Ground ultra low volume (ULV) space spray applications for the control of wild sand fly populations (Psychodidae: Phlebotominae) in Europe

Authors: CHASKOPOULOU, ALEXANDRA - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL); KASHEFI - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL); MIAOULIS, MICHAIL - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL)

Submitted to: ACTA TROPICA
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2018
Publication Date: 6/1/2018
Citation: Chaskopoulou, A., Kashefi, Miaoulis, M. 2018. Ground ultra low volume (ULV) space spray applications for the control of wild sand fly populations (Psychodidae: Phlebotominae) in Europe. ACTA TROPICA. 182:54-59. doi: 10.1016/j.actatropica.2018.02.003.
DOI: https://doi.org/10.1016/j.actatropica.2018.02.003

Interpretive Summary: Sand fly species of the genera Phlebotomus (Old World) and Lutzomyia (New World) are responsible for the transmission of Leishmania parasitic protozoans. Even though leishmaniasis is not common in the United States (occasional cases have been acquired in Oklahoma and Texas), the disease constitutes a major threat to the US military during their overseas operations. Current measures for sand fly control include mostly indoor interventions to target endophilic sand fly species with very limited number of vector control tools for outdoor interventions. Research is required to develop additional tools to control sand flies in outdoors settings in order to more effectively mitigate the risk of leishmania transmission. In this study we investigated a) sand fly behavior (flight activity patterns, flight height preference) within candidate treatment sites in order to optimize the timing and application parameters of outdoor space spray ultra low volume (ULV) treatments, and b) the efficacy of properly timed ground ULV applications of a deltamethrin-based product against field populations of major nuisance and pathogen-transmitting sand flies of the Mediterranean Basin. Aqua-K-Othrine is a water-based formulation of deltamethrin available for mosquito adulticiding in European Union (EU) countries. The same product is registered in the USA with the commercial name Deltaguard. However, this product has not been tested in ground applications against Phlebotomine sand flies. Exposure of the sand flies to the treatments resulted in substantial reduction of their populations. This research will contribute significantly in the optimization of ULV space sprays against wild sand fly populations.

Technical Abstract: Phlebotomus sand flies are considered to be important vectors of both canine and human leishmaniasis. Current measures for sand fly control include mostly indoor interventions, such as residual spraying of dwellings (IRS) to target endophilic sand fly species, and a very limited number of vector control tools for outdoor interventions against exophilic sand flies. In this study we investigated the efficacy of ground ultra low volume (ULV) space spray applications of a deltamethrin based product against field populations of P. perfiliewi, a major nuisance and pathogen-transmitting sand fly species of the Mediterranean Basin. Sand fly flight activity patterns and flight height preference within candidate treatment sites (kennels) were determined prior to treatments in order to optimize the timing and application parameters of the spray applications. On average there was a distinct activity peak between 20.00 – 22.00 h for both male and female P. perfiliewi, with more than 45% and 30% of the population sampled occurring between 20.00-21.00 h and 21.00-22.00 h, respectively. No significant difference was observed in sand fly numbers from sticky traps placed at 0.5 up to 1.5 m height. However, there was a significant decrease in sand fly numbers at 2 m indicating a preference of sand flies to fly below 2 m. The low and high application rate of deltamethrin resulted in a decrease of 18 and 66%, respectively, of the sand fly population between pre-and post-treatment trap nights. In contrast, the population in the untreated control area increased 30 % between pre- and post-treatment nights. The results of this study provide strong evidence that ground ULV space spray applications when applied properly can result in significant sand fly control levels, even in a heavily infested sand fly environment such as the kennel sites used in this study.