Insecticide resistance is reaching tipping point
Vector Control Insecticide resistance threatens to undermine gains made in the fight against malaria.
Vector control, through long lasting insecticide treated nets (LLIN) and the use of indoor residual spraying (IRS), has been instrumental in cutting global malaria mortality rates by 29% since 2010, according to World Health Organisation statistics. However, resistance to synthetic pyrethyroids, which is the chemical class of active ingredients used in 100% of LLINs and roughly 60% of IRS, is now undermining these advances. 60 of the 73 countries who monitor resistance have already noticed resistance to at least one class of the insecticide and 50 have identified resistance in at least two.
“No one has been looking for a new chemistry because there is no significant market for it,” explains Dr. Nick Hamon, CEO of IVCC and an adjunct Professor of Entomology at North Carolina State University. “We are seeing resistance to pyrethroid insecticides and other classes of chemistry almost everywhere we look for it. Insecticide resistance is now reaching the tipping point.”
"Bed nets and their chemicals need to provide protection for least three years."
Research into vector control is focussed on three main areas: finding active ingredients with novel modes of action, repurposing current insecticides and targeting outdoor transmission. In recent years, alternative agents have been used in IRS and additional chemicals added to LLINs, but this is not enough. Bed nets are the main form of defense and chemicals used in them need to have very specific properties; they need to provide protection for least three years, be strong enough to kill mosquitos, safe to sleep under and able to withstand 20 washes.
60 of the 73 countries who monitor malaria insecticides have already noticed resistance in some mosquitos.
Over the past few years, with the support of product development partnerships like IVCC, major players in the agro-chemical industry have opened up their chemical libraries containing more than 4.5 million chemical compounds to allow researchers to look for high potential chemistry for public health use. Five chemical classes and nine compounds have been identified as having potential for use and are currently undergoing a major synthesis programme. Dr. Hamon is hopeful that within the next twelve months at least three will be put forward for rigorous trials in order to assess their safety and performance.
“We are hopeful that from these we will develop three new classes of chemicals that can be used in LLINs and IRS. Ideally we need to have three that can be used in rotation over the course of the next few decades in order to reach our target of eradication by 2040,” explains Dr. Hamon.
Time is very much of the essence, but many, like Dr. Hamon, believe that with current advances in vector control alongside developments in treatments, technology and education, a tool box of solutions can be created that will provide frontline staff with the resources they need to end the scourge of malaria.
IVCC is a not-for-profit public-private partnership that was established as a charity in 2005. Our mission is to save lives, protect health and increase prosperity in areas where disease transmitted by insects is endemic.
We bring together the best minds to create new solutions to prevent disease transmission. By focusing resources and targeting practical scientific solutions we accelerate the process from innovation to impact.