Two weeks ago, The Lancet published a promising study on the effectiveness of a new type of mosquito net. After a two-year trial period in Burkina Faso, the researchers found the new mosquito nets, treated with two insecticides, decreased cases of malaria by 12 percent. These findings promise strong potential for lowering the risk of malaria worldwide with the implementation of these new mosquito nets.
This research is a collaboration among several institutions including Durham University, Burkina Faso’s National Center for Malaria Research and Training, Liverpool’s School of Tropical Medicine and the Swiss Tropical and Public Health Institute.
According to The World Health Organization, almost 50 percent of the world’s population was at risk of contracting malaria in 2016. While risk areas exist around the world, sub-Saharan Africa suffers the most cases of malaria each year.
In 2016, sub-Saharan Africa had 90 percent of the world’s malaria cases and 91 percent of the world’s malaria-related deaths. Though malaria-related deaths have declined significantly, from 440,000 in 2010 to 285,000 in 2016, malaria is still a great threat to health worldwide. Traditional, chemically-treated mosquito nets have helped to reduce the cases of malaria, however, as mosquitoes grow more resistant, these traditional nets have become less effective, leaving users more vulnerable to malaria infection.
The World Health Organization estimated there were five million more cases of malaria in 2016 compared to the total number of malaria cases in 2015. The above-mentioned study’s mosquito nets address this problem, by targeting insecticide-resistant mosquitoes that are causing these problems.
New Mosquito Nets
The older mosquito nets generally have a pyrethroid insecticide treatment, intended to kill mosquitoes on contact. This treatment has become less effective with time since the mosquitoes have developed a resistance to the insecticide. The new nets, presented in the research, combat this issue, by using a different insecticide.
The new insecticide is effective because it combines traditional pyrethroid treatment with another agent, pyriproxyfen. Pyriproxyfen works as an insect growth regulator, shortening the lifespan of mosquitoes and thus their ability to transmit disease, as well as reproduce.
According to professor Steve Lindsay, who worked on the study, this combination of chemicals has three main benefits: it kills more mosquitos, reduces the number of mosquito bites and decreases the likelihood that mosquitoes will develop resistance to the chemical mixture.
Results in Burkina Faso
A two-year trial, conducted in Burkina Faso, demonstrated the effectiveness of these new mosquito nets, treated with pyrethroid and pyriproxyfen. Burkina Faso was ideal for the study, due to the high number of malaria cases. Located in sub-Saharan Africa, Burkina Faso has more than 10 million cases of malaria every year. Mosquitoes in Burkina Faso were also ideal test subjects since they exhibit high resistance to pyrethroid treatment. According to Professor Lindsay, 80 percent of mosquitoes in Burkina Faso are so resistant to pyrethroid, they are no longer killed by it.
Researchers conducted the study in 91 villages throughout rural areas of the country. By switching traditional mosquito nets with nets treated with the new chemical blend, researchers saw a 12 percent decrease in malaria cases. Furthermore, the overall exposure to mosquitoes dropped by over 50 percent during the test period.
With these results, the researchers concluded the trial mosquito nets offer increased protection against malaria as opposed to standard pyrethroid-treated nets. They also recommended that these new nets replace standard nets in areas with high malaria transmission rates and high instances of insecticide resistance among mosquitoes.
Although 12 percent reduction in malaria cases may seem marginal, on a global scale and in real numbers, this decrease in malaria infection would be monumental. As Professor Lindsay noted, if the nets were used across all of Burkina Faso during the two-year trial, researchers would expect 1.2 million fewer cases of malaria in the population overall.
Dr. Alfred B. Tiono, who headed the field study, has great hope for the impact these new mosquito nets could have globally. He believes, if used correctly, the nets could prevent millions of malaria cases worldwide. It is still unclear how costly large-scale manufacturing of the dual-chemical nets will be. However, Professor Lindsay remains hopeful the manufacturing costs will not exceed the costs of producing traditional nets. If only one life is saved by applying the new nets, no price is too high to pay.
– Morgan Harden