Can piperonyl butoxide enhance the efficacy of pyrethroids against pyrethroid‐resistant Aedes aegypti?

Abstract

Summarybackground Pyrethroid resistance can be considered the main threat to the continued control of many mosquito vectors of disease. Piperonyl butoxide (PBO) has been used as a synergist to help increase the efficacy of certain insecticides. This enhancement stems from its ability to inhibit two major metabolic enzyme systems, P450s and non-specific esterases, and to enhance cuticular penetration of the insecticide.objective To compare the mortality of a characterized resistant Aedes aegypti strain, Nha Trang, from Vietnam and the susceptible laboratory strain Bora Bora on netting with the pyrethroid deltamethrin (DM) alone and in combination with PBO.methods Resistance mechanisms were characterized using molecular and bioassay techniques; standard PCR was used to test for the kdr target site mutation. Potential genes conferring metabolic resistance to DM were identified with microarray analysis using the Ae. aegypti 'detox chip'. These data were analysed alongside results from WHO susceptibility tests. P450, CYP9J32, was significantly overexpressed in the DM-resistant strain compared with the susceptible Bora Bora strain. Another five genes involved with oxidative stress responses in mosquitoes were also significantly overexpressed. The Nha Trang strain was homozygous for two kdr mutations. WHO cone bioassays were used to investigate mortality with incorporated DM-treated nets with and without PBO. PBO used in combination with DM resulted in higher mortality than DM alone.conclusion Synergists may have an important role to play in the future design of vector control products in an era when alternatives to pyrethroids are scarce.

Characterization of metabolic detoxifying enzymes in an insecticide resistant strain of <i>Aedes aegypti</i> harboring homozygous S989P and V1016G <i>kdr</i> mutations

“…A study in Vietnam reported that pyrethroid resistance in Ae. aegypti was conferred by V1016I mutations and cytochrome P450s; adding PBO enhanced the efficacy of pyrethroids (Bingham et al, 2011). In Malaysia, although kdr mutations (V1016G and F1534C) were present in Ae.…”

“…In Latin America, F1534C and V1016I, a valine to isoleucine transversion in domain II, are prevalent (Saavedra- Rodriguez et al, 2007;Harris et al, 2010). The V1016I mutation has also been reported from Vietnam, but has not been detected in Thailand (Bingham et al, 2011). Interestingly, the V1016G mutation is often found with a serine to proline mutation (S989P) in domain II (Stenhouse et al, 2013;Kawada et al, 2014).…”

Piperonyl Butoxide: An Enhancing Arsenal for an Adomant Foe

“…The incorporation of a Synergistic effect of Piperonyl Butoxide (PBO) on roof and side panels of LLINs have improved the efficacy of LLINs against resistant mosquitoes [19][20][21][22]. It has a potency of increasing cuticular penetration of insecticides and increase mosquito susceptibility [23].…”

“…Currently, LLINs have an improved synergistic effect of PBO on top or on top and all side panels for managemenet of insecticide resistance [20,22].…”

Sex-, tissue-, and exposure duration-dependent effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part I: oxidative and neurotoxic potentials

“…Modulators such as piperonyl butoxide (PBO) and menadione (MEN) are very useful to understand how biotransformation affects the toxicity of a chemical under investigation (20,21). PBO (IUPAC name: 5-[2-(2-butoxyethoxy) ethoxymethyl]-6-propyl-1,3-benzodioxole; CAS no: 51-03-6) is a methylenedioxyphenyl compound used to enhance the potency of certain pesticides by inhibiting CYP450s and esterases (22)(23)(24). As Tomizawa and Casida (5) stated in their review that PBO synergized with IMI in toxicity to insects, we wondered what would be the toxicity (oxidative stress and cholinesterase activity) of this combination in mammals.…”