Community effectiveness of indoor spraying as a dengue vector control method: A systematic review

The prevention and control of dengue rely mainly on vector control methods, including indoor residual spraying (IRS) and indoor space spraying (ISS). This study aimed to systematically review the available evidence on community effectiveness of indoor spraying

Community effectiveness of indoor spraying as a dengue vector control method: A systematic review

<div><p>Background</p><p>The prevention and control of dengue rely mainly on vector control methods, including indoor residual spraying (IRS) and indoor space spraying (ISS). This study aimed to systematically review the available evidence on community effectiveness of indoor spraying.</p><p>Methods</p><p>A systematic review was conducted using seven databases (PubMed, EMBASE, LILACS, Web of Science, WHOLIS, Cochrane, and Google Scholar) and a manual search of the reference lists of the identified studies. Data from included studies were extracted, analysed and reported.</p><p>Results</p><p>The review generated seven studies only, three IRS and four ISS (two/three controlled studies respectively). Two IRS studies measuring human transmission showed a decline. One IRS and all four ISS studies measuring adult mosquitoes showed a very good effect, up to 100%, but not sustained. Two IRS studies and one ISS measuring immature mosquitoes, showed mixed results.</p><p>Conclusions</p><p>It is evident that IRS and also ISS are effective adulticidal interventions against <i>Aedes</i> mosquitoes. However, evidence to suggest effectiveness of IRS as a larvicidal intervention and to reduce human dengue cases is limited–and even more so for ISS. Overall, there is a paucity of studies available on these two interventions that may be promising for dengue vector control, particularly for IRS with its residual effect.</p></div

Community effectiveness of pyriproxyfen as a dengue vector control method: A systematic review

<div><p>Background</p><p>Vector control is the only widely utilised method for primary prevention and control of dengue. The use of pyriproxyfen may be promising, and autodissemination approach may reach hard to reach breeding places. It offers a unique mode of action (juvenile hormone mimic) and as an additional tool for the management of insecticide resistance among <i>Aedes</i> vectors. However, evidence of efficacy and community effectiveness (CE) remains limited.</p><p>Objective</p><p>The aim of this systematic review is to compile and analyse the existing literature for evidence on the CE of pyriproxyfen as a vector control method for reducing <i>Ae</i>. <i>aegypti</i> and <i>Ae</i>. <i>albopictus</i> populations and thereby human dengue transmission.</p><p>Methods</p><p>Systematic search of PubMed, Embase, Lilacs, Cochrane library, WHOLIS, Web of Science, Google Scholar as well as reference lists of all identified studies. Removal of duplicates, screening of abstracts and assessment for eligibility of the remaining studies followed. Relevant data were extracted, and a quality assessment conducted. Results were classified into four main categories of how pyriproxyfen was applied: - 1) container treatment, 2) fumigation, 3) auto-dissemination or 4) combination treatments,–and analysed with a view to their public health implication.</p><p>Results</p><p>Out of 745 studies 17 studies were identified that fulfilled all eligibility criteria. The results show that pyriproxyfen can be effective in reducing the numbers of <i>Aedes spp</i>. immatures with different methods of application when targeting their main breeding sites. However, the combination of pyriproxyfen with a second product increases efficacy and/or persistence of the intervention and may also slow down the development of insecticide resistance. Open questions concern concentration and frequency of application in the various treatments. Area-wide ultra-low volume treatment with pyriproxyfen currently lacks evidence and cannot be recommended. Community participation and acceptance has not consistently been successful and needs to be further assessed. While all studies measured entomological endpoints, only two studies measured the reduction in human dengue cases, with inconclusive results.</p><p>Conclusions</p><p>Although pyriproxyfen is highly effective in controlling the immature stages of dengue transmitting mosquitoes, and–to a smaller degree–adult mosquitoes, there is weak evidence for a reduction of human dengue cases. More well designed larger studies with appropriate standardised outcome measures are needed before pyriproxyfen is incorporated in routine vector control programmes. Additionally, resistance to pyriproxyfen has been reported and needs investigation.</p></div

Flowchart of selection process.

<p>Flowchart of selection process.</p

Evidence table.

<p>Evidence table.</p

PRISMA flowchart of the selection process.

<p>PRISMA flowchart of the selection process.</p

Table of categories.

<p>Note that these categories are not mutually exclusive. Some studies are included in more than one category.</p

Summary of categorised results.

<p>Summary of categorised results.</p