Download PDF - Olyset Net

%
Figure 9. Blood Feeding Inhibition in hut trials against resistant
mosquitoes in Benin.
100
90
80
70
60
100
80
60
%
40
%
100 100
Kisumu before
washing
100
95.1
Kisumu after
washing
(3x+7 days)
84.6
82
70.2
KDR +
Metabolic
before
washing
Ref: C.Pennetier, V.Corbel et al. DOC/IRD/CREC/02/10
20
0
87.1
KDR +
Metabolic
after washing
(3x+7 days)
97.4 100 88
Metabolic
before
washing
BFI
Olyset Net
Olyset Plus
96.1
Metabolic
after washing
(3x+7 days)
Figure 10. Experimental hut trials in Cameroon: Olyset Net and
Olyset Plus
.6
Control
97.4
75.8
Olyset Net
Unwashed
100 97.5
Olyset Plus
Ref: C.Pennetier, V.Corbel et al. DOC/IRD/CREC/02/10
100
80
60
40
20
0
.5
Control
88.0
38.0
Olyset Net
3 washes + 7 days
Figure 11. WHOPEs Phase II experimental hut trials,
Malanville, Benin.
83.2
80.6
Olyset Plus
unwashed
79.4
67.3
Olyset Plus 20
times washed
Ref: CREC/IRD WHOPES Phase II report 31/1/2012
81.6
Blood Feeding Inhibition
Mortality corrected
for control
41.7
Olyset Net
unwashed
59.9
36.3
Olyset Net 20
times washed
Mortality
96.1
68.6
Olyset Plus
These studies also demonstrated that Olyset Plus
regenerated very rapidly and was active again 1 day after
washing.
6. Olyset Plus compared with Olyset Net in experimental huts – Benin.
Trials were conducted in Cotonou, Benin using experimental
huts to compare activity of Olyset Net and Olyset Plus.
The washing methodology and experimental protocol
followed the WHO Guidelines for testing long lasting nets
(WHO/CDS/WHOPES/GCDPP/2005.11). Both LLINs had six
holes cut in them to simulate torn nets and a volunteer
slept under the nets. Mosquitoes therefore had access to a
blood meal or were inhibited from feeding and exited the
hut to a veranda trap. Three An. gambiae strains were used
– susceptible (Kisumu), Kdr + metabolic resistant and
metabolic only resistant. The mosquitoes were released
into the hut in known numbers on different nights and
Blood Feeding Inhibition (BFI) recorded to demonstrate
the varying degrees of protection the test nets provided.
The results are shown in Figure 9 where it can be seen
that with susceptible mosquitoes there was little difference
before washing, while after washing the Olyset Plus
The unwashed Olyset Net performed well especially
considering the resistance present but Olyset Plus gave
better mosquito mortality.
was slightly more effective due to faster regeneration and
also to the additional performance enhancement that
comes from the synergistic effects of PBO. When both nets
were tested against Kdr + metabolic resistant mosquitoes
the performance was not dissimilar before washing but
after washing there was a dramatic difference as the BFI
was far higher with Olyset Plus showing a protective
effect. The BFI in this Olyset Plus treatment was 87.1%
which is good considering that with Kdr resistance
(caused by insensitivity of the insect nervous system to
insecticide) PBO would be expected to add little benefit.
When tested against metabolic only resistant mosquitoes
8