In the largest ever study to assess the power of long-lasting insecticide nets (LLIN) that was carried out in Uganda, researchers found a 27% reduction in the number of children that got malaria due to the use of piperonyl butoxide (PBO), a new chemical formulation, compared to those who slept in nets that were simply treated with pyrethroid insecticides.
Researchers have discovered a new chemical formulation that counters the mechanism by which mosquito are able to resist the power of pyrethroid insecticides – whose power to kill the bugs had become seriously eroded over the years.
In the largest ever study to assess the power of long-lasting insecticide nets (LLIN) that was carried out in Uganda, researchers found a 27% reduction in the number of children that got malaria due to the use of piperonyl butoxide (PBO), a new chemical formulation, compared to those who slept in nets that were simply treated with pyrethroid insecticides.
Releasing results of their study this week during the Annual Meeting of American Society of Tropical Medicine and Hygiene (ASTMH) held at the National Harbour, Maryland, USA, researchers indicate that piperonyl butoxide (PBO)—a chemical that blocks enzymes mosquitoes employ to “detoxify” pyrethroids remained effective in killing mosquitoes, 12 months after the nets were distributed.
“We think nets with this new formulation would do a better job of preventing malaria than standard nets, particularly in areas of high-level insecticide resistance, and could reduce the burden of malaria,” said Dr. Sarah Staedke, a Uganda-based malaria epidemiologist with the London School of Hygiene and Tropical Medicine and the Infectious Disease Research Collaboration, a co-leader of the project.
The study findings also lifts the veil over the low levels of effectiveness among pyrethroid-based insecticide sprays that are on sale in Uganda with vendors claiming that they kill the bugs.
Indeed, the study shows that the mosquitoes us of its defence mechanism had rendered the Long Lasting Nets less effective and contributed to a recent stall in the decline of malaria infections and deaths —and to a rise of both in some parts of Africa.
Martin Donnelly, MSc, PhD, an expert in the genetics of insecticide resistance at the Liverpool School of Tropical Medicine and co-leader of the LLIN Evaluation in Uganda Project however warns that that while the increased efficacy offered by PBO-treated nets is great news, their efficacy could still be eroded over time as mosquitoes evolve to evade the compound.
But he thinks that the PBO nets could be a very good stopgap for several years. In the Meantime, the World Health Organization (WHO) is set to review the evidence from the Uganda Study to determine whether to recommend their adoption while testing continues for a long-term Solution.
It has also been reported that WHO trying to use a novel insecticide that employs a different mode of action than pyrethroids to kill mosquitoes.
The study also shows that despite rising levels of resistance, the non-PBO nets still contributed to reducing the prevalence of malaria parasite.
