Pyrethroid Insecticide Resistance Mechanisms in the AdultPhlebotomus papatasi(Diptera: Psychodidae)

Abstract

Phlebotomus papatasi is one of the most medically important sand fly species in the Old World, serving as a vector of Leishmania parasites and phleboviruses. Chemical control is still considered the most effective method for rapidly reducing populations of flying insects involved in vector-borne disease transmission, but is increasingly threatened by insecticide resistance in the target insect posing significant problems for entomologists responsible for control programs. This study was conducted to determine pyrethroid resistance mechanisms and the biological, physiological, and molecular impacts of resistance in Ph. papatasi, and to compare their resistance mechanisms against those reported for mosquitoes and other intensely studied dipterans. Field-collected Ph. papatasi from Aswan, Egypt, were subjected to sublethal doses of permethrin and reared as a resistant strain under laboratory conditions through 16 generations. Biological parameter observations of resistant Ph. papatasi revealed an association of resistance with productivity cost. Physiological analysis revealed that concentrations of oxidase and esterase enzymes increased in early generations of the resistant colony, and then subsided through the F16 generation to levels similar to those in a susceptible colony. The activity levels of acetylcholinesterase were higher in field-collected Ph. papatasi than in susceptible colony flies, but decreased significantly despite subsequent exposure to permethrin. The molecular search for gene mutations in the resistant strain of Ph. papatasi failed to identify any mutations common in pyrethroid-resistant mosquitoes. Our study revealed that the mechanism of pyrethroid resistance in sand flies is different than that in mosquitoes, at least at the genetic level.

Assessment of diagnostic doses for widely used synthetic pyrethroids (Deltamethrin & Permethrin) in an endemic focus of leishmaniasis in Turkey

“…The results of previous studies have shown that sand flies are less likely to develop resistance and are still susceptible to the majority of the available insecticides, which are actively in use [ 36 – 38 ]. Molecular approaches were also evaluated to test the pyrethroid resistance and failed to detect resistance among wild populations [ 39 ]. Our findings were similar to those previous insecticide susceptibility studies.…”

Sand Flies and Their Control Methods

“…Geçmişte vektör mücadelesi için oldukça yaygın kullanılan DDT'ye birçok bölgede kum sineklerinin direnç geliştirdiği bildirilmiştir (78). Sentetik piretroitlerle yapılan araştır-malarda ise özellikle sivrisineklerde gelişen piretroit direncinin, en az bir genetiksel yolla farklı şeklinde kum sineklerinde gelişti-ği yönündedir (79). Geçmişte kum sineklerine karşı kullanılmayan bazı ürünlere karşı kum sineklerinde gelişen direncin ise özellikle 6.…”

The Phlebotomus papatasi systemic transcriptional response to trypanosomatid-contaminated blood does not differ from the non-infected blood meal

“…However, elimination of leishmaniasis will likely require a combination of transmission blocking strategies and novel treatments. This is especially the case in light of reports of resistance to drugs used to treat human infections [3,4], as well as pesticides used to control vector populations [5][6][7]. But to develop approaches to blocking transmission, we need a better understanding of the basic biology that underlines the interactions between parasite and insect vector.…”