Malaria is an infectious disease that has infected 228 million people, and died about 405,000 cases in 2018 alone, 94% of them in Africa alone, according to the 2019 World Malaria Report.
Malaria is an infection caused by a unicellular parasite, which penetrates into the bloodstream through the mosquito bite.
The use of mosquito nets treated with insecticides is the most common and effective way to reduce mosquitoes, but the mosquito's resistance to pesticides is common in use such as pyrethroids increase year after year, so there is an urgent need for a safe alternative chemical to be used in controlling mosquitoes.
Recently, researchers have succeeded in devising an effective alternative against the Peruvian bacterium Anopheles mosquito in South Africa.
Their study, published in the journal "Insect" on May 23, showed that a spray prepared by mixing volcanic glass powder with water showed effective control of mosquitoes carrying malaria.
Volcanic glass
Volcanic glass is a type of amorphous rock that results in a rapid cooling process of magma. It is a mixture of molten silica materials with volatile solids from volcanoes.
The volcanic glass material used in this new insecticide is perlite, an industrial mineral that is frequently used in building materials and in gardens as an additional soil material.
This new insecticide, called "Emergard WP", can be used on walls and interior ceilings as a spray that does not contain additional chemicals.
The results of the study showed that this method is useful in reducing mosquitoes that are pregnant with many diseases in Africa, and that the new pesticide is not toxic to mammals, and it will be very cost-effective.
Study details
In the study, entomologists at North Carolina State University worked with a large team of researchers at the Innovative Vector Control Federation, based at the Liverpool School of Tropical Medicine, and Emerys Mineral Purification Company to test the new pesticide.
The researchers used the spray in experimental huts in the Republic of Benin (West Africa) to test its effects on both wild strains and "Gambian Anopheles" mosquitoes, whose importance is highlighted as being the main vector of malaria in sub-Saharan Africa.
The researchers used four different tests to verify the effectiveness of the new pesticide. The first group was control study huts, and they had no mosquito spray.
In the second group, the walls of the hut were covered with pyrethroids, and in the third group, the walls of the hut were sprayed with a new pesticide spray, while the walls of the hut were sprayed with a mixture of pyrethroids and the new pesticide in group IV.
The huts with walls treated with the new pesticide spray, with or without pyrethroids, showed the largest mosquito mortality rates.
The results showed that adult mosquito mortality rates on the walls treated with the new pesticide spray were greater than 80% until five months after treatment, and 78% after six months.
Mosquito mortality rates in huts that were sprayed with common insecticides only were about 40 - 45% over five months, with these rates dropping to 25% in the sixth month of the study.
The first mechanical pesticide
The new pesticide is the first quick-acting mechanical insecticide, providing a physical way of working, and sticking to walls to provide long-term protection from mosquitoes that cannot develop any immunity against it.
"Perlite molecules essentially remove water from mosquitoes," Mike Rowe, a professor of entomology at North Carolina State University and co-author of the study, told the university's news page.
"Many die within a few hours of contact with the treated surface. Mosquitoes do not repel the treated surface because they have no smell mechanism for the smell of rock," he added.
More studies are needed to fully understand the potential of this new technology, said David Stewart, Emerys Commercial Development Director and co-author of the study, "Preparing perlite as an insecticide is a new thing."
"This material is not a silver bullet but a new tool that can be considered as part of the vector management program," he added.