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

Abstract

-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 ITS 1 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. molecular detection / Culicoides imicola / ITS1 / PCR / bluetongue

Phenotypic differentiation and phylogenetic signal of wing shape in western European biting midges, Culicoides spp., of the subgenus Avaritia

“…As correct identification of disease vectors is essential in transmission risk assessment, recent efforts have centred upon developing molecular and morphological tools that allow a reliable discrimination between similar species of the Obsoletus group (Cêtre-Sossah et al, 2004;Pagès & Sarto i Monteys, 2005;Mathieu et al, 2007;Nolan et al, 2007;Augot et al, 2010;Nielsen & Kristensen, 2011). In spite of the advantages of employing morphometrics in cryptic species identification and the widespread use of this methodological approach in other biological disciplines, few studies have attempted to discriminate between similar species of Culicoides using multivariate analysis of continuous traits (exceptions are Pagès et al, 2009;Augot et al, 2010).…”

A survey of biting midges of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) in NE Bulgaria, with respect to transmission of avian haemosporidians

“…Numerous studies (Dallas et al 2003;Li et al 2003;Cêtre-Sossah et al 2004;Wörheide et al 2004;Perrin et al 2006) dealing with a similar problem found the noncoding genetic region of the internal transcribed spacer 1 (ITS-1) of the mitochondrial ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 (COI) to be highly promising in order to establish a reliable polymerase chain reaction (PCR)-based method for species identification.…”

Changes of the abundance of Culicoides obsoletus s.s. and Culicoides scoticus in Southwest Germany identified by a PCR-based differentiation

“…Using highly specific and sensitive oligonucleotides based on the ITS1 ribosomal DNA sequences, C. imicola has been identified in mixed pools of several European Culicoides spp. (Cêtre-Sossah et al 2004). Sequencing the ITS1 rDNA of 32 species of Culicoides for a phylogenetic analysis, C obsoletus, C. scoticus, and C. imicola clustered together, clearly separated from C. nubeculosus, C. puncticollis, and C. variipennis, the latter being classified as members of the Obsoletus complex or as members of the subgenus Monoculicoides (Perrin et al 2006).…”

“…In ceratopogonids, sequences of the nuclear internal transcribed spacer (ITS) or the mitochondrial cytochrome oxidase subunit I (COI) have been used (Cêtre-Sossah et al 2004;Meiswinkel et al 2004;Pages and Sarto i Monteys 2005;Nolan et al 2007). In the present investigation, we used oligonucleotides suggested to be specific for COI of two species of the Obsoletus complex, Culicoides obsolteus s.s., and C. scoticus (Pages and Sarto i Monteys 2005).…”