Negative cross resistance mediated by co-treated bed nets: a potential means of restoring pyrethroid-susceptibility to malaria vectors.
Insecticide-treated nets and indoor residual spray programs for malaria control are entirely dependent on pyrethroid insecticides. The ubiquitous exposure of Anopheles mosquitoes to this chemistry has selected for resistance in a number of populations. This threatens the sustainability of our most effective interventions but no operationally practicable way of resolving the problem currently exists. One innovative solution involves the co-application of a powerful chemosterilant (pyriproxyfen or PPF) to bed nets that are usually treated only with pyrethroids. Resistant mosquitoes that are unaffected by the pyrethroid component of a PPF/pyrethroid co-treatment remain vulnerable to PPF. There is a differential impact of PPF on pyrethroid-resistant and susceptible mosquitoes that is modulated by the mosquito's behavioural response at co-treated surfaces. This imposes a specific fitness cost on pyrethroid-resistant phenotypes and can reverse selection. The concept is demonstrated using a mathematical model.
MRC Centre for Outbreak Analysis and Modelling, Imperial College, London, United Kingdom.
Michael T
MT
White
Ifakara Health Institute, Ifakara, Tanzania.
Dickson
D
Lwetoijera
MRC Centre for Outbreak Analysis and Modelling, Imperial College, London, United Kingdom.
John
J
Marshall
University of Nottingham, Sutton Bonington, Leicestershire, United Kingdom.
Geoffrey
G
Caron-Lormier
INRA, UMR 1347 Agroécologie, Pôle ECOLDUR, Dijon, France.
David A
DA
Bohan
University of Hertfordshire, Hatfield, Hertfordshire, United Kingdom.
Ian
I
Denholm
QIMR Berghofer Medical Research Institute, Brisbane, Australia.
Gregor J
GJ
Devine
D000465:Algorithms; D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000235:genetics; D005260:Female; D056084:Genetic Fitness; D007305:Insecticide Resistance; D057148:Insecticide-Treated Bednets; D007306:Insecticides / Q000494:pharmacology*; D008288:Malaria / Q000635:transmission; D008962:Models, Theoretical; D011722:Pyrethrins / Q000494:pharmacology*
D007306:Insecticides; D011722:Pyrethrins