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Lessons learned, challenges and outlooks for decision-making after a decade of experience monitoring the impact of indoor residual spraying in Benin, West Africa
Albert Salako
Corresponding Author
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This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Malaria Journal.
Background: Since 2008, Indoor Residual Spraying (IRS) has been performed in Benin in 19 districts, including 4 in southern Benin, 9 in Atacora, and 8 in Atacora, Alibori and Donga in northern Benin. However, Benin still struggles with questions about IRS cost benefit and epidemiological impact. Lessons learned and challenges from 10 years of IRS in Benin to be shared with the stakeholders involved in vector control implementation for decision-making.
Methods: Entomological parameters have been assessed entomological parameters in IRS communes since 2008. In all IRS intervention communes, decreases in human biting rate (HBR) of Anopheles gambiae, blood feeding inhibition and entomological inoculation rate (EIR) as compared to control district have been measured.
Results: EIR was reduced by 80-90%, which is encouraging, but should be observed with caution because: (i) the reduction may be insufficient to decrease epidemiological indicators given that the residual EIR in IRS districts is still higher than it is in some regions of stable malaria; (ii) the reduction in EIR is based on comparisons with control communes, but it is difficult to select control areas with the same environmental characteristics as intervention areas; (iii) despite the reduction, half of all mosquitoes that entered IRS-treated houses succeeded in taking human blood meals. Further, there are behaviours among Benin’s population that limit IRS efficacy, including recent data showing that >90% of people are not protected by IRS between 7-10 PM. This is due to the fact that they remain outdoors and that most people are not protected from mosquito bites after 10 PM because they either sleep outdoors without IRS protection or indoors without an ITN. Moreover, people have large amounts of clothing hanging on walls where mosquitoes can rest instead of IRS-treated walls. Finally, other components are important to consider in implementing IRS among which: (i) Vector resistance management strategies are sometimes poorly understood; this is actually different from the need to replace one insecticide with another after the emergence of resistance; (ii) African countries should prepare to finance IRS themselves.
Conclusion: To curtail residual malaria transmission, additional interventions able to target vectors escaping IRS should be prioritized.
Keywords
IRS, Lessons learned, challenges, outlooks, Benin
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CURRENT STATUS: Published
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Posted 20 Jan, 2020
Published
On 28 Jan, 2020
No community comments so far
Editor assigned
On 17 Jan, 2020
Editorial decision: Accept
On 17 Jan, 2020
Submission checks complete
On 16 Jan, 2020
Editor invited
On 16 Jan, 2020
No comments provided
Editorial decision: Minor Revision
On 15 Jan, 2020
Editor assigned
On 14 Jan, 2020
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On 13 Jan, 2020
Editor invited
On 13 Jan, 2020
No comments provided
Review #2 received
Received 12 Jan, 2020
Editorial decision: Minor Revision
On 12 Jan, 2020
Reviewer #2 agreed
On 11 Jan, 2020
Editor assigned
On 07 Jan, 2020
Reviewers invited
Invitations sent on 07 Jan, 2020
Reviewer #1 agreed
On 07 Jan, 2020
Review #1 received
Received 07 Jan, 2020
Submission checks complete
On 06 Jan, 2020
Editor invited
On 06 Jan, 2020
No comments provided
Editorial decision: Major Revision
On 14 Dec, 2019
Review #2 received
Received 13 Dec, 2019
Reviewer #6 agreed
On 11 Dec, 2019
Reviewer #5 agreed
On 06 Dec, 2019
Reviewer #4 agreed
On 05 Dec, 2019
Reviewer #2 agreed
On 02 Dec, 2019
Reviewer #3 agreed
On 02 Dec, 2019
Reviewers invited
Invitations sent on 29 Nov, 2019
Reviewer #1 agreed
On 29 Nov, 2019
Review #1 received
Received 29 Nov, 2019
Editor assigned
On 24 Nov, 2019
Submission checks complete
On 23 Nov, 2019
Editor invited
On 23 Nov, 2019
First submitted
On 22 Nov, 2019
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Subject Areas
Infectious Diseases
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This preprint is under consideration at Malaria Journal. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Lessons learned, challenges and outlooks for decision-making after a decade of experience monitoring the impact of indoor residual spraying in Benin, West Africa
Albert Salako
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
Version 4
Posted 20 Jan, 2020
Published
On 28 Jan, 2020
No community comments so far
Editor assigned
On 17 Jan, 2020
Editorial decision: Accept
On 17 Jan, 2020
Submission checks complete
On 16 Jan, 2020
Editor invited
On 16 Jan, 2020
No comments provided
Editorial decision: Minor Revision
On 15 Jan, 2020
Editor assigned
On 14 Jan, 2020
Submission checks complete
On 13 Jan, 2020
Editor invited
On 13 Jan, 2020
No comments provided
Review #2 received
Received 12 Jan, 2020
Editorial decision: Minor Revision
On 12 Jan, 2020
Reviewer #2 agreed
On 11 Jan, 2020
Editor assigned
On 07 Jan, 2020
Reviewers invited
Invitations sent on 07 Jan, 2020
Reviewer #1 agreed
On 07 Jan, 2020
Review #1 received
Received 07 Jan, 2020
Submission checks complete
On 06 Jan, 2020
Editor invited
On 06 Jan, 2020
No comments provided
Editorial decision: Major Revision
On 14 Dec, 2019
Review #2 received
Received 13 Dec, 2019
Reviewer #6 agreed
On 11 Dec, 2019
Reviewer #5 agreed
On 06 Dec, 2019
Reviewer #4 agreed
On 05 Dec, 2019
Reviewer #2 agreed
On 02 Dec, 2019
Reviewer #3 agreed
On 02 Dec, 2019
Reviewers invited
Invitations sent on 29 Nov, 2019
Reviewer #1 agreed
On 29 Nov, 2019
Review #1 received
Received 29 Nov, 2019
Editor assigned
On 24 Nov, 2019
Submission checks complete
On 23 Nov, 2019
Editor invited
On 23 Nov, 2019
First submitted
On 22 Nov, 2019
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Infectious Diseases
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Malaria Journal.
Background: Since 2008, Indoor Residual Spraying (IRS) has been performed in Benin in 19 districts, including 4 in southern Benin, 9 in Atacora, and 8 in Atacora, Alibori and Donga in northern Benin. However, Benin still struggles with questions about IRS cost benefit and epidemiological impact. Lessons learned and challenges from 10 years of IRS in Benin to be shared with the stakeholders involved in vector control implementation for decision-making.
Methods: Entomological parameters have been assessed entomological parameters in IRS communes since 2008. In all IRS intervention communes, decreases in human biting rate (HBR) of Anopheles gambiae, blood feeding inhibition and entomological inoculation rate (EIR) as compared to control district have been measured.
Results: EIR was reduced by 80-90%, which is encouraging, but should be observed with caution because: (i) the reduction may be insufficient to decrease epidemiological indicators given that the residual EIR in IRS districts is still higher than it is in some regions of stable malaria; (ii) the reduction in EIR is based on comparisons with control communes, but it is difficult to select control areas with the same environmental characteristics as intervention areas; (iii) despite the reduction, half of all mosquitoes that entered IRS-treated houses succeeded in taking human blood meals. Further, there are behaviours among Benin’s population that limit IRS efficacy, including recent data showing that >90% of people are not protected by IRS between 7-10 PM. This is due to the fact that they remain outdoors and that most people are not protected from mosquito bites after 10 PM because they either sleep outdoors without IRS protection or indoors without an ITN. Moreover, people have large amounts of clothing hanging on walls where mosquitoes can rest instead of IRS-treated walls. Finally, other components are important to consider in implementing IRS among which: (i) Vector resistance management strategies are sometimes poorly understood; this is actually different from the need to replace one insecticide with another after the emergence of resistance; (ii) African countries should prepare to finance IRS themselves.
Conclusion: To curtail residual malaria transmission, additional interventions able to target vectors escaping IRS should be prioritized.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6