenus Avaritia from all six biogeographical regions. Phylogenetic reconstructions using these genes independently and in combination were implemented using Bayesian inference analysis and maximum likelihood methods.

Results: Phylogenetic reconstructions gave strong support to several monophyletic groups within the subgenus Avaritia. Both C. actoni and C. pusillus formed a single clade with C. grahamii so their respective groups, the Actoni and Pusillus groups, have been merged with the Grahamii group. Some support was provided for the Boophagus and Jacobsoni groups. A group of species currently placed into the Orientalis group clustered in a clade with poor support. The Obsoletus group was defined as a sister clade to all other Avaritia groups. The clade including the Imicola group was well supported based on phylogenetic criteria.

Conclusions: This phylogenetic study combining five distinct molecular markers has provided meaningful insights into the systematic relationships of Culicoides (Avaritia) and highlighted future directions to continue the study of this subgenus. While the cox2 marker appeared to be useful to investigate closely related species, the 5.8S marker was highly conserved and uninformative. Further investigations including species absent from this work are needed to confirm the proposed systematic scheme. However, this systematic scheme can now serve as a foundation to investigate cryptic species affiliation within the subgenus. We advocate that future studies employ a combination of morphological and molecular analyses.
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http://dx.doi.org/10.1186/s13071-020-04111-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216621PMC
May 2020

Modelling the monthly abundance of Culicoides biting midges in nine European countries using Random Forests machine learning.

Parasit Vectors 2020 Apr 15;13(1):194. Epub 2020 Apr 15.

Division for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark (DTU), Lyngby, Denmark.

Background: Culicoides biting midges transmit viruses resulting in disease in ruminants and equids such as bluetongue, Schmallenberg disease and African horse sickness. In the past decades, these diseases have led to important economic losses for farmers in Europe. Vector abundance is a key factor in determining the risk of vector-borne disease spread and it is, therefore, important to predict the abundance of Culicoides species involved in the transmission of these pathogens. The objectives of this study were to model and map the monthly abundances of Culicoides in Europe.

Methods: We obtained entomological data from 904 farms in nine European countries (Spain, France, Germany, Switzerland, Austria, Poland, Denmark, Sweden and Norway) from 2007 to 2013. Using environmental and climatic predictors from satellite imagery and the machine learning technique Random Forests, we predicted the monthly average abundance at a 1 km resolution. We used independent test sets for validation and to assess model performance.

Results: The predictive power of the resulting models varied according to month and the Culicoides species/ensembles predicted. Model performance was lower for winter months. Performance was higher for the Obsoletus ensemble, followed by the Pulicaris ensemble, while the model for Culicoides imicola showed a poor performance. Distribution and abundance patterns corresponded well with the known distributions in Europe. The Random Forests model approach was able to distinguish differences in abundance between countries but was not able to predict vector abundance at individual farm level.

Conclusions: The models and maps presented here represent an initial attempt to capture large scale geographical and temporal variations in Culicoides abundance. The models are a first step towards producing abundance inputs for R modelling of Culicoides-borne infections at a continental scale.
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http://dx.doi.org/10.1186/s13071-020-04053-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161244PMC
April 2020

Red deer () Did Not Play the Role of Maintenance Host for Bluetongue Virus in France: The Burden of Proof by Long-Term Wildlife Monitoring and Snapshots.

Viruses 2019 09 27;11(10). Epub 2019 Sep 27.

UMR Virologie, INRA, Ecole Nationale Vétérinaire d'Alfort, laboratoire de santé animale d'Alfort, ANSES, Université Paris-Est, 94700 Maisons-Alfort, France, (C.V.).

Bluetongue virus (BTV) is a -borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer () (RD) is considered a potential BTV reservoir, but persistent sylvatic cycle has not yet been demonstrated. In this paper, we explored the dynamics of BTV1 and BTV8 serotypes in the RD in France, and the potential role of that species in the re-emergence of BTV8 in livestock by 2015 (i.e., 5 years after the former last domestic cases). We performed 8 years of longitudinal monitoring (2008-2015) among 15 RD populations and 3065 individuals. We compared communities and feeding habits within domestic and wild animal environments (51,380 samples). diversity (>30 species) varied between them, but bridge-species able to feed on both wild and domestic hosts were abundant in both situations. Despite the presence of competent vectors in natural environments, BTV1 and BTV8 strains never spread in RD along the green corridors out of the domestic outbreak range. Decreasing antibody trends with no PCR results two years after the last domestic outbreak suggests that seropositive young RD were not recently infected but carried maternal antibodies. We conclude that RD did not play a role in spreading or maintaining BTV in France.
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http://dx.doi.org/10.3390/v11100903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832957PMC
September 2019

Update of the species checklist of Culicoides Latreille, 1809 biting midges (Diptera: Ceratopogonidae) of Morocco.

Parasit Vectors 2019 Sep 24;12(1):459. Epub 2019 Sep 24.

ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.

Background: Investigations of Culicoides fauna, including inventories, were carried out in Morocco at different periods after the country had faced major bluetongue and African horse sickness outbreaks. However, no comprehensive reference publication has provided a clear overview of the Culicoides species diversity. This study reviewed available data on Culicoides biting midge species in Morocco from 1968 to 2015 (published and grey literature in French and English) in order to revise the current checklist, in light of state of the art taxonomic and systematic knowledge, and confirmed the checklist with morphological and molecular identifications of specimens collected from the region of Rabat.

Methods: Literature related to Culicoides collections in Morocco was collated. Authors were contacted to obtain raw data and additional information for the collections. Fresh Culicoides material was collected and examined from two sites around Rabat, the capital of Morocco. Each collected individual was examined and morphologically identified, if possible, to the species level. In addition, molecular identification was performed to separate closely related species, to confirm difficult morphological identifications and to confirm new species records.

Results: A total of 6121 individuals of Culicoides spp. were collected and analyzed and at least 17 species were identified: C. cataneii/C. gejgelensis, C. circumscriptus, C. fagineus, C. festivipennis, C. imicola, C. jumineri, C. kingi, C. longipennis, C. montanus, C. newsteadi, C. obsoletus, C. paolae, C. parotti, C. puncticollis, C. sahariensis, C. scoticus and C. subfagineus. Seven species were confirmed using phylogenetic analyses. Two new species records for Morocco are reported: C. paolae and C. subfagineus.

Conclusions: The Moroccan fauna of Culicoides now includes 54 valid species. Further work would certainly increase this total, as one of the clades we identified was not affiliated to any described and valid species.
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http://dx.doi.org/10.1186/s13071-019-3720-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6757417PMC
September 2019

Monthly variation in the probability of presence of adult Culicoides populations in nine European countries and the implications for targeted surveillance.

Parasit Vectors 2018 Nov 29;11(1):608. Epub 2018 Nov 29.

Division for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark (DTU), Lyngby, Denmark.

Background: Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are small hematophagous insects responsible for the transmission of bluetongue virus, Schmallenberg virus and African horse sickness virus to wild and domestic ruminants and equids. Outbreaks of these viruses have caused economic damage within the European Union. The spatio-temporal distribution of biting midges is a key factor in identifying areas with the potential for disease spread. The aim of this study was to identify and map areas of neglectable adult activity for each month in an average year. Average monthly risk maps can be used as a tool when allocating resources for surveillance and control programs within Europe.

Methods: We modelled the occurrence of C. imicola and the Obsoletus and Pulicaris ensembles using existing entomological surveillance data from Spain, France, Germany, Switzerland, Austria, Denmark, Sweden, Norway and Poland. The monthly probability of each vector species and ensembles being present in Europe based on climatic and environmental input variables was estimated with the machine learning technique Random Forest. Subsequently, the monthly probability was classified into three classes: Absence, Presence and Uncertain status. These three classes are useful for mapping areas of no risk, areas of high-risk targeted for animal movement restrictions, and areas with an uncertain status that need active entomological surveillance to determine whether or not vectors are present.

Results: The distribution of Culicoides species ensembles were in agreement with their previously reported distribution in Europe. The Random Forest models were very accurate in predicting the probability of presence for C. imicola (mean AUC = 0.95), less accurate for the Obsoletus ensemble (mean AUC = 0.84), while the lowest accuracy was found for the Pulicaris ensemble (mean AUC = 0.71). The most important environmental variables in the models were related to temperature and precipitation for all three groups.

Conclusions: The duration periods with low or null adult activity can be derived from the associated monthly distribution maps, and it was also possible to identify and map areas with uncertain predictions. In the absence of ongoing vector surveillance, these maps can be used by veterinary authorities to classify areas as likely vector-free or as likely risk areas from southern Spain to northern Sweden with acceptable precision. The maps can also focus costly entomological surveillance to seasons and areas where the predictions and vector-free status remain uncertain.
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http://dx.doi.org/10.1186/s13071-018-3182-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6267925PMC
November 2018

Spatial and temporal variation in the abundance of Culicoides biting midges (Diptera: Ceratopogonidae) in nine European countries.

Parasit Vectors 2018 02 27;11(1):112. Epub 2018 Feb 27.

Division for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark (DTU), Copenhagen, Denmark.

Background: Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are vectors of bluetongue virus (BTV), African horse sickness virus and Schmallenberg virus (SBV). Outbreaks of both BTV and SBV have affected large parts of Europe. The spread of these diseases depends largely on vector distribution and abundance. The aim of this analysis was to identify and quantify major spatial patterns and temporal trends in the distribution and seasonal variation of observed Culicoides abundance in nine countries in Europe.

Methods: We gathered existing Culicoides data from Spain, France, Germany, Switzerland, Austria, Denmark, Sweden, Norway and Poland. In total, 31,429 Culicoides trap collections were available from 904 ruminant farms across these countries between 2007 and 2013.

Results: The Obsoletus ensemble was distributed widely in Europe and accounted for 83% of all 8,842,998 Culicoides specimens in the dataset, with the highest mean monthly abundance recorded in France, Germany and southern Norway. The Pulicaris ensemble accounted for only 12% of the specimens and had a relatively southerly and easterly spatial distribution compared to the Obsoletus ensemble. Culicoides imicola Kieffer was only found in Spain and the southernmost part of France. There was a clear spatial trend in the accumulated annual abundance from southern to northern Europe, with the Obsoletus ensemble steadily increasing from 4000 per year in southern Europe to 500,000 in Scandinavia. The Pulicaris ensemble showed a very different pattern, with an increase in the accumulated annual abundance from 1600 in Spain, peaking at 41,000 in northern Germany and then decreasing again toward northern latitudes. For the two species ensembles and C. imicola, the season began between January and April, with later start dates and increasingly shorter vector seasons at more northerly latitudes.

Conclusion: We present the first maps of seasonal Culicoides abundance in large parts of Europe covering a gradient from southern Spain to northern Scandinavia. The identified temporal trends and spatial patterns are useful for planning the allocation of resources for international prevention and surveillance programmes in the European Union.
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http://dx.doi.org/10.1186/s13071-018-2706-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828119PMC
February 2018

New species of the genus Culicoides (Diptera Ceratopogonidae) for Tunisia, with detection of Bluetongue viruses in vectors.

Vet Ital 2017 Dec;53(4):357-366

Université Tunis El Manar, Institut de la Recherche Vétérinaire de Tunisie, 20 Rue Djebel Lakdhar, 1006 La Rabta, Tunis, Tunisia.

Bluetongue virus (BTV) and Epizootic haemorrhagic disease virus (EHDV) are double-stranded RNA orbiviruses of the Reoviridae family. Bluetongue virus and EHDV infect domestic and wild ruminants and they are transmitted by biting midges of the genus Culicoides (Diptera: Ceratopogonidae). Since 1999, BTV outbreaks have occurred in Tunisia and 4 serotypes, BTV2, BTV1, BTV4 and BTV3, were involved in 2000, 2006, 2009, and 2016, respectively. Epizootic haemorrhagic disease was detected for the rst time in Tunisia and in other Northern African countries in 2006. These incursions have caused considerable economic losses. Our study had the goal to describe diversity, distribution, and seasonal dynamics of Culicoides. Fourteen sampling sites were chosen throughout the country and 2-night trapping of midges was performed monthly from June 2006 to July 2008. A total of 11,582 Culicoides specimens were collected from 336 light traps, comprising 25 species, of which 7 were identi ed for the rst time in Tunisia, increasing to 35 the total number of Culicoides species now reported in this country. Twenty-three pools of parous females belonging to the Culicoides imicola and Culicoides kingi were tested for detection of BTV and EHDV by molecular assays. Both BTV1 and BTV4 were detected in C. imicola.
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http://dx.doi.org/10.12834/VetIt.986.5216.2DOI Listing
December 2017

Culicoides (Diptera: Ceratopogonidae) midges, the vectors of African horse sickness virus--a host/vector contact study in the Niayes area of Senegal.

Parasit Vectors 2015 Jan 21;8:39. Epub 2015 Jan 21.

ISRA, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Route Front de Terre, Dakar, Senegal.

Background: African horse sickness (AHS) is an equine disease endemic to Senegal. The African horse sickness virus (AHSV) is transmitted to the mammalian hosts by midges of the Culicoides Latreille genus. During the last epizootic outbreak of AHS in Senegal in 2007, 1,169 horses died from this disease entailing an estimated cost of 1.4 million euros. In spite of the serious animal health and economic implications of AHS, very little is known about determinants involved in transmission such as contact between horses and the Culicoides species suspected of being its vectors.

Methods: The monthly variation in host/vector contact was determined in the Niayes area, Senegal, an area which was severely affected by the 2007 outbreak of AHS. A horse-baited trap and two suction light traps (OVI type) were set up at each of five sites for three consecutive nights every month for one year.

Results: Of 254,338 Culicoides midges collected 209,543 (82.4%) were female and 44,795 (17.6%) male. Nineteen of the 41 species collected were new distribution records for Senegal. This increased the number of described Culicoides species found in Senegal to 53. Only 19 species, of the 41 species found in light trap, were collected in the horse-baited trap (23,669 specimens) largely dominated by Culicoides oxystoma (22,300 specimens, i.e. 94.2%) followed by Culicoides imicola (482 specimens, i.e. 2.0%) and Culicoides kingi (446 specimens, i.e. 1.9%).

Conclusions: Culicoides oxystoma should be considered as a potential vector of AHSV in the Niayes area of Senegal due to its abundance on horses and its role in the transmission of other Culicoides-borne viruses.
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http://dx.doi.org/10.1186/s13071-014-0624-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4307892PMC
January 2015

Morphological and molecular analysis of the genus Culicoides (Diptera: Ceratopogonidae) in Slovakia with five new records.

Zootaxa 2014 Oct 13;3872(5):541-60. Epub 2014 Oct 13.

Institute of Parasitology and Tropical Pathology (IPPTS), Medicine faculty, EA7292, 3 rue Koeberlé, F-67000 Strasbourg, France. EID Méditerranée, 165 av Paul Rimbaud, F-34184 Montpellier, France; Email: unknown.

The biodiversity of Culicoides from eastern Slovakia was investigated by light trapping. An integrative taxonomy approach combining DNA barcode sequence and morphological analyses was used to accurately identify specimens. Five species were newly recorded from Slovakia: Culicoides picturatus Kremer & Deduit, C. gejgelensis Dzhafarov, C. clastrieri Callot et al., C. griseidorsum Kieffer and C. odiatus Austen. The checklist of the Culicoides species recorded from SK has been updated to 63 species and barcode sequence data is provided for 8 species not previously available on GenBank. Conflict between results from molecular and morphological analyses resulted in the discovery of some potentially new cryptic species and the inability of DNA barcodes to distinguish C. festivipennis Kieffer from C. clastrieri, C. salinarius Kieffer from C. manchuriensis Tokunaga and C. pallidicornis Kieffer from C. subfasciipennis Kieffer. These conflicts suggest further study is required to clarify the status of these species. 
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http://dx.doi.org/10.11646/zootaxa.3872.5.6DOI Listing
October 2014

Limits of a rapid identification of common Mediterranean sandflies using polymerase chain reaction-restriction fragment length polymorphism.

Mem Inst Oswaldo Cruz 2014 Jul 6;109(4):466-72. Epub 2014 Jun 6.

Agence Nationale de la Sécurité Sanitaire de l?Alimentation, de l?Enviromment et du Travail, Faculté de Pharmacie, Université de Reims Champagne-Ardenne, Reims, France.

A total of 131 phlebotomine Algerian sandflies have been processed in the present study. They belong to the species Phlebotomus bergeroti, Phlebotomus alexandri, Phlebotomus sergenti, Phlebotomus chabaudi, Phlebotomus riouxi, Phlebotomus perniciosus, Phlebotomus longicuspis, Phlebotomus perfiliewi, Phlebotomus ariasi, Phlebotomus chadlii, Sergentomyia fallax, Sergentomyia minuta, Sergentomyia antennata, Sergentomyia schwetzi, Sergentomyia clydei, Sergentomyia christophersi and Grassomyia dreyfussi. They have been characterised by sequencing of a part of the cytochrome b (cyt b), t RNA serine and NADH1 on the one hand and of the cytochrome C oxidase I of the mitochondrial DNA (mtDNA) on the other hand. Our study highlights two sympatric populations within P. sergenti in the area of its type-locality and new haplotypes of P. perniciosus and P. longicuspis without recording the specimens called lcx previously found in North Africa. We tried to use a polymerase chain reaction-restriction fragment length polymorphism method based on a combined double digestion of each marker. These method is not interesting to identify sandflies all over the Mediterranean Basin.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4155849PMC
http://dx.doi.org/10.1590/0074-0276130584DOI Listing
July 2014

Towards the PCR-based identification of Palaearctic Culicoides biting midges (Diptera: Ceratopogonidae): results from an international ring trial targeting four species of the subgenus Avaritia.

Parasit Vectors 2014 May 14;7:223. Epub 2014 May 14.

Cirad, UMR15 CMAEE, 34398 Montpellier, France.

Background: Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are biological vectors of internationally important arboviruses. To understand the role of Culicoides in the transmission of these viruses, it is essential to correctly identify the species involved. Within the western Palaearctic region, the main suspected vector species, C. obsoletus, C. scoticus, C. dewulfi and C. chiopterus, have similar wing patterns, which makes it difficult to separate and identify them correctly.

Methods: In this study, designed as an inter-laboratory ring trial with twelve partners from Europe and North Africa, we assess four PCR-based assays which are used routinely to differentiate the four species of Culicoides listed above. The assays based on mitochondrial or ribosomal DNA or microarray hybridisation were tested using aliquots of Culicoides DNA (extracted using commercial kits), crude lysates of ground specimens and whole Culicoides (265 individuals), and non-Culicoides Ceratopogonidae (13 individuals) collected from across Europe.

Results: A total of 800 molecular assays were implemented. The in-house assays functioned effectively, although specificity and sensitivity varied according to the molecular marker and DNA extraction method used. The Obsoletus group specificity was overall high (95-99%) while the sensitivity varied greatly (59.6-100%). DNA extraction methods impacted the sensitivity of the assays as well as the type of sample used as template for the DNA extraction.

Conclusions: The results are discussed in terms of current use of species diagnostic assays and the future development of molecular tools for the rapid differentiation of cryptic Culicoides species.
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http://dx.doi.org/10.1186/1756-3305-7-223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4024274PMC
May 2014

The emergence of Schmallenberg virus across Culicoides communities and ecosystems in Europe.

Prev Vet Med 2014 Oct 18;116(4):360-9. Epub 2014 Mar 18.

Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.

Schmallenberg virus (SBV), a novel arboviral pathogen, has emerged and spread across Europe since 2011 inflicting congenital deformities in the offspring of infected adult ruminants. Several species of Culicoides biting midges (Diptera: Ceratopogonidae) have been implicated in the transmission of SBV through studies conducted in northern Europe. In this study Culicoides from SBV outbreak areas of mainland France and Italy (Sardinia) were screened for viral RNA. The role of both C. obsoletus and the Obsoletus complex (C. obsoletus and C. scoticus) in transmission of SBV were confirmed in France and SBV was also discovered in a pool of C. nubeculosus for the first time, implicating this species as a potential vector. While collections in Sardinia were dominated by C. imicola, only relatively small quantities of SBV RNA were detected in pools of this species and conclusive evidence of its potential role in transmission is required. In addition to these field-based studies, infection rates in colony-derived individuals of C. nubeculosus and field-collected C. scoticus are also examined in the laboratory. Rates of infection in C. nubeculosus were low, confirming previous studies, while preliminary examination of C. scoticus demonstrated that while this species can replicate SBV to a potentially transmissible level, further work is required to fully define comparative competence between species in the region. Finally, the oral competence for SBV of two abundant and widespread mosquito vector species in the laboratory is assessed. Neither Aedes albopictus nor Culex pipiens were demonstrated to replicate SBV to transmissible levels and appear unlikely to play a major role in transmission. Other vector competence data produced from studies across Europe to date is then comprehensively reviewed and compared with that generated previously for bluetongue virus.
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http://dx.doi.org/10.1016/j.prevetmed.2014.03.007DOI Listing
October 2014

First record of Culicoides oxystoma Kieffer and diversity of species within the Schultzei group of Culicoides Latreille (Diptera: Ceratopogonidae) biting midges in Senegal.

PLoS One 2013 30;8(12):e84316. Epub 2013 Dec 30.

Cirad, UMR15 Contrôle des Maladies; INRA, UMR1309 Contrôle des Maladies, Montpellier, France.

The Schultzei group of Culicoides Latreille (Diptera: Ceratopogonidae) is distributed throughout Africa to northern Asia and Australasia and includes several potential vector species of livestock pathogens. The taxonomy of the species belonging to this species group is confounded by the wide geographical distribution and morphological variation exhibited by many species. In this work, morphological and molecular approaches were combined to assess the taxonomic validity of the species and morphological variants of the Schultzei group found in Senegal by comparing their genetic diversity with that of specimens from other geographical regions. The species list for Senegal was updated with four species: Culicoides kingi, C. oxystoma, C. enderleini and C. nevilli being recorded. This is the first record of C. oxystoma from Africa south of Sahara, and its genetic relationship with samples from Israel, Japan and Australia is presented. This work provides a basis for ecological studies of the seasonal and spatial dynamics of species of this species group that will contribute to better understanding of the epidemiology of the viruses they transmit.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0084316PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3875552PMC
August 2014

Morphological description of the fourth instar larva: Culicoides cataneii and Culicoides sahariensis (Diptera: Ceratopogonidae).

Zootaxa 2013 ;3666:160-70

Laboratory of Parasitology code 99 UR/08-05, Department of Clinical Biology B, Faculty of pharmacy Monastir, Tunisia.

This study was carried out of the region of Monastir in Central Tunisia, between July and August 2010. Larvae were collected using a floatation technique with magnesium sulfate in mud samples. The fourth instar larva of Culicoides cataneii Clastrier, 1957 and Culicoides sahariensis Callot, Kremer, Bailly-Choumara, 1970 are described, illustrated and drawn. Measurements of instars IV are also presented. This is the first record of Culicoides cataneii and Culicoides sahariensis (Diptera: Ceratopogonidae) to Tunisia.
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http://dx.doi.org/10.11646/zootaxa.3666.2.3DOI Listing
August 2015

Description of Culicoides paradoxalis sp. nov. from France and Portugal (Diptera: Ceratopogonidae).

Zootaxa 2013 Dec 4;3745:243-56. Epub 2013 Dec 4.

Institut de Parasitologie et de Pathologie Tropicale de Strasbourg (IPPTS) EA7292, 3 rue Koeberlé, F-67000 Strasbourg, France; Email: unknown.

A new species, Culicoides paradoxalis Ramilo and Delécolle (Diptera: Ceratopogonidae), is described from specimens collected in France (Corsica and southeast region) and Portugal. This species resembles Culicoides lupicaris Downes and Kettle, and can be distinguished from this species and from Culicoides newsteadi Austen by its wing pattern, in addition to the absence of spines on the tarsomere 4 of female mid leg. In male, the presence of two appendices on the sternite 9 together with the absence of sensilla coeloconica on the flagellomere 11 is also useful to distinguish these three species. Separation from other members of the Culicoides subgenus is confirmed by the analysis of the Cytochrome Oxidase I (COI) mitochondrial marker. 
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http://dx.doi.org/10.11646/zootaxa.3745.2.4DOI Listing
December 2013

Development and validation of IIKC: an interactive identification key for Culicoides (Diptera: Ceratopogonidae) females from the Western Palaearctic region.

Parasit Vectors 2012 Jul 9;5:137. Epub 2012 Jul 9.

IPPTS, Université de Strasbourg, EA 4438, 67000, Strasbourg, France.

Background And Methods: The appearance of bluetongue virus (BTV) in 2006 within northern Europe exposed a lack of expertise and resources available across this region to enable the accurate morphological identification of species of Culicoides Latreille biting midges, some of which are the major vectors of this pathogen. This work aims to organise extant Culicoides taxonomic knowledge into a database and to produce an interactive identification key for females of Culicoides in the Western Palaearctic (IIKC: Interactive identification key for Culicoides). We then validated IIKC using a trial carried out by six entomologists based in this region with variable degrees of experience in identifying Culicoides.

Results: The current version of the key includes 98 Culicoides species with 10 morphological variants, 61 descriptors and 837 pictures and schemes. Validation was carried out by six entomologists as a blind trial with two users allocated to three classes of expertise (beginner, intermediate and advanced). Slides were identified using a median of seven steps and seven minutes and user confidence in the identification varied from 60% for failed identifications to a maximum of 80% for successful ones. By user class, the beginner group successfully identified 44.6% of slides, the intermediate 56.8% and the advanced 74.3%.

Conclusions: Structured as a multi-entry key, IIKC is a powerful database for the morphological identification of female Culicoides from the Western Palaearctic region. First developed for use as an interactive identification key, it was revealed to be a powerful back-up tool for training new taxonomists and to maintain expertise level. The development of tools for arthropod involvement in pathogen transmission will allow clearer insights into the ecology and dynamics of Culicoides and in turn assist in understanding arbovirus epidemiology.
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http://dx.doi.org/10.1186/1756-3305-5-137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483010PMC
July 2012

First report of 13 species of Culicoides (Diptera: Ceratopogonidae) in mainland Portugal and Azores by morphological and molecular characterization.

PLoS One 2012 19;7(4):e34896. Epub 2012 Apr 19.

Interdisciplinary Centre of Research in Animal Health (CIISA), Veterinary Medicine Faculty, Technical University of Lisbon, Lisbon, Portugal.

The genus Culicoides (Diptera: Ceratopogonidae) contains important vectors of animal and human diseases, including bluetongue, African horse sickness and filariosis. A major outbreak of bluetongue occurred in mainland Portugal in 2004, forty eight years after the last recorded case. A national Entomological Surveillance Plan was initiated in mainland Portugal, Azores and the Madeira archipelagos in 2005 in order to better understand the disease and facilitate policy decisions. During the survey, the most prevalent Culicoides species in mainland Portugal was C. imicola (75.3%) and species belonging to the Obsoletus group (6.5%). The latter were the most prevalent in Azores archipelago, accounting for 96.7% of the total species identified. The Obsoletus group was further characterized by multiplex Polymerase Chain Reaction to species level showing that only two species of this group were present: C. obsoletus sensu strictu (69.6%) and C. scoticus (30.4%). Nine species of Culicoides were detected for the first time in mainland Portugal: C. alazanicus, C. bahrainensis, C. deltus, C. lupicaris, C. picturatus, C. santonicus, C. semimaculatus, C. simulator and C. subfagineus. In the Azores, C. newsteadi and C. circumscriptus were identified for the first time from some islands, and bluetongue vectors belonging to the Obsoletus group (C. obsoletus and C. scoticus) were found to be widespread.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0034896PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334969PMC
August 2012

Simultaneous quantification of the relative abundance of species complex members: application to Culicoides obsoletus and Culicoides scoticus (Diptera: Ceratopogonidae), potential vectors of bluetongue virus.

Vet Parasitol 2011 Dec 12;182(2-4):297-306. Epub 2011 Jun 12.

Institut de Parasitologie et de Pathologie Tropicale, Université de Strasbourg, EA 4438, 67000 Strasbourg, France.

The two sympatric sibling species Culicoides obsoletus (Meigen) and Culicoides scoticus Downes and Kettle (Diptera: Ceratopogonidae), are known to be competent vectors for bluetongue virus in the Palaearctic region. However, morphological identification of constituent species is only readily applicable to adult males and these two species distinguishing traits have overlapping character states. As their vector competence may differ in space and time, the correct identification and quantification of specimens of both species are essential for understanding bluetongue epidemiology. However, no molecular tools are available for high-throughput identification of the two species. We therefore developed a quantitative duplex real-time PCR assay to determine the relative abundance of each sibling species in a sample using TaqMan probes. For each species, standard curves were constructed from serial dilutions of purified plasmid DNA containing ITS1-5.8S-ITS2 (rDNA) in the range of 10(-1) to 10(-5)ng/μL. Standard curves were used to quantify samples of mixed C. obsoletus/C. scoticus specimens. Specificity was evaluated with 5156 specimens representing 62 species. Based on the DNA quantities detected according to the standard curves, a quadratic model developed on 1100 males and validated on 555 females was able to predict the relative abundance of each species simultaneously in a one-shot reaction (Pearson coefficient of 0.999). Our assay showed a requirement of two specimens or less for 95% of the predictions, making it highly applicable to field collections. Extensive use of this real-time PCR assay will provide a better understanding of geographical distribution, dynamics, and bionomics on a species level, which is essential for risk assessment. This approach is an important contribution to medical entomology for investigating the vector role of arthropod sibling species.
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http://dx.doi.org/10.1016/j.vetpar.2011.05.052DOI Listing
December 2011

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.

Parasit Vectors 2011 Jun 27;4:119. Epub 2011 Jun 27.

CIRAD, UMR Contrôle des maladies, F-34398 Montpellier, France.

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.
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http://dx.doi.org/10.1186/1756-3305-4-119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145584PMC
June 2011

Contribution to the knowledge of Culicoides (Diptera: Ceratopogonidae) host preferences in France.

Parasitol Res 2011 Mar 22;108(3):657-63. Epub 2010 Oct 22.

Usc Vecpar-ANSES, JE 2533, Faculté de Pharmacie, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51096 Reims, France.

Knowledge on host-feeding pattern of blood-sucking insects helps to understand the epidemiology of a vector-born disease. We determined blood meal origin from blood-fed Culicoides thanks to molecular techniques. A set of primers was used to selectively amplify segment of vertebrates' prepronociceptin gene from abdomen of engorged Culicoides (Diptera: Ceratopogonidae). Vertebrate DNA was successfully amplified in 91% of blood-fed Culicoides assayed. Direct sequencing and comparison of resultant sequences with sequences in GenBank, using BLAST, lead to the specific identification of the host in 100% of the cases. A total of 157 blood-fed females belonging to 13 different Culicoides' species were captured thanks to light traps in different areas of France between 2008 and 2009. Blood meal origin was determined for 143 blood-fed midges: 59 Culicoides obsoletus, 18 Culicoides dewulfi, 16 Culicoides scoticus, 11 Culicoides chiopterus, 10 Culicoides lupicaris, 1 Culicoides pulicaris, 8 Culicoides punctatus, 10 Culicoides pallidicornis, 3 Culicoides achrayi, 2 Culicoides furcillatus, 3 Culicoides brunnicans, 1 Culicoides picturatus and 1 Culicoides poperinghensis. The predominant species in our study belong to the C. obsoletus complex; they are considered as putative vectors of Bluetongue virus in the north of Europe. C. chiopterus sampled fed only on cattle, while blood meal origin of C. dewulfi, C. obsoletus and C. scoticus was diversified. In our sampling, we found that midges were fed mainly on cattle (54%), rabbits (20%), horses (17%), sheep (4%), pigs or wild boars (4%) and human (1%). Cattle DNA was found in at least 11 different species of Culicoides assayed.
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http://dx.doi.org/10.1007/s00436-010-2110-9DOI Listing
March 2011

Suggesting synonymies? Comments on Kiehl et al. (2009) "the European vectors of Bluetongue virus: are there species complexes, single species or races in Culicoides obsoletus and C. pulicaris detectable by sequencing ITS-1, ITS-2 and 18S-rDNA?".

Parasitol Res 2010 Aug 30;107(3):731-4. Epub 2010 May 30.

UMR CMAEE CIRAD-INRA, Contrôle des maladies animales exotiques et émergentes, Campus International de Baillarguet TA-A15/A, bureau A210, Montpellier Cedex 5, France.

Species recognition and identification are crucial in any biological studies, especially when dealing with insect species involved in pathogen transmission. In recent years, molecular approaches have helped the clarification of systematic schemes and taxonomic status. Kiehl et al. (Parasitol Res 105:331-336, 2009) used molecular data to discuss the taxonomic status of biting midge species in the Palaearctic region. In the present work, the statements that "[Thus] there is no molecular support for the existence of a separate species C. montanus" and "[Therefore] probably C. scoticus should be considered only as a race of C. obsoletus" are discussed.
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http://dx.doi.org/10.1007/s00436-010-1921-zDOI Listing
August 2010

Development and evaluation of a real-time quantitative PCR assay for Culicoides imicola, one of the main vectors of bluetongue (BT) and African horse sickness (AHS) in Africa and Europe.

Res Vet Sci 2008 Oct 28;85(2):372-82. Epub 2008 Jan 28.

CIRAD, Centre International de Recherche Agronomique pour le Développement, UPR Contrôle des maladies, F-34398 Montpellier cedex 05, France.

The current microscopy method for identifying the Culicoides imicola Kieffer, 1913 species can be time and labour intensive. There is a need for the development of a rapid and quantitative tool to quantify the biting midges C. imicola ss in light trap catches. A reproducible and sensitive real-time polymerase chain reaction method that targets the internal transcribed spacer (ITS-1) of ribosomal DNA of C. imicola ss species was developed. This real-time PCR assay was first performed on 10-fold serial dilutions of purified plasmid DNA containing specific C. imicola ss ITS-1. It was then possible to construct standard curves with a high correlation coefficient (r2=0.99) in the range of 10(-2)-10(-8) ng of purified DNA. The performances of this PCR were evaluated in comparison with morphological determination on Culicoides trapped along the Mediterranean coastal mainland France. ROC statistical analysis was carried out using morphology as gold standard and the area under the ROC curve had a satisfactory value of 0.9752. The results indicated that this real-time PCR assay holds promise for monitoring C. imicola ss population in both surveillance and research programmes because of its good specificity (92%) and sensitivity (95%).
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http://dx.doi.org/10.1016/j.rvsc.2007.12.001DOI Listing
October 2008

Molecular identification of Western European species of obsoletus complex (Diptera: Ceratopogonidae) by an internal transcribed spacer-1 rDNA multiplex polymerase chain reaction assay.

J Med Entomol 2007 Nov;44(6):1019-25

Entente InterDépartementale pour la démoustication, 165 Avenue Paul Rimbaud, 34184 Montpellier Cedex 4, France.

In southern Europe, orbiviral diseases such as bluetongue (BT) have been assumed to have been largely transmitted by the classical Afro-Asian vector Culicoides imicola Kieffer (Diptera: Ceratopogonidae). Recent outbreaks have occurred in regions where C. imicola is normally absent, supporting the theory that other species belonging to the Obsoletus or Pulicaris complexes may play a role in BT virus transmission. Investigations of the ecology of the species within the former group are hampered by females of member species being extremely difficult to separate by classical morphology. To allow straightforward separation of these species in France, a multiplex polymerase chain reaction-based on internal transcribed spacer (ITS)-1 rDNA was developed to distinguish between Culicoides chiopterus Meigen, Culicoides dewulfi Goetghebuer, Culicoides montanus Shakirjanova, Culicoides obsoletus Meigen, and Culicoides scoticus Downes & Kettle. This tool will be useful in defining both the vector role and larval biotopes of these species in Europe.
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http://dx.doi.org/10.1603/0022-2585(2007)44[1019:miowes]2.0.co;2DOI Listing
November 2007

Molecular detection of Culicoides spp. and Culicoides imicola, the principal vector of bluetongue (BT) and African horse sickness (AHS) in Africa and Europe.

Vet Res 2004 May-Jun;35(3):325-37

CIRAD-EMVT, Campus international de Baillarguet, TA30/G, 34398 Montpellier Cedex 5, France.

Bluetongue (BT) and African Horse Sickness (AHS) are infectious arthropod-borne viral diseases affecting ruminants and horses, respectively. Culicoides imicola Kieffer, 1913, a biting midge, is the principal vector of these livestock diseases in Africa and Europe. Recently bluetongue disease has re-emerged in the Mediterranean Basin and has had a devastating effect on the sheep industry in Italy and on the islands of Sicily, Sardinia, Corsica and the Balearics, but fortunately, has not penetrated onto mainland France and Spain. To survey for the presence of C. imicola, an extensive light-trap network for the collection of Culicoides, was implemented in 2002 in southern mainland France. The morphological identification of Culicoides can be both tedious and time-consuming because its size ranges from 1.5 to 3 mm. Therefore, an ITS1 rDNA polymerase chain reaction (PCR)-based diagnostic assay was developed to rapidly and reliably identify Culicoides spp. and C. imicola. The aim of this work was to set up a rapid test for the detection of C. imicola amongst a pool of insects collected in areas at risk for BT. The sequence similarity of the rDNA (nuclear ribosomal DNA), which is greater within species than between species, is the foundation of its utilisation in species-diagnostic assays. The alignment of the 11 ITS1 sequences of Culicoides obtained from Genbank and EMBL databases helped us to identify one region in the 5' end and one in the 3' end that appear highly conserved. PCR primers were designed within these regions to amplify genus-specific fragments. In order to set up a C. imicola-specific PCR, another forward primer was designed and used in combination with the previously designed reverse primer. These primers proved to be highly specific and sensitive and permitted a rapid diagnostic separation of C. imicola from Culicoides spp.
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http://dx.doi.org/10.1051/vetres:2004015DOI Listing
August 2004