The use of mosquito nets treated with long lasting insecticide remains the most cost-effective and reliable way to control malaria in Kenya and is backed by the World Health Organisation (WHO) as key to rolling back the spread and incidence of malaria globally.
Malaria is a disease caused by parasites transmitted to humans through the bites of infected female Anopheles mosquitoes. However, it can be prevented using long lasting insecticidal nets (LLIN), and victims can be cured if they are diagnosed early and receive treatment.
According to the WHO, 92 percent of malaria cases and 9 percent of malaria deaths in 2017 were in Africa. This is huge.
It is a major public health concern for Kenya, with 70 percent of the population at risk of contracting the disease, out of which 14 million live in endemic areas, and 17 million in areas of epidemic and seasonal malaria.
Although the efficacy of LLINs are not in doubt, research is now proving that unless their quality is consistently monitored, they could undermine global efforts to roll back malaria infection in Kenya and Africa.
The insecticide used in LLINs can be incorporated into the net’s fibre during its manufacture or coated on the finished net using a binding agent. The advantage of LLINs is that they remain effective for up to 20 washes and can last three to four years whereas normal insecticide treated nets (ITNs) need to be re-treated after one or two washes and can only last up to a year before having to be discarded.
One study in rural Kenya examined mean time to ITN failure and found that 82 percent of one brand of LLIN were still effective after 23 washes.
The WHO currently recommends three LLINs under its Pesticide Evaluation Scheme. They are Olyset Net®, PermaNet® and Interceptor®. Unfortunately, it is not easy to physically distinguish normal insecticide treated nets (ITNs) from LLINs as they look very similar.
ITNs are widely distributed by the government and its partners in the fight against malaria, but many cannot afford to buy the insecticide tablets needed to treat them. According to the Malaria Consortium, malaria interventions should therefore include regular treatment of untreated nets.
A big challenge to using LLINs is the emergence of parasite resistance to antimalarial medicines and of mosquito resistance to insecticides. This requires regular monitoring and assessment of both the vector (mosquitoes) and the efficacy of LLINs in use so that interventions can be modified to avoid development of resistance to insecticides.
Studies show that differences in use and wear of LLINs lead to them losing residual insecticide faster and so being less effective in preventing malaria.
Another danger is overuse of insecticides on nets and through indoor residual spraying and agricultural increasing the risk of mosquito resistance. In fact, the WHO has noted that gains since 2000 in vector control interventions in sub-Saharan Africa are at risk emerging resistance to pyrethrum-based insecticides among Anopheles mosquitoes.
Despite this the WHO still strongly recommends insecticide-treated ITNs and LLINs for use as protection in most settings based on a 5-country study it coordinated between 2011 and 2016.
According to a Cochrane review, when full coverage is achieved, ITNs reduce early childhood mortality by 17 percent on average compared with no nets in sub-Saharan Africa. This implies that, in general, 5.5 lives could be saved every year for every 1000 children under five years of.
Although LLINs are the cheapest and most effective interventions against malaria – the annual average is US$ US$ 1.05 per person per year – with most of the population living below $1 per day, there has been a rise in sub-standard LLINs. These have put at risk malaria prevention programmes.
Their existence is fueled in part by the lack of information to the community about the importance of using approved and standardized LLINs and the benefits of investing in such a preventive measure.
Communities need proper and regular education on how to care for their LLINs including how frequently they can wash them, and to mend any holes and not dry them in direct sunlight. They also need to understand that reducing mosquito populations through such measures as eliminating their breeding grounds is the first point of defence in malaria prevention and control.
The WHO Global Technical Strategy for Malaria 2016-2030 was adopted by the World Health Assembly in May 2015 to guide and support regional and country malaria control and elimination programmes. It targets to the following by 2030:
• Lower malaria case incidence by at least 90 per cent.
• Reduce malaria mortality rates by at least 90 per cent.
• Eliminate malaria in at least 35 countries.
• Prevent a resurgence of malaria in all countries that are malaria-free.
But to win the fight against malaria, the multi sectorial comprehensive approach adopted by the Kenya government is still the best. Public private partnerships to implement vector control measures and early diagnosis and treatment and use of quality LLNIPs and ITNs by at risk populations will continue to lower early childhood mortality caused by malaria infections.