Monday, August 24, 2015

Home Dipping Mosquito nets can be done safely at home

By Esther Nakkazi

To remain effective, insecticide-treated nets must remain toxic to mosquitoes even after being washed many times.

Researchers have now found that a new treatment for the nets, called ICON Maxx, a long-lasting treatment kit for mosquito nets, makes the toxins more resistant to washing – so the nets still kill more than half of insects after 20 washes.

ICON Maxx uses a ‘dip-it-yourself’ kit for long-lasting treatment of polyester nets. It comes in a twin- sachet kit that contains a slow-release capsule suspension of lambda-cyhalothrin plus a binding agent.

But the idea of home-dipping the net remains scary as the solution containing ICON Maxx is poisonous and poses a health risk. However, researchers say it can be done safely by communities even without basic education and its cheap.

“Dipping a net with a treatment that can make it insecticidal or to remain effective against insect vectors like mosquitoes, for the life time of the net regardless of washes can easily be absolved by communities especially those living in malaria endemic countries,” said Patrick Tungu.

“It does not require technical expertise to impregnate a net. It is a simple procedure, just dipping a net into a solution containing Icon Maxx, that can be adopted by any person regardless of their education level,” said Tungu.

Tungu said communities can easily adopt this technique because its cheap. Currently, the price of the kit to treat one bed net costs USD $3.

To determine whether ICON Maxx meets the standards required by the World Health Organization Pesticide Evaluation Scheme (WHOPES), researchers from Tanzania and the London School of Hygiene and Tropical Medicine, London, UK evaluated nets efficacy and wash fastness against wild, free-flying anopheline mosquitoes in Tanzania.

According to a paper published in February 2015 in the malaria journal, a part of the BioMed Central journals, ICON Maxx demonstrated superior wash resistance to the conventional lambda-cyhalothrin treated nets (CTN).

This finding raises the prospect of conventional polyester nets and other materials being made long- lastingly insecticidal through simple dipping in community or home, and thus represents a major advance over conventional pyrethroid treatments, says the paper.

The researchers evaluated two types of nets, untreated nets and treated either with the conventional lambda-cyhalothrin or ICON Maxx.

Five treatment arms were tested; unwashed ICON Maxx net, ICON Maxx net washed 20 times, polyester net conventionally treated with lambda- cyhalothrin at 15 mg/m2 and washed four times, polyester net conventionally treated with lambda-cyhalothrin at 15 mg/m2 and washed 20 times and untreated unwashed polyester net.

They looked at mosquito mortality, blood feeding inhibition and personal protection of nets.
ICON Maxx killed 75 % of Anopheline funestus, 71 % of Anopheline gambiae and 47 % of Anopheline arabiensis when unwashed and 58, 66 and 42 %, respectively, when 20 times washed.

CTN killed 52 % of Anopheline funestus, 33 % of Anopheline gambiae and 30 % of Anopheline arabiensis when washed to the cut-off threshold of four washes and 40, 40 and 36 %, respectively, when washed 20 times.

Nets treated with ICON Maxx and washed 20 times met the approval criteria set by WHOPES for Phase II trials in terms of mortality and blood-feeding inhibition.

“The biggest threat to malaria vector control now is insecticide resistance. Pyrethroid resistance is catching up with us and we need new tools,” said Dr. Ambrose Talisuna, a Senior Clinical Research Fellow, Public Health and Health Systems Research University of Oxford-KEMRI-Wellcome Trust Programme.


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