Sergeia podlipaevi gen. nov., sp nov (Trypanosomatidae, Kinetoplastida), a parasite of biting midges (Ceratopogonidae, Diptera)

Three strains of a trypanosomatid protozoan were isolated from the midguts of two naturally infected species of biting midges [Culicoides (Oecacta) festivipennis and Culicoides (Oecacta) truncorum] and characterized by light and electron microscopy and by molecular techniques. Morphological characteristics and sequences of the 18S rRNA, 5S rRNA, spliced leader RNA and glycosomal g lyceraldehyde-3- phosphate clehydrogenase genes indicate that the studied flagellates represent a novel phylogenetic lineage within the Trypanosomaticlae. Based on phylogenetic analyses, the novel endosymbiont-free, monoxenous trypanosomatid was classified as Sergeia podlipaevi gen. nov., sp. nov. Interestingly, it is closely related to another trypanosomatid species that parasitizes the sand fly Lutzomyia evansi, a blood-sucking clipteran from South America. The type strain of S. podlipaevi sp. nov., ICUL/CZ/2000/CER3, was obtained from Malpighian tubes. Of 2518 females of seven species of biting midges trapped in the Czech Republic, more than 1.5 % were infected by trypanosomatid parasites. An unrelated insect species, Culicoides (Mono culicoides) nubeculosus, was experimentally infected with S. podlipaevi, demonstrating that its host range extends to different sulogenera of biting midges.