Technology for conversion of conventional mosquito nets in the field into long lasting bed nets

Abstract:
A new technology is described for in-field dipping of conventional mosquito nets for long lasting efficacy by adding a polymer binder to the deltamethrin treatment. Various polymer binders vary greatly in their ability to improve the retention of deltamethrin on the fiber and ensure resistance of the treatment over time and after washing. For each individual binder, the optimum ratio between binder and deltamethrin needs to be identified, ensuring resistance of the treatment against numerous washings and at the same time allowing the full bioavailability of the insecticide for fast knock down (KD) efficacy and high mosquito mortality. The results of bioassay of a type of treated net vary depending on what type of soap is used, and at what concentration. The higher concentrated solutions of Savon de Marseille (SdM) had a higher pH and were much more aggressive than the ones at lower concentration. However, various African soaps had an effect equivalent to SdM although their pH was higher. The new technology for in–field dipping of conventional mosquito nets will be marketed under the name of K-O TAB® 1-2-3 is based on an existing deltamethrin water dispersible tablet, K-O TAB®, at the dose rate of 25 mg deltamethrin / m2 as recommended by WHO. Treated nets show mortality of Anopheles stephensi mosquitoes of 97% even after 20 washes, and 100% mosquito knock down is achieved throughout from the first to the twentieth washing.