Page 64 - University of Pretoria RESEARCH REVIEW 2016
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A reason for the continued prevalence of malaria in endemic areas is the lack of adequate vector control measures. Researchers in the Institute of Applied Materials (IAM) in the University’ s Faculty of Engineering, Built Environment and Information Technology are working on innovative vector mosquito-repellent inventions.
The research falls under the ambit of the UP ISMC vector control cluster.
 The World Health Organisation (WHO) recommends long-life insecticide-treated nets and indoor residual spraying for malaria vector control, but both interventions target mosquitoes that feed indoors. A significant proportion of malaria infections in Africa may be due to exposure to vector mosquitoes during the early hours of the evening when people are still active outdoors.
N,N-diethyl-meta-toluamide (DEET) is considered
to be ‘the’ mosquito repellent for outdoor personal protection because of its superior residual efficacy. However, numerous product shortcomings have indicated a need for replacements. DEET’s residual effectiveness is only a few hours. Its relatively high cost and the need for repeated application to the skin at high concentrations (10 to 70%) preclude its use
in tropical countries. There have also been emergent resistance and negative consumer perceptions with respect to aspects such as odour, high adsorption rate, oily feel on the skin and skin irritation.
IAM researchers Homa Izadi, Professor Walter
Focke and Professor Leo Braack have noted
that commercialising new active compounds
and establishing their safety for human use are time-consuming and expensive. The discovery
of synergistic mixtures of approved repellents
could provide a faster route to the public use of replacement repellents. Through their research, Izadi, Focke and Braack have discovered a special blend
of two repellents with pseudo-azeotrope behaviour that improve repellent efficacy and persistence. This approach opens the way for the development of better mosquito repellent formulations to fight mosquito-borne diseases.
Left from top: Homa Izadi, Walter Focke, Leo Braack and Mthokozisi Sibanda.
Right: Collecting vector mosquitoes in Uganda.
Another project undertaken by researchers Mthokozisi Sibanda and Professor Walter Focke,
in collaboration with Dr Andreas Leuteritz and
Dr Harald Brünig of the Leibniz Institute for Polymer Research in Dresden, Germany, has successfully produced personal protection clothing items. A need was identified for a slow-release, affordable, mosquito-repelling bi-component polymer filament
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