Detection by PCR of Culicoides insignis Lutz (Diptera: Ceratopogonidae), the main vector of bluetongue virus (BTV) in the Neotropical region

MAHIA MARIEL AYALA; FLORENTINA DIAZ; MICIELI MARIA VICTORIA; SPINELLI, GUSTAVO RICARDO; MARÍA MARCELA RONDEROS

La Plata

Congreso; II Congress of Latin American Society for Vector Ecology; 2022

LASOVE (Latin American Society of Vector Ecology)

Bluetongue Virus (BTV) cause a viral, non contagiosus disease that mainly affects sheep,cattle and wild and farmed ruminants causing damage to these animals and significanteconomic losses. It is well known in Central America and the Caribbean, and even in theLesser Antilles, and in South America this virus has been isolated in Brazil, Argentina, Peru,Ecuador and Guyana. Culicoides insignis Lutz, the major BTV vector in South America, isone of the most frequent and abundant species found in Southeastern USA, the CaribbeanBasin, and Central and South America, that is primarily associated with cattle farms.Accurate identification of biting midges is essential for the understanding of diseaseepidemiology and vector control. Morphologically, Culicoides insignis is placed in theCulicoides guttatus group, the females are easily recognized from congeners of this speciesgroup by a combination of three wing characters: the r-m crossvein is distinctly dark, the veinR3 is dark up to the point where it turns abruptly forward to meet the costa, and by the singledistal pale spot in cell M1; other useful characters are the third palpal segment bearing anirregular sensory pit and the distal sensilla coeloconica always present on flagellomeres 1, 3,5, 7 and 9-13, and sometimes present on flagellomeres 2, 4, 6 and 8. The male wingfrequently exhibits a second pale spot at wing margin in cell M1. In the other hand, themolecular tools applied to taxonomy provide rapid and efficient method to the identification ofvector species. We designed a forward primer since a specific sequence of the ITS-1 regionof C. insignis, which does not generate amplification products in the other analyzedCulicoides species. To test the specificity of the primer in vitro we worked with the five most abundant species captured during the fieldwork in Misiones province. Later, because of thelack of ITS-1 sequences in the species of the guttatus group or some sequence of anyneotropical Culicoides in the database, the primer in sílico specificity was checked throughalignment with other Culicoides sequences published in GenBank with the aid of the onlineBLAST tool, where the alignment was carried out according to the parameters established bydefault of the program. The use of molecular biology tools applied to the specificidentification of species can simplify the taxonomic identification process of Culicoidesmidges and will contribute significantly in the case of cryptic species. With a specificity of100%, this method could also be used for larval identification and epidemiologicalsurveillance of these species.