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Kampen H, Werner D. Biting Midges (Diptera: Ceratopogonidae) as Vectors of Viruses. Microorganisms 2023; 11:2706. [PMID: 38004718 PMCID: PMC10673010 DOI: 10.3390/microorganisms11112706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Biting midges of the genus Culicoides occur almost globally and can regionally and seasonally reach high abundances. Most species are hematophagous, feeding on all groups of vertebrates, including humans. In addition to being nuisance pests, they are able to transmit disease agents, with some viruses causing high morbidity and/or mortality in ruminants, horses and humans. Despite their impact on animal husbandry, public health and tourism, knowledge on the biology and ecology of culicoid biting midges and their interactions with ingested pathogens or symbiotic microorganisms is limited. Research is challenging due to unknown larval habitats, the insects' tiny size, the inability to establish and breed most species in the laboratory and the laborious maintenance of colonies of the few species that can be reared in the laboratory. Consequently, the natural transmission of pathogens has experimentally been demonstrated for few species while, for others, only indirect evidence of vector potential exists. Most experimental data are available for Culicoides sonorensis and C. nubeculosus, the only species kept in western-world insectaries. This contribution gives an overview on important biting midge vectors, transmitted viruses, culicoid-borne viral diseases and their epidemiologies and summarizes the little knowledge on interactions between biting midges, their microflora and culicoid-borne arboviruses.
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Affiliation(s)
- Helge Kampen
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493 Greifswald, Germany
| | - Doreen Werner
- Leibniz Centre for Agricultural Landscape Research, 15374 Muencheberg, Germany;
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Aguilar-Vega C, Rivera B, Lucientes J, Gutiérrez-Boada I, Sánchez-Vizcaíno JM. A study of the composition of the Obsoletus complex and genetic diversity of Culicoides obsoletus populations in Spain. Parasit Vectors 2021; 14:351. [PMID: 34217330 PMCID: PMC8254917 DOI: 10.1186/s13071-021-04841-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/11/2021] [Indexed: 11/10/2022] Open
Abstract
Background The Culicoides obsoletus species complex (henceforth ‘Obsoletus complex’) is implicated in the transmission of several arboviruses that can cause severe disease in livestock, such as bluetongue, African horse sickness, epizootic hemorrhagic disease and Schmallenberg disease. Thus, this study aimed to increase our knowledge of the composition and genetic diversity of the Obsoletus complex by partial sequencing of the cytochrome c oxidase I (cox1) gene in poorly studied areas of Spain. Methods A study of C. obsoletus populations was carried out using a single-tube multiplex polymerase chain reaction (PCR) assay that was designed to differentiate the Obsoletus complex sibling species Culicoides obsoletus and Culicoides scoticus, based on the partial amplification of the cox1 gene, as well as cox1 georeferenced sequences from Spain available at GenBank. We sampled 117 insects of the Obsoletus complex from six locations and used a total of 238 sequences of C. obsoletus (ss) individuals (sampled here, and from GenBank) from 14 sites in mainland Spain, the Balearic Islands and the Canary Islands for genetic diversity and phylogenetic analyses. Results We identified 90 C. obsoletus (ss), 19 Culicoides scoticus and five Culicoides montanus midges from the six collection sites sampled, and found that the genetic diversity of C. obsoletus (ss) were higher in mainland Spain than in the Canary Islands. The multiplex PCR had limitations in terms of specificity, and no cryptic species within the Obsoletus complex were identified. Conclusions Within the Obsoletus complex, C. obsoletus (ss) was the predominant species in the analyzed sites of mainland Spain. Information about the species composition of the Obsoletus complex could be of relevance for future epidemiological studies when specific aspects of the vector competence and capacity of each species have been identified. Our results indicate that the intraspecific divergence is higher in C. obsoletus (ss) northern populations, and demonstrate the isolation of C. obsoletus (ss) populations of the Canary Islands. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04841-z.
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Affiliation(s)
- Cecilia Aguilar-Vega
- Animal Health Department, Faculty of Veterinary Medicine, VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain.
| | - Belén Rivera
- Animal Health Department, Faculty of Veterinary Medicine, VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain
| | - Javier Lucientes
- Department of Animal Pathology (Animal Health), Faculty of Veterinary Medicine, AgriFood Institute of Aragón IA2, University of Zaragoza, Zaragoza, Spain
| | - Isabel Gutiérrez-Boada
- Animal Health Department, Faculty of Veterinary Medicine, VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain
| | - José Manuel Sánchez-Vizcaíno
- Animal Health Department, Faculty of Veterinary Medicine, VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain
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Bourquia M, Garros C, Rakotoarivony I, Gardès L, Huber K, Boukhari I, Delécolle JC, Baldet T, Mignotte A, Lhor Y, Khallaayoune K, Balenghien T. Update of the species checklist of Culicoides Latreille, 1809 biting midges (Diptera: Ceratopogonidae) of Morocco. Parasit Vectors 2019; 12:459. [PMID: 31551074 PMCID: PMC6757417 DOI: 10.1186/s13071-019-3720-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 09/14/2019] [Indexed: 11/10/2022] Open
Abstract
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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Affiliation(s)
- Maria Bourquia
- Institut Agronomique et Vétérinaire Hassan II, Unité Parasitologie et Maladies Parasitaires, 10100, Rabat, Morocco. .,ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France. .,Cirad, UMR ASTRE, 34398, Montpellier, France.
| | - Claire Garros
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.,Cirad, UMR ASTRE, 97490, Ste Clotilde, La Réunion, France
| | - Ignace Rakotoarivony
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.,Cirad, UMR ASTRE, 34398, Montpellier, France
| | - Laetitia Gardès
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.,Cirad, UMR ASTRE, 97170, Petit-Bourg, Guadeloupe, France
| | - Karine Huber
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France
| | - Intissar Boukhari
- Institut Agronomique et Vétérinaire Hassan II, Unité Parasitologie et Maladies Parasitaires, 10100, Rabat, Morocco
| | - Jean-Claude Delécolle
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg (IPPTS) EA7292, 3 rue Koeberlé, 67000, Strasbourg, France
| | - Thierry Baldet
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.,Cirad, UMR ASTRE, 34398, Montpellier, France
| | - Antoine Mignotte
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.,Cirad, UMR ASTRE, 34398, Montpellier, France
| | - Youssef Lhor
- Office National de Sécurité Sanitaire des Produits Alimentaires, Institut Agronomique et Vétérinaire, 10015, Rabat, Morocco
| | - Khalid Khallaayoune
- Institut Agronomique et Vétérinaire Hassan II, Unité Parasitologie et Maladies Parasitaires, 10100, Rabat, Morocco
| | - Thomas Balenghien
- ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France. .,Cirad, UMR ASTRE, 34398, Montpellier, France. .,Institut Agronomique et Vétérinaire Hassan II, Unité Microbiologie, Immunologie et Maladies Contagieuses, 10100, Rabat, Morocco.
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Augot D, Mathieu B, Hadj-Henni L, Barriel V, Zapata Mena S, Smolis S, Slama D, Randrianambinintsoa FJ, Trueba G, Kaltenbach M, Rahola N, Depaquit J. Molecular phylogeny of 42 species of Culicoides (Diptera, Ceratopogonidae) from three continents. ACTA ACUST UNITED AC 2017. [PMID: 28643630 PMCID: PMC5482051 DOI: 10.1051/parasite/2017020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The genus Culicoides includes vectors of important animal diseases such as bluetongue and Schmallenberg virus (BTV and SBV). This genus includes 1300 species classified in 32 subgenera and 38 unclassified species. However, the phylogenetic relationships between different subgenera of Culicoides have never been studied. Phylogenetic analyses of 42 species belonging to 12 subgenera and 8 ungrouped species of genus Culicoides from Ecuador, France, Gabon, Madagascar and Tunisia were carried out using two molecular markers (28S rDNA D1 and D2 domains and COI mtDNA). Sequences were subjected to non-probabilistic (maximum parsimony) and probabilistic (Bayesian inference (BI)) approaches. The subgenera Monoculicoides, Culicoides, Haematomyidium, Hoffmania, Remmia and Avaritia (including the main vectors of bluetongue disease) were monophyletic, whereas the subgenus Oecacta was paraphyletic. Our study validates the subgenus Remmia (= Schultzei group) as a valid subgenus, outside of the subgenus Oecacta. In Europe, Culicoides obsoletus, Culicoides scoticus and Culicoides chiopterus should be part of the Obsoletus complex whereas Culicoides dewulfi should be excluded from this complex. Our study suggests that the current Culicoides classification needs to be revisited with modern tools.
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Affiliation(s)
- Denis Augot
- USC Vecpar, ANSES-LSA, Université de Reims Champagne-Ardenne, SFR Cap Santé, Faculté de Pharmacie, 51 rue Cognacq-Jay, EA 4688, Reims 51096, France
| | - Bruno Mathieu
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg, Université de Strasbourg, Faculté de Médecine, 3 rue Koeberlé, EA7292, Strasbourg 67000, France
| | - Leila Hadj-Henni
- USC Vecpar, ANSES-LSA, Université de Reims Champagne-Ardenne, SFR Cap Santé, Faculté de Pharmacie, 51 rue Cognacq-Jay, EA 4688, Reims 51096, France
| | - Véronique Barriel
- Muséum National d'Histoire Naturelle, CR2P-UMR 7207 CNRS, MNHN, UPMC, 8 rue Buffon, CP 38, 75005 Paris, France
| | - Sonia Zapata Mena
- Instituto de Microbiologia, Colegio de Ciencias Biologicas y Ambientales, Universidad San Francisco de Quito, Cumbayá, EC170157 Quito, Pichincha, Ecuador
| | - Sylvia Smolis
- USC Vecpar, ANSES-LSA, Université de Reims Champagne-Ardenne, SFR Cap Santé, Faculté de Pharmacie, 51 rue Cognacq-Jay, EA 4688, Reims 51096, France
| | - Darine Slama
- Laboratory of Medical and Molecular Parasitology-Mycology, Faculty of Pharmacy, University of Monastir, 99UR/08-05, 5000 Monastir, Tunisia
| | | | - Gabriel Trueba
- Instituto de Microbiologia, Colegio de Ciencias Biologicas y Ambientales, Universidad San Francisco de Quito, Cumbayá, EC170157 Quito, Pichincha, Ecuador
| | - Matthieu Kaltenbach
- Laboratoire de Pharmacologie, Université de Reims Champagne-Ardenne, UFR Pharmacie, 51 rue Cognacq-Jay, 51100 Reims, France
| | - Nil Rahola
- Unité MIVEGEC, UMR 224-5290 IRD-CNRS-UM, Centre IRD de Montpellier, BP 64501, 911 avenue Agropolis, 34394 Montpellier, France - Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon
| | - Jérôme Depaquit
- USC Vecpar, ANSES-LSA, Université de Reims Champagne-Ardenne, SFR Cap Santé, Faculté de Pharmacie, 51 rue Cognacq-Jay, EA 4688, Reims 51096, France
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Sarvašová A, Kočišová A, Candolfi E, Mathieu B. Description of Culicoides (Culicoides) bysta n. sp., a new member of the Pulicaris group (Diptera: Ceratopogonidae) from Slovakia. Parasit Vectors 2017; 10:279. [PMID: 28578677 PMCID: PMC5457568 DOI: 10.1186/s13071-017-2195-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 05/12/2017] [Indexed: 11/22/2022] Open
Abstract
Background Species of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) are mainly known as vectors of arboviruses such as bluetongue (BTV) and Schmallenberg (SBV). Among the known vectors, few species within the subgenus Culicoides Latreille, 1809 have been implicated in the transmission of BTV and SBV. Nevertheless, phylogenetic studies had revealed the presence of cryptic and undescribed species in Europe, raising questions about their vectorial role. A previous integrative study, associating morphology and barcode data, raised the hypothesis of the presence of undescribed species in Slovakia. The present study, combining morphological and molecular approaches, is aimed to support the hypothesis and a description of Culicoides bysta n. sp. is provided. Methods Series of male and female specimens were dissected and several of them were sequenced for the barcode region of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Bayesian inference phylogenetic analyses based on 72 cox1 sequences of the species belonging to the Pulicaris group of the subgenus Culicoides, were carried out and the frequencies of intra/interspecific variations were analyzed. The morphology of abundant material of the new species (31 females and 12 males) was examined and compared with the paratypes of Culicoides boyi Nielsen, Kristensen & Pape, 2015 and with specimens of Culicoides pulicaris Linnaeus, 1758. For females, suture distances on the eyes were newly evaluated as a diagnostic character and for males we assessed a new measurement on the ninth tergite and on the apicolateral processes. Results Both phylogenetic analysis and barcode distances supported the distinct status of the new species, Culicoides bysta n. sp. described as a member of the Pulicaris group based on the morphology of males and females. The new species is closely related to C. boyi and C. pulicaris but can be distinguished on the basis of the wing pattern and the ratio between the two eye sutures. Both newly evaluated characters, i.e. eyes in females and male genitalia appeared to be diagnostic for distinguishing the new species described herein. Conclusions The vector potential of the recently described species C. boyi and C. bysta n. sp. to transmit arboviruses, such as BTV and SBV, is unknown. When considering these two species as being close to C. pulicaris, the previous data, such as the vector implication for C. pulicaris in BTV transmission, should be revaluated in future.
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Affiliation(s)
- Adela Sarvašová
- Department of Parasitology, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, SK-04181, Košice, Slovak Republic
| | - Alica Kočišová
- Department of Parasitology, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, SK-04181, Košice, Slovak Republic.
| | - Ermanno Candolfi
- Medicine Faculty, Institute of Parasitology and Tropical Pathology (IPPTS), EA7292, 3 rue Koeberlé, F-67000, Strasbourg, France.,Laboratoire de Parasitologie et de Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, F-67000, Strasbourg, France
| | - Bruno Mathieu
- Medicine Faculty, Institute of Parasitology and Tropical Pathology (IPPTS), EA7292, 3 rue Koeberlé, F-67000, Strasbourg, France
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Harrup LE, Bellis GA, Balenghien T, Garros C. Culicoides Latreille (Diptera: Ceratopogonidae) taxonomy: current challenges and future directions. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 30:249-266. [PMID: 25535946 PMCID: PMC4330985 DOI: 10.1016/j.meegid.2014.12.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 11/23/2022]
Abstract
Culicoides Latreille biting midges (Diptera: Ceratopogonidae) cause a significant biting nuisance to humans, livestock and equines, and are the biological vectors of a range of internationally important pathogens of both veterinary and medical importance. Despite their economic significance, the delimitation and identification of species and evolutionary relationships between species within this genus remains at best problematic. To date no phylogenetic study has attempted to validate the subgeneric classification of the genus and the monophyly of many of the subgenera remains doubtful. Many informal species groupings are also known to exist but few are adequately described, further complicating accurate identification. Recent contributions to Culicoides taxonomy at the species level have revealed a high correlation between morphological and molecular analyses although molecular analyses are revealing the existence of cryptic species. This review considers the methods for studying the systematics of Culicoides using both morphological and genetic techniques, with a view to understanding the factors limiting our current understanding of Culicoides biology and hence arbovirus epidemiology. In addition, we examine the global status of Culicoides identification, highlighting areas that are poorly addressed, including the potential implementation of emerging technologies.
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Affiliation(s)
- L E Harrup
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK.
| | - G A Bellis
- University of Queensland, St Lucia, Brisbane, Qld, Australia
| | - T Balenghien
- Cirad, UMR15 CMAEE, 34398 Montpellier, France; INRA, UMR1309 CMAEE, 34398 Montpellier, France
| | - C Garros
- Cirad, UMR15 CMAEE, 34398 Montpellier, France; INRA, UMR1309 CMAEE, 34398 Montpellier, France
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Culicoides (Avaritia) gornostaevae Mirzaeva, 1984 (Diptera: Ceratopogonidae)--a possible vector species of the Obsoletus group new to the European fauna. Parasit Vectors 2014; 7:445. [PMID: 25270724 PMCID: PMC4262083 DOI: 10.1186/1756-3305-7-445] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Culicoides gornostaevae Mirzaeva, 1984, known previously only from Siberia, is a boreal species included into the Obsoletus group of Culicoides sg. Avaritia. Members of the subgenus can act as vectors of various diseases. In Europe they are involved in the transmission of the Schmallenberg virus and bluetongue virus. FINDINGS Culicoides gornostaevae Mirzaeva, 1984 is reported for the first time in Europe with new country records from Norway, Poland and Sweden. CONCLUSIONS Culicoides gornostaevae Mirzaeva, 1984 has not been previously mentioned from Europe, even though there has been an extensive monitoring of Culicoides species during the last decades. Most probably this species has been notoriously overlooked in the materials, because of the problems with identification of the females of the subgenus Avaritia. Similar to other species of the Obsoletus group, C. gornostaevae should be regarded as a possible vector for Schmallenberg and bluetongue virus.
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Thompson GM, Jess S, Gordon AW, Murchie AK. Sticky-trapping biting midges (Culicoides spp.) alighting on cattle and sheep: effects of trap colour and evidence for host preference. Parasitol Res 2014; 113:3085-94. [DOI: 10.1007/s00436-014-3974-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/25/2014] [Indexed: 11/28/2022]
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Garros C, Balenghien T, Carpenter S, Delécolle JC, Meiswinkel R, Pédarrieu A, Rakotoarivony I, Gardès L, Golding N, Barber J, Miranda M, Borràs DB, Goffredo M, Monaco F, Pagès N, Sghaier S, Hammami S, Calvo JH, Lucientes J, Geysen D, De Deken G, Sarto I Monteys V, Schwenkenbecher J, Kampen H, Hoffmann B, Lehmann K, Werner D, Baldet T, Lancelot R, Cêtre-Sossah C. 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; 7:223. [PMID: 24884950 PMCID: PMC4024274 DOI: 10.1186/1756-3305-7-223] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/28/2014] [Indexed: 01/11/2023] Open
Abstract
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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Mathieu B, Delecolle JC, Garros C, Balenghien T, Setier-Rio ML, Candolfi E, Cêtre-Sossah C. 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; 182:297-306. [PMID: 21715095 DOI: 10.1016/j.vetpar.2011.05.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/23/2011] [Accepted: 05/30/2011] [Indexed: 10/18/2022]
Abstract
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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Affiliation(s)
- Bruno Mathieu
- Institut de Parasitologie et de Pathologie Tropicale, Université de Strasbourg, EA 4438, 67000 Strasbourg, France
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Nielsen SA, Kristensen M. Morphological and molecular identification of species of the Obsoletus group (Diptera: Ceratopogonidae) in Scandinavia. Parasitol Res 2011; 109:1133-41. [PMID: 21461726 DOI: 10.1007/s00436-011-2357-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 03/16/2011] [Indexed: 11/28/2022]
Abstract
After the introduction of bluetongue in northern Europe in 2006, populations of Culicoides have been monitored in many European countries. Large quantities of Culicoides specimens shall be determined to species, and it is thus important to find reliable morphological characters that are visualized in a stereomicroscope. Culicoides obsoletus, Culicoides scoticus, Culicoides chiopterus, and Culicoides dewulfi all belonging to subgenus Avaritia are common in collections in northern Europe. C. obsoletus and C. scoticus often make up more than 50% of the total catch of biting midges. Separation of the females of the four species by morphological characters has frequently been questioned, and in many cases, female specimens are grouped as an entity in veterinary and ecological studies. We show how it is possible using a stereomicroscope to separate the females of the four species by combining the shape of the third segment of the maxillary palp and the number and location of hairs on the first abdominal tergit. Validation of the quick stereomicroscope identification method was achieved by morphometric measurements and a molecular marker. In all cases, both methods verified the quick morphological species identification of the Obsoletus group females. In conclusion, the females of all four species of the Obsoletus group can be separated by a quick morphological method under the stereomicroscope.
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Affiliation(s)
- Søren Achim Nielsen
- Department of Environmental, Social and Spatial Change, Roskilde University, Building 18.1, 4000 Roskilde, Denmark.
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