TY - JOUR
T1 - A deltamethrin crystal polymorph for more effective malaria control
AU - Yang, Jingxiang
AU - Erriah, Bryan
AU - Hu, Chunhua T.
AU - Reiter, Ethan
AU - Zhu, Xiaolong
AU - López-Mejías, Vilmalí
AU - Carmona-Sepúlveda, Isis Paola
AU - Ward, Michael D.
AU - Kahr, Bart
N1 - Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/10/27
Y1 - 2020/10/27
N2 - Pyrethroid contact insecticides are mainstays of malaria control, but their efficacies are declining due to widespread insecticide resistance in Anopheles mosquito populations, a major public health challenge. Several strategies have been proposed to overcome this challenge, including insecticides with new modes of action. New insecticides, however, can be expensive to implement in low-income countries. Here, we report a simple and inexpensive method to improve the efficacy of deltamethrin, the most active and most commonly used pyrethroid, by more than 10 times against Anopheles mosquitoes. Upon heating for only a few minutes, the commercially available deltamethrin crystals, form I, melt and crystallize upon cooling into a polymorph, form II, which is much faster acting against fruit flies and mosquitoes. Epidemiological modeling suggests that the use of form II in indoor residual spraying in place of form I would significantly suppress malaria transmission, even in the presence of high levels of resistance. The simple preparation of form II, coupled with its kinetic stability and markedly higher efficacy, argues that form II can provide a powerful, timely, and affordable malaria control solution for low-income countries that are losing protection in the face of worldwide pyrethroid resistance.
AB - Pyrethroid contact insecticides are mainstays of malaria control, but their efficacies are declining due to widespread insecticide resistance in Anopheles mosquito populations, a major public health challenge. Several strategies have been proposed to overcome this challenge, including insecticides with new modes of action. New insecticides, however, can be expensive to implement in low-income countries. Here, we report a simple and inexpensive method to improve the efficacy of deltamethrin, the most active and most commonly used pyrethroid, by more than 10 times against Anopheles mosquitoes. Upon heating for only a few minutes, the commercially available deltamethrin crystals, form I, melt and crystallize upon cooling into a polymorph, form II, which is much faster acting against fruit flies and mosquitoes. Epidemiological modeling suggests that the use of form II in indoor residual spraying in place of form I would significantly suppress malaria transmission, even in the presence of high levels of resistance. The simple preparation of form II, coupled with its kinetic stability and markedly higher efficacy, argues that form II can provide a powerful, timely, and affordable malaria control solution for low-income countries that are losing protection in the face of worldwide pyrethroid resistance.
KW - Deltamethrin
KW - Epidemiological modeling
KW - Malaria
KW - Mosquito
KW - Polymorphism
UR - http://www.scopus.com/inward/record.url?scp=85094866754&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85094866754&partnerID=8YFLogxK
U2 - 10.1073/pnas.2013390117
DO - 10.1073/pnas.2013390117
M3 - Article
C2 - 33046642
AN - SCOPUS:85094866754
SN - 0027-8424
VL - 117
SP - 26633
EP - 26638
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 43
ER -