Vector control
A powerful new defence against malaria mosquitos
Imergard™ WP (wettable powder) is a perlite-based indoor and outdoor residual spray designed to provide a physical mode of action against mosquitoes capable of harbouring or transmitting human disease.
In their 2019 annual report, the World Health Organization reported 405,000 deaths from malaria, 67% of which were children under the age of 5 years old. Indoor residual sprays (IRS) have been an effective strategy to control malaria transmission and have helped reduce deaths in recent years. However, the overuse of traditional IRS pesticides has pushed natural selection towards resistance. Fewer people at risk of malaria are being protected by the IRS, declining from a peak of 5% coverage in 2010 to 2% in 2018, primarily as a result of insecticide resistance and rising costs of new technologies.
A new mode of action IRS with 11 months’ residual efficacy
Imergard WP can be applied to interior walls using standard backpack spray equipment. When the mosquito lands on a treated surface, there is a static transfer of Imergard WP particles, which absorb the lipid layer necessary for the mosquito’s survival.
In a community trial of 4,000 homes, completed in 2020 in Tanzania, Imergard WP was able to control the malaria parasite as effectively as the gold standard positive control, a micro-encapsulated Pirimiphos-methyl IRS.
At the conclusion of the study, Imergard WP maintained 100% efficacy after 72 hours against a threshold target of 80% mortality on all substrates for 11 months. An IRS that has 11 months of residual efficacy means it can be applied at any time of the year and not just during mosquito season, potentially driving an increase in IRS coverage.
High user acceptance and new potential treatment areas
There was a high level of user acceptance in the community trial involving 15 villages and 13,540 men, women and children. No serious adverse events were reported among sprayers or residents.
Imergard WP, like other IRS technologies, does not stop mosquitoes from blood-feeding; this is where insecticide-treated bednets (ITNs) have proven an invaluable tool with 50% of the population at risk being protected in 2018. However, in 2018 nearly 40% of pregnant women and children under five years of age, the most vulnerable population, did not sleep under an ITN.
The primary objective of employing IRS as a strategy for malaria control is to limit the spread of the malaria parasite. After a blood meal, mosquitoes typically rest indoors prior to laying eggs. If mosquitoes don’t live longer than 10-14 days they will not live long enough to transmit the malaria parasite.
Imergard WP’s advantage is that it provides a physical mode of action and is a powerful tool in resistance management. It is not a silver bullet, but it will deter cross-chemical resistance development and complement traditional and new IRS chemistry.
Since Imergard WP is not subject to UV or heat degradation, it potentially opens up a new large surface area for residual application, e.g. outdoor surfaces that are undercover and indoor metal roofs.
No physical, chemical, human health or environmental hazards
The active ingredient of Imergard WP is perlite, which has been processed to release its undiscovered insecticidal properties. Since the accidental discovery of expanded perlite in 1939, it has been used in a wide range of industrial applications, including cosmetics, agriculture & horticulture, air and liquid filtration, fireproofing and insulation.
Imergard WP has demonstrated efficacy against multiple Anopheles, Aedes and Culex s.s. It has a Toxicity Class IV rating, which is the lowest rating, and is non-toxic to bees when applied topically as a liquid suspension or a powder.
Imergard WP features and benefits
- 11 months residual efficacy
- Produced from a renewable and sustainable resource
- A physical mode of action offers a new resistance management tool to deter cross-chemical resistance development
- Use of Imergard WP in rotation, mosaic or formulated with other IRS may be beneficial for insecticide resistance management
- Five-year shelf life so it can be distributed to application sites months or years in advance
- Applied with standard IRS backpack sprayers. Visual application cues allow sprayers and home residents to see where it has been sprayed
- No odor and residents can enter the house immediately after application
- Does not heat degrade so can be applied to tin ceilings
- Demonstrated efficacy against multiple Anopheles, Aedes and Culex s.s.
- Lowest Toxicity Class IV rating and is non-toxic to bees
