Transfluthrin enhances odorant receptor-mediated spatial repellency in Aedes aegypti

Andreazza, Felipe; Valbon, Wilson Rodrigues; Dong, Ke

doi:10.1016/j.pestbp.2023.105387

Cited by 8 publications

(11 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compared with other compounds that were recently tested against Rockefeller mosquitoes in the hand-in-cage assay, the potency of PFTE in eliciting spatial repellency is comparable to those of plant-derived compounds, but lower than those of DEET and volatile pyrethroids. − For instance, eucalyptol and camphor elicited 50–60% repellency at 100 ppm. Geranyl acetate elicited about 70–80% repellency at 100 ppm. , PFTE is only slightly more potent than pyrethrin I and II which elicited 50–60% repellency at 1000 ppm . On the other hand, DEET, transfluthrin, and bioallethrin elicited ∼50% of mosquito repellency at 1–10 ppm. , …”

Section: Resultsmentioning

confidence: 95%

“…Interestingly, racemic 1a always crystallized as conglomerates 34 (a mixture of homochiral enantiomer crystals) in the P2 1 space group from solution or from melts (Figure 4A). In contrast, other racemates displayed in Figure 3 all crystallized as racemates 47 (equimolar amounts of enantiomers in the crystal lattices; Figure 4B and Figure S2). Since the crystals in conglomerates of 1a were tiny needles (<100 μm), the separation of enantiomer crystals based on crystal morphology (a Pasteur-like resolution) was not feasible.…”

Section: Acs Infectious Diseasesmentioning

confidence: 99%

“…46 On the other hand, DEET, transfluthrin, and bioallethrin elicited ∼50% of mosquito repellency at 1−10 ppm. 47,49 Rat Oral Toxicity. Compounds 1a and 1b were chosen for mammalian oral toxicity screening because their structures and lethality were similar to, and representative of, other compounds identified in Figure 3A.…”

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Insecticidal and Repellent Properties of Rapid-Acting Fluorine-Containing Compounds against Aedes aegypti Mosquitoes

et al. 2023

Self Cite

View full text Add to dashboard Cite

The development of safe and potent insecticides remains an integral part of a multifaceted strategy to effectively control human-disease-transmitting insect vectors. Incorporating fluorine can dramatically alter the physiochemical properties and bioavailability of insecticides. For example, 1,1,1-trichloro-2,2-bis(4-fluorophenyl)ethane (DFDT)a difluoro congener of trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)was demonstrated previously to be 10-fold less toxic to mosquitoes than DDT in terms of LD50 values, but it exhibited a 4-fold faster knockdown. Described herein is the discovery of fluorine-containing 1-aryl-2,2,2-trichloro-ethan-1-ols (FTEs, for fluorophenyl-trichloromethyl-ethanols). FTEs, particularly per-fluorophenyl-trichloromethyl-ethanol (PFTE), exhibited rapid knockdown not only against Drosophila melanogaster but also against susceptible and resistant Aedes aegypti mosquitoes, major vectors of Dengue, Zika, yellow fever, and Chikungunya viruses. The R enantiomer of any chiral FTE, synthesized enantioselectively, exhibited faster knockdown than its corresponding S enantiomer. PFTE does not prolong the opening of mosquito sodium channels that are characteristic of the action of DDT and pyrethroid insecticides. In addition, pyrethroid/DDT-resistant Ae. aegypti strains having enhanced P450-mediated detoxification and/or carrying sodium channel mutations that confer knockdown resistance were not cross-resistant to PFTE. These results indicate a mechanism of PFTE insecticidal action distinct from that of pyrethroids or DDT. Furthermore, PFTE elicited spatial repellency at concentrations as low as 10 ppm in a hand-in-cage assay. PFTE and MFTE were found to possess low mammalian toxicity. These results suggest the substantial potential of FTEs as a new class of compounds for controlling insect vectors, including pyrethroid/DDT-resistant mosquitoes. Further investigations of FTE insecticidal and repellency mechanisms could provide important insights into how incorporation of fluorine influences the rapid lethality and mosquito sensing.

show abstract

Section: Resultsmentioning

confidence: 95%

Section: Acs Infectious Diseasesmentioning

confidence: 99%

See 1 more Smart Citation

Insecticidal and Repellent Properties of Rapid-Acting Fluorine-Containing Compounds against Aedes aegypti Mosquitoes

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…This is presumably because mosquitoes will spend more time in close contact to the host while locating a suitable site to bite, especially if their olfactory system has been disrupted, whereas the landing experiment mosquitoes were removed as soon as they landed on a host and placed into a paper cup, where they may have been less exposed to insecticide [22,23].…”

Section: Discussionmentioning

confidence: 99%

Evaluating human landing catches as a measure of mosquito biting and the importance of considering additional modes of action

Fairbanks,

Tambwe,

Moore

et al. 2024

Preprint

View full text Add to dashboard Cite

Entomological evaluations of vector control tools often use human landing catches (HLCs) as a standard measure of a direct human-vector contact. However, some tools have additional characteristics, such as mortality, and HLCS are not sensitive for measuring other effects beyond landing inhibition. Therefore, additional measures may need to be considered when evaluating these tools for public health use. This study has two main aims (1) the evaluate the accuracy of HLCs as a proxy for feeding and (2) to compare the predicted reduction in vectorial capacity when we do and do not consider these additional characteristics. To achieve this, we analyse previously published semi-field data from an experiment which used HLCs and another where mosquitoes were allowed to feed in the presence of different dosages of the volatile pyrethroid spatial repellent, transfluthrin. We compare results for two mathematical models: one which only considers the reduction in feeding effect and one which also considers mortality before and after feeding (using data gathered by the aspiration of mosquitoes after the semi-field feeding/landing period and 24 hour survival monitoring). These Bayesian hierarchical models are parameterised using Bayesian inference. We observe that, for susceptible mosquitoes, reduction in landing is underestimated by HLCs. For knockdown resistant mosquitoes the relationship is less clear; with HLCs sometimes appearing to overestimate this characteristic. We find HLCs tend to under-predict the relative reduction in vectorial capacity in susceptible mosquitoes while over-predicting this impact in knockdown-resistant mosquitoes. Models without secondary effects have lower predicted relative reductions in vectorial capacities. Overall, this study highlights the importance of considering additional characteristics to reduction in biting of volatile pyrethroid spatial repellents. We recommend that these are considered when evaluating novel vector control tools.

show abstract

“…For larger dosages of transfluthrin, more preprandial killing was observed in the feeding experiments. This is presumably because mosquitoes will spend more time in close contact to the host while locating a suitable site to bite, especially if their olfactory system has been disrupted, whereas the landing experiment mosquitoes were removed as soon as they landed on a host and placed into a paper cup, where they may have been less exposed to insecticide 22 , 23 . For postprandial mortality the estimates from the feeding and landing experiments more closely align when considering only mosquitoes that fed when offered a blood meal in the landing experiment.…”

Section: Discussionmentioning

confidence: 99%

Evaluating human landing catches as a measure of mosquito biting and the importance of considering additional modes of action

Fairbanks,

Tambwe,

Moore

et al. 2024

Sci Rep

View full text Add to dashboard Cite

Entomological evaluations of vector control tools often use human landing catches (HLCs) as a standard measure of a direct human-vector contact. However, some tools have additional characteristics, such as mortality, and HLCS are not sensitive for measuring other effects beyond landing inhibition. Therefore, additional measures may need to be considered when evaluating these tools for public health use. This study has two main aims (1) the evaluate the accuracy of HLCs as a proxy for feeding and (2) to compare the predicted reduction in vectorial capacity when we do and do not consider these additional characteristics. To achieve this, we analyse previously published semi-field data from an experiment which used HLCs and another where mosquitoes were allowed to feed in the presence of different dosages of the volatile pyrethroid spatial repellent, transfluthrin. We compare results for two mathematical models: one which only considers the reduction in feeding effect and one which also considers mortality before and after feeding (using data gathered by the aspiration of mosquitoes after the semi-field feeding/landing period and 24 h survival monitoring). These Bayesian hierarchical models are parameterised using Bayesian inference. We observe that, for susceptible mosquitoes, reduction in landing is underestimated by HLCs. For knockdown resistant mosquitoes the relationship is less clear; with HLCs sometimes appearing to overestimate this characteristic. We find HLCs tend to under-predict the relative reduction in vectorial capacity in susceptible mosquitoes while over-predicting this impact in knockdown-resistant mosquitoes. Models without secondary effects have lower predicted relative reductions in vectorial capacities. Overall, this study highlights the importance of considering additional characteristics to reduction in biting of volatile pyrethroid spatial repellents. We recommend that these are considered when evaluating novel vector control tools.

show abstract

Transfluthrin enhances odorant receptor-mediated spatial repellency in Aedes aegypti

Cited by 8 publications

References 32 publications

Insecticidal and Repellent Properties of Rapid-Acting Fluorine-Containing Compounds against Aedes aegypti Mosquitoes

Insecticidal and Repellent Properties of Rapid-Acting Fluorine-Containing Compounds against Aedes aegypti Mosquitoes

Evaluating human landing catches as a measure of mosquito biting and the importance of considering additional modes of action

Evaluating human landing catches as a measure of mosquito biting and the importance of considering additional modes of action

Contact Info

Product

Resources

About