![]() ![]() This has gained wide acceptance as a supplementary method to resolve taxonomic ambiguities. DNA barcoding for species-level identification employs a small portion (≈ 658 bp) of the cox1 gene to assign a specimen sequence to a voucher species library. proposed using the mitochondrial gene cytochrome c oxidase subunit 1 ( cox1) as a DNA-based identification system for all animal species, the so-called DNA barcoding approach. Although molecular tools may be expensive and require specialized equipment, they have been useful over the last decade to deepen knowledge in various areas of biology ranging from systematics to ecology. Inaccurate Culicoides species identification can have significant impacts on control attempts.Ĭonsidering these difficulties, it is essential to use complementary and alternative methods to solve taxonomic problems such as the identification of Culicoides larvae. Taking into account that subadult stages of the majority of Culicoides species still await discovery, morphological species identification of Culicoides larvae is not possible. Adult morphological identification may involve dissection and microscopical mounting of specimens. However, a major limitation is that morphology-based methods for Culicoides species identification are time-consuming and require taxonomic expertise. Knowledge on the ecology of Culicoides will be crucial for the development and implementation of appropriate and effective vector control strategies in order to reduce the impact of Culicoides-borne diseases. Massive AHS epizootic outbreaks occurred in Senegal in 2007. This disease is recorded in Africa and Arabian Peninsula and is ranked among the most lethal of viral infections known to affect horses with mortality rates in naive equine populations that can reach 80–90%. African horse sickness virus is an arbovirus of equids that is biologically transmitted by competent vectors of the genus Culicoides. Certain Culicoides species are the biological vectors of important arboviruses of livestock worldwide, such as the African horse sickness virus (AHSV), bluetongue virus (BTV), epizootic hemorrhagic disease virus (EHDV), equine encephalosis virus (EEV) and Schmallenberg virus (SBV). Such a diagnostic tool offers great opportunities for investigating Culicoides immature stages ecology and biology, a prerequisite for the implementation of eco-epidemiological studies to better control AHSV in the Niayes region of Senegal, and more generally in sub-Saharan Africa.īiting midge species of the genus Culicoides Latreille (Diptera: Ceratopogonidae) comprise more than 1300 species distributed worldwide. Our study proves the efficiency of DNA barcoding for studying Culicoides larval diversity in field samples. A total of 1131 cox1 sequences of adult and larval Culicoides were analyzed, and a hierarchical increase in mean divergence was observed according to two taxonomic levels: within species (mean = 1.92%, SE = 0.00), and within genus (mean = 17.82%, SE = 0.00). Of the 933 cox1 sequences of Culicoides larvae analyzed, 906 were correctly identified by their barcode sequences corresponding to eight species of Culicoides. ResultsĪ database of 230 cox1 sequences belonging to 42 Afrotropical Culicoides species was found to be reliable for species-level assignments, which enabled us to identify cox1 sequences of Culicoides larvae from the Niayes area of Senegal. In this study, our objectives were as follows: (i) establish a reference DNA barcode for Afrotropical Culicoides species (ii) assess the accuracy of cox1 in identifying Afrotropical Culicoides species and (iii) test the applicability of DNA barcoding for species identification on a large number of samples of Culicoides larvae from the Niayes area of Senegal, West Africa. DNA barcoding based on the mitochondrial gene cytochrome c oxidase subunit 1 ( cox1) is used as a rapid and authentic tool for species identification in a wide variety of animal taxa across the globe. However, morphology-based identification has limitations and warrants integration of molecular data. The ecological and veterinary interest of Culicoides emphasizes the need for rapid and reliable identification of vector species. ![]() Several species of Culicoides are vectors of various viruses that can affect animals, like the African horse sickness virus (AHSV), known to be endemic in sub-Saharan Africa. Biting midge species of the genus Culicoides Latreille (Diptera: Ceratopogonidae) comprise more than 1300 species distributed worldwide. ![]()
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