Genetic characterization of a new entomo-pathogenic nematode (Tylenchida: Allantonematidae) parasite in wild-caught sandflies (Diptera: Psychodidae) from Western Ghats, India

Sandflies (Diptera: Psychodidae) are medically important insects prevalent in tropical and temperate regions of the world. About 30 species of these flies have been recorded from the Western Ghats region of Kerala. While carrying out epidemiological investigations on Leishmaniasis in this region, we found two species of field-collected sandflies viz., Phlebotomus argentipes and Sergentomyia monticola infected with Tylenchid nematode parasites. The infection rates were 0.89% and 0.9%, respectively. The parasite density of nematode juvenile stages was more than 1000 in all the specimens. Both males and females were found infected. We performed molecular characterization of these nematode parasites using multiple genetic markers, mitochondrial COI, and two different regions of 18S rDNA. The genetic analysis revealed that the nematode belonged to the genus Howardula of family Allantonematidae, one infesting P. argentipes (major vector species of Leishmania) and the other, S. monticola . This is the first report of natural infection with the entomo-parasitic nematode species, belonging to Allantonematidae among these sandfly species from India. Genetically related and unclassified species of nematodes belonging to this family had been reported elsewhere from termite species. As larval stages of sandflies develop in the organic matter of termite mounds, this finding may have significant implications on their bionomics and control. Graphical Abstract