Evaluating the sterilizing effect of pyriproxyfen treated mosquito nets against Anopheles gambiae at different blood-feeding intervals

Jaffer, Aneesa; Protopopoff, Natacha; Mosha, Franklin W.; Malone, David; Rowland, Mark; Oxborough, Richard M.

doi:10.1016/j.actatropica.2015.07.011

“…Therefore, this concentration (666 mg/m 2 ) is recommended for residual spraying. This concentration is higher than the dose of 1% PPF (350 mg/m 2 ) that is normally used for coating nets, including commercially available treated nets (e.g., Olyset Duo ® , Sumitomo) [22,23,24,46,47]. Higher doses of PPF (≥ 1000 mg/m 2 ) have also been evaluated [18,35], however such doses may be too high and not economical for large scale use.…”

Section: Discussionmentioning

confidence: 99%

Pyriproxyfen-Treated Polypropylene Sheets and Resting Boxes for Controlling Mosquitoes in Livestock Operations

Khemrattrakool

¹

,

Yanola

²

,

Lumjuan

³

et al. 2019

Insects

View full text Add to dashboard Cite

Many insect vector species of medical and veterinary importance are found abundantly in areas where animals are held. In these areas, they often rest for a period of time on objects around the animals both before and after blood feeding. However, the use of neurotoxic insecticides for vector control is not advised for use in such shelters as these chemicals can pose hazards to animals. The present study evaluated the efficacy of pyriproxyfen (PPF), an insect growth regulator, applied to polypropylene sheets and resting boxes on the reproductivity of mosquitoes found in animal shelters in Chiang Mai, Thailand. The sheets sprayed with 666 mg PPF/m2 were set on the inner wall of a cowshed and kept in place for 3 h (6.00 to 9.00 pm). During this time, fully blood-fed female mosquitoes that landed and remained continuously on the sheets for 5, 10, and 20 min were collected. The results, involving Anopheles subpictus, An. vagus, Culex gelidus, Cx. tritaeniorhynchus, and Cx. vishnui, revealed significant reductions in oviposition rates, egg hatchability, pupation, and adult emergence in the PPF-treated groups compared to the control groups. Adult emergence rates were reduced to 85.6–94.9% and 95.5–100% in those exposed for 10 and 20 min, respectively. The sheets retained their effectiveness for three months. The PPF-treated (666 mg/m2) resting boxes (35 × 35 × 55 cm) were placed overnight at a chicken farm where Cx. quinquefasciatus predominated. Blood-fed mosquitoes were collected in the morning and reared in the laboratory. Oviposition rates were reduced by 71.7% and adult emergence was reduced by 97.8% compared to the controls. PPF residual spray on surface materials in animal sheds is a potential method for controlling mosquitoes. Further studies are needed to evaluate the impact of PPF-treated materials on wild populations.

show abstract

“…arabiensis, An. gambiae, Culex quinquefasciatus mosquito species [18,19,52]. This conserved phenomenon in different mosquito species suggests that PPF influences multiple steps in egg maturation and that the final reproductive outcome of PPF-treated female mosquitoes reflects the cumulative effects of PPF.…”

Section: Plos Neglected Tropical Diseasesmentioning

confidence: 94%

“…The inhibitory effect of PPF on mosquito reproduction is affected by the time of exposure, formulation, methods of application, and other abiotic factors [51][52][53]. In this study, we exposed adult mosquitoes to PPF by placing them into cartons that had a lining of PPF-treated cotton gauzes.…”

Section: Ppf Suppressed Reproduction Of Female Ae Aegypti In a Dose-mentioning

confidence: 99%

Molecular action of pyriproxyfen: Role of the Methoprene-tolerant protein in the pyriproxyfen-induced sterilization of adult female mosquitoes

Ahmed

¹

,

Saunders

²

,

Mullins

³

et al. 2020

View full text Add to dashboard Cite

Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher's Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krü ppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF.

show abstract

“…arabiensis, An. gambiae, Culex quinquefasciatus mosquito species [15,16,37]. This conserved phenomenon in different mosquito species suggests that PPF influences multiple steps in egg maturation and that the final reproductive outcome of PPF-treated female mosquitoes reflects the cumulative effects of PPF.…”

Section: Discussionmentioning

confidence: 94%

“…The inhibitory effect of PPF on mosquito reproduction is affected by the time of exposure, formulation, methods of application, and other abiotic factors [36][37][38]. In this study, we exposed adult mosquitoes to PPF by placing them into cartons that had a lining of PPF-treated cotton gauzes.…”

Section: Ppf Suppressed Reproduction Of Female Ae Aegypti In a Dose-mentioning

confidence: 99%

The juvenile hormone receptor Methoprene-tolerant is involved in the sterilizing effect of pyriproxyfen on adultAedes aegyptimosquitoes

Ahmed

¹

,

Saunders

²

,

Mullins

³

et al. 2020

Preprint

View full text Add to dashboard Cite

Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae.aegypti females but blocked the development of primary follicles at Christopher's Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes.Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After bloodfeeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF. Author summaryAedes aegypti mosquitoes are responsible for the transmission of dengue, yellow fever, chikungunya, and Zika fever. Insecticides are widely used as the primary tool in the prevention and control of these infectious diseases. In light of the rapid increase of insecticide resistance in mosquito populations, there is an urgent need to find new classes of insecticides with a different mode of action. Here we found that pyriproxyfen, an analog of insect juvenile hormone (JH), had a large impact on the oocyte development, both before and after blood feeding, in female mosquitoes. Pyriproxyfen disturbed normal hormonal responses and caused metabolic shifting in female adults. These actions appear to collectively impair oocyte development and substantially reduce viable progenies of female mosquitoes. Besides, we demonstrated the involvement of the JH receptor Met in pyriproxyfen-induced female sterilization. ...

show abstract

Evaluating the sterilizing effect of pyriproxyfen treated mosquito nets against Anopheles gambiae at different blood-feeding intervals

Cited by 20 publications

References 18 publications

Pyriproxyfen-Treated Polypropylene Sheets and Resting Boxes for Controlling Mosquitoes in Livestock Operations

Pyriproxyfen-Treated Polypropylene Sheets and Resting Boxes for Controlling Mosquitoes in Livestock Operations

Molecular action of pyriproxyfen: Role of the Methoprene-tolerant protein in the pyriproxyfen-induced sterilization of adult female mosquitoes

The juvenile hormone receptor Methoprene-tolerant is involved in the sterilizing effect of pyriproxyfen on adultAedes aegyptimosquitoes

Contact Info

Product

Resources

About