Dual Active Ingredient Long Lasting Insecticidal Nets (Dual AI LLIN)
Due to an increase in insecticide resistance, it is more important than ever that we focus our efforts on developing malaria control tools that will have proven public health value and that will preserve existing tools against the threat of resistance.
One Insecticide Resistance Management (IRM) strategy is to combine two or more insecticides with different modes of action in one Long Lasting Insecticidal Net (LLIN), this way the mosquito is likely to be killed by contact with the second insecticide, in the event that it survives contact with the first insecticide. To this end, IVCC is investing in the development of Dual Active Ingredient (Dual AI) mixtures for insecticidal treated nets.
In order to move away from pyrethroid only nets, and manage the threat of insecticide resistance, IVCC is working with leading agrochemical companies in developing novel insecticides for use in vector control. These insecticides also become mixture pair candidates for use in LLIN products. Potential Dual Active Ingredient Long Lasting Insecticidal Nets (Dual AI LLIN) products could be:
- Pyrethroid + Repurposed Chemistry (e.g. Interceptor® G2 and Royal Guard®)
- Pyrethroid + novel Active Ingredients (AIs)
- Novel AI + Repurposed Chemistry
- Novel AI + novel AI
Development of Nets
Although using only active ingredients with no resistance risk would be ideal for Dual AI LLINs, we currently face a challenge around the cost of these products in the market, compared to pyrethroid only products. A non-pyrethroid Dual AI LLIN, where both insecticides are at the fully effective dose, is currently more expensive to manufacture and therefore may not be competitive in today’s market. In order to overcome the pricing challenges posed by novel AIs, whilst still developing an efficacious and non-inferior LLIN, insecticidal treated net manufacturers may need to consider different net design options.
Options for net designs could be:
- Weaving design innovation where the AI is applied to every second thread.
- Partial treatment of the net (e.g. two insecticides). Research indicates >85% of mosquito activity occurs on the net roof; therefore, it may be cost effective to only apply AI to part of the net.