Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal

Maryam Diarra (1, 2) , Moussa Fall (3, 1) , Assane G. Fall (1) , Aliou Diop (2) , Momar Talla Seck (1) , Claire Garros (4) , Thomas Balenghien (4) , Xavier Allene (4) , Ignace Rakotoarivony (4) , Renaud Lancelot (4) , Iba Mall (1) , Mame Thierno Bakhoum (1) , Ange Michel Dosum (1) , Massouka Ndao (1) , Jérémy Bouyer (4, 1) , Hélène Guis (4)

1 Laboratoire National de l’Elevage et de Recherches Vétérinaires
2 Laboratoire d’Etudes et de Recherches en Statistiques et Développement
3 UCAD - Université Cheikh Anta Diop de Dakar [Sénégal]
4 UMR CMAEE - Contrôle des maladies animales exotiques et émergentes

Background: The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods: Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results: In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions: In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site.

Mots clés: Vector-borne disease; Spatial and temporal dynamics; Light traps; Arbovirus; Orbivirus; Equids

Mots clés: Insect vectors; Culicoides oxystoma; Culicoides imicola; Africa

Domaines: Sciences du Vivant [q-bio]

Maryam Diarra, Moussa Fall, Assane G. Fall, Aliou Diop, Momar Talla Seck, et al.. Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal. Parasites & Vectors, 2014, 7, ⟨10.1186/1756-3305-7-147⟩. ⟨hal-02631879⟩