First detection of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in Culicoides spp. (Diptera: Ceratopogonidae).

Background: Culicoides (Diptera: Ceratopogonidae) species are known to be the vectors of Bluetongue virus and African Horses Sickness virus (AHSV) in different areas of the world. Nevertheless, other researchers have hypothesized that these arthropods could be involved in the transmission of other pathogens such as Schmallenberg virus, Plasmodium and Leishmania parasites. Identification of the Culicoides' potential vector competence is crucial in understanding the worldwide Culicoides/Leishmania life cycle.

Findings: Blood fed and parous females of biting midges Culicoides spp. were collected between 2009 and 2010 in Central Tunisia. DNA was extracted from individual blood fed Culicoides and used as a template in a genus-specific PCR. Leishmania DNA was detected in 14 Culicoides imicola specimens and one Culicoides circumscriptus. In a second step, parasite identification was performed based on a single copy Topo-isomerase II gene specific amplification and sequencing. Leishmania infantum was identified in two infected Culicoides spp.

Conclusion: This is the first report of Leishmania DNA detection from naturally infected wild caught Culicoides spp. Our finding supports the assumption that Culicoides spp. are a potential vector for L. infantum.