A new type of bed net could drastically reduce malaria deaths in Kenya and other African countries prone to the disease.
Based on findings from a clinical trial conducted in Burkina Faso, scientists note that this net is more adept at fighting malaria than the regular ones, which mosquitoes are increasingly becoming resistant to.
The normal malaria control bed nets, the World Health Organisation (WHO) recommends, are treated with a class of insecticides known as pyrethroids, which kill mosquitoes that land on the nets’ surface, preventing them from biting and spreading the disease to those sleeping under the nets.
Even though they have played a key role in malaria control over the years, the nets are now under threat as malaria mosquitoes increasingly become resistant to pyrethroids hence rendering them ineffective.
To address this challenge, the new bed nets are treated with a combination of two insecticides – the usual pyrethroids and a chemical known as pyriproxyfen.
This prompts a dual attack on the mosquitoes. The pyrethroid insecticide repels and kills the mosquitoes. Then, as an insect growth regulator, the pyriproxyfen insecticide shortens the lives of mosquitoes and reduces their ability to reproduce.
Results from the new study which were published in The Lancet journal showed that in combination, the ingredients on the nets kill more mosquitoes and reduce the number of infective bites than conventional nets treated only with pyrethroids.
Indeed, the novel nets were able to cut malaria cases by 12 per cent among children that slept under them compared to those that used the conventional nets.
Children that benefited from the new bed nets were also 52 per cent less likely to suffer from anaemia caused by malaria which is a major cause of death among children below two years old. In addition, these children had a 51 per cent reduced risk of being bitten by mosquitoes (female anopheles) that spread the disease.
Consequently, the researchers suggest that the use of bed nets with a combination of chemicals should be explored for areas where mosquito resistance is a problem.
“This study is important because malaria control in sub-Saharan Africa has stalled, partly because the mosquitoes are adapting and becoming resistant to the pyrethroid insecticides used for treating the old bed nets,” said Prof Steve Lindsay, one of the study authors from the department of biosciences at Durham University in the United Kingdom.
Dr Alfred Tiono, principal investigator of the study from the Centre National de Recherche et de Formation sur le Paludisme in Burkina Faso said: “We have seen our gains in the battle against malaria progressively lost with the emergence and spread of resistant mosquitoes. The results from this trial gave us a new hope.
“This new invaluable tool would enable us to tackle more efficiently this terrible and deadly disease that affects many children. If deployed correctly, we could certainly prevent millions of cases and deaths from malaria.”
This study is the first clinical trial that has compared a bed net with two active ingredients, against the traditional widely used nets treated with the pyrethroid insecticides alone.
The research involved about 2,000 children aged between six months in Burkina Faso where mosquitoes are highly resistant to the traditional insecticide-treated nets.
Simon Kariuki, head of the malaria programme at the Kenya Medical Research Institute (Centre for Global Health Research) says the resistance problem has already been reported in Kenya. It is more prevalent in Nyanza and western Kenya where the malaria burden is also high.
The disease continues to be a major killer in the country. The 2018 Economic Survey ranked it as the second cause of death in Kenya.
Last year, more than 17,000 registered deaths were attributed to the disease, up from 16,000 in the previous years.
Health experts note that in reality, the numbers could be much higher as not all deaths caused by the ailment are usually captured or recorded. “We believe that the resistance problem is contributing to these rising cases.”
According to Dr Kariuki, having new malaria control tools such as more effective insecticides will play a key role in boosting the malaria fight.
This new study is among the few that are fronting workable solutions to tackle the insecticide resistance problem.
Early this year, the Lancet published results of a trial conducted in Tanzania which revealed that another new chemical known as piperonyl butoxide is also effective in tackling malaria-resistant mosquitoes which have ‘overpowered’ conventional bed nets treated with pyrethroids.
The WHO is still collecting and assessing these studies before it can eventually revise malaria control guidelines that will incorporate the new insecticides.
Irrespective of the resistance problem, the Ministry of Health says the nets that are currently used still play a key role in malaria prevention and should thus be embraced.
“People in high-risk malaria zones, especially pregnant women and children below five years, should all sleep under insecticide-treated bed nets to reduce their chances of getting the disease,” said Dr Kiambo Njagi, a senior officer at Ministry of Health’s malaria division.