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Table 1 A suggested generic plan for strengthening national or regional malaria vector monitoring platforms to incorporate assessment of essential behavioural phenotypes and their influence upon vector control impact, mosquito population dynamics and epidemiological outcomes[8, 28]

From: Characterizing, controlling and eliminating residual malaria transmission

1.

Expand and/or consolidate any existing national network of sentinel surveillance sites for physiological resistance of malaria vector mosquitoes to insecticides[33], ideally integrating these with similar platforms for other common mosquito-borne pathogens, such as lymphatic filariasis. Such sites should also overlap both with existing historical entomological study sites for which baseline legacy data is available, and with national platforms for assessing malaria burden through cross-sectional malaria indicator surveys or quality-assured facility-based surveillance.

2

Establish continuous longitudinal surveillance of mosquito population densities, and the transmission intensity each distinct population mediates, at sites where physiological resistance is monitored, so that the effects of vector control implementation upon seasonal and inter-annual trends can be assessed. Such surveillance platforms are essential to quantify residual transmission and distinguish between the fundamental limitations of an effective vector control strategy delivering incomplete but valuable and sustained impact versus an intervention failure, in the strict sense, which allows vector populations and malaria transmission to rebound (Figure 4)[28, 29, 31]. Such continuous, longitudinal surveys of malaria vector population dynamics have never been applied before at nationally representative scales. As such, affordable, practical community- or district-based mosquito trapping schemes, which are nevertheless resourced and managed by centralized national programmes, may need to be developed and evaluated[31, 120]. Given the reliance of scalable trapping schemes, especially those which are community-based, upon widely scattered, field-based personnel who may not always perform adequately[118, 119], it is also essential to establish quality assurance systems in which each of these sentinel sites is regularly and randomly re-surveyed by a centrally coordinated, specialist entomological team using the same trapping methods[31, 120]. Given the diversity of vector species and behaviours across the tropics, setting up such platforms for monitoring mosquito population dynamics may require initial pilot evaluations to select and calibrate suitable trapping methods or validate calibrations from elsewhere.

3.

Incorporate surveys of vector feeding and resting behaviours (using human landing catch by participants protected with drug chemoprophylaxis[128] and backpack aspirator/resting container/screening barrier sampling tools[129–131], respectively) into the quality assurance surveys described above under point 2, so that the extent to which each important vector species feeds on humans, feeds indoors, or rests indoors, can be quantified.

4.

Integrate monitoring of relevant human behaviours[16] and ecology, including resource use and livelihoods, vector control coverage and livestock ownership into national malaria surveys and/or entomologic surveillance platforms, so that their contributions to intervention limitations and failures can be assessed.

5

Where substantial transmission occurs indoors, experimental hut[132–134] facilities should be established at one or two sentinel sites where the most nationally-relevant vector species are abundant, so that the efficacy of vector control interventions can be assessed before and after their introduction[39].