Broadening the tools for recognizing sand fly breeding habitats: A novel molecular approach for the detection of Phlebotomine larval DNA in soil substrates

Authors: GIANTSIS, I - Aristotle University Of Thessaloniki; CHASKOPOULOU, ALEXANDRA - European Biological Control Laboratory (EBCL)

Submitted to: ACTA TROPICA
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2018
Publication Date: 11/13/2018
Citation: Giantsis, I.A., Chaskopoulou, A. 2018. Broadening the tools for recognizing sand fly breeding habitats: A novel molecular approach for the detection of Phlebotomine larval DNA in soil substrates. ACTA TROPICA. 190:123-128. https://doi.org/10.1016/j.actatropica.2018.11.008.
DOI: https://doi.org/10.1016/j.actatropica.2018.11.008

Interpretive Summary: Sandflies constitute a medically important group of insects due to the transmission of several pathogens in human and domestic animals. While for most insect pests, control of the immature stages is an important part of their management, present information is inadequate to facilitate this strategy for the control of sand fly populations. On account of this limited available knowledge regarding the ecology of the larvae of Phlebotomine sand flies, current vector control techniques are predominantly focused on controlling adult stages. Notably, in US Air Force Public Health Information and Resources report for sand flies is stated “Insecticide spraying of larval habitat is not possible because, usually, so little is known about where the larvae occur”. In this context, better understanding of larval ecology will result in designing more efficient and targeted control strategies against Phlebotomus species that constitute major Leishmania vectors. In this study we developed a novel molecular approach for the detection of sand fly breeding sites that can be used in the field to increase our knowledge on the ecology of the sand fly immature stages.

Technical Abstract: Phlebotomine sand flies constitute a group of haematophagous insects of great medical and veterinary importance. Despite the significant knowledge on the biology and behavior of adult sand flies in the wild, there is little information available on the ecology of their larval stages due to difficulties in locating their breeding habitats. So far, investigations on sand fly breeding sites were based on adult emerging methods or the direct examination of the soil for the presence of immatures. However, due to their minute size very few attempts were successful in detecting sand fly larvae from the field resulting in an important information gap on their breeding habits. To address this issue we developed a novel molecular approach for the detection of sand fly larval DNA within soil samples. Different larval numbers of Phlebotomus papatasi and P. tobbi species (alone and in combination), premixed with different volumes and types of soil substrates were identified and quantified with high sensitivity and specificity. Specifically, by modifying already existing soil DNA extraction protocols in combination with a real-time PCR using species-specific primers we successfully detected as low as one larva/40 ml of soil. This methodology may prove useful in increasing our knowledge on sand fly larval ecology in the field, and thus facilitate in designing more efficient and targeted control strategies against Phlebotomus sand flies.