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Olyset Plus gave very good BFI that was superior to Olyset
Net due to the presence of PBO.
7. Olyset Plus compared with Olyset Net in experimental huts –
Cameroon.
Experimental hut trials to compare Olyset Net and Olyset
Plus were conducted in Pitoa, Cameroon. As above, the
washing methodology and protocol followed WHO
Guidelines. The local population of An. gambiae were
pyrethroid metabolic mechanism resistant.
Blood Feeding Inhibition (BFI) rates were recorded to
demonstrate the varying degrees of protection the test
nets provided. The results (Figure 10) demonstrate that
the untreated control nets gave little protection before
washing.
The unwashed Olyset Net performed well especially
considering the resistance present but Olyset Plus gave
better mosquito mortality. After 3 washes and 7 days
Olyset Net gave good levels of BFI (88%) while Olyset Plus
gave even better protection with 96% BFI. Olyset Plus also
had a better overall impact on mortality (69% vs 38% for
Olyset Net).
8. WHO Phase II Evaluation of Olyset Plus – Benin.
As part of the evaluation of Olyset Plus, Phase II experimental
hut trials were conducted in Benin by WHOPES.
These were carried out in Malanville, in an area where
increased resistance of malaria vectors to pyrethroids
(22% mortality to 0.75% permethrin) has been recently
reported. Results for wild, free flying An.gambiae are
shown in Figure 11. These show that while both nets have
given good initial levels of protection from blood feeding
before washing, Olyset Plus continues to give excellent
protection after 20 washes. Levels for Olyset Net while
still good, have declined. Mortality data follows a similar
trend, indicating that Olyset Plus is likely to have a
greater mass killing effect on these resistant populations
over time compared with Olyset Net.