Screening mosquito entry points into houses with novel long-lasting insecticidal netting to reduce indoor vector densities and mitigate pyrethroid-resistance

Objectives

The proposed proof-of-principle study in this area aims to address the protective gap of LLINs and IRS by evaluating the impact of housing improvement on indoor biting malaria vectors.

In an experimental hut study, preferred points of house entry will be investigated to determine if mosquito vectors enter houses through openings at ground level (under doors), roof level (through the eaves) or intermediate level (via windows). This is assessed by counting mosquitoes that enter so-called mosquito entry traps, which are installed behind each of these openings. These traps capture host-seeking mosquitoes that are attracted by a study volunteer sleeping inside the hut under an LLIN.

In a different study, mosquito entry points (windows and eaves) will be left unscreened in one hut, whereas the windows and eaves in two other huts will be screened with a novel durable polymer netting that is either untreated in one hut or chlorfenapyr-treated in the other. To evaluate whether the experimental huts differ in indoor mosquito densities overnight, host-seeking mosquitoes will be collected with standard mosquito traps inside the huts. 

The specific objectives are to:

• Assess preferential points of entry of different mosquito species into experimental huts reflecting local house construction,
• Determine if experimental huts with untreated window and eave screens reduce indoor mosquito densities, compared to unscreened experimental huts,
• Determine if experimental huts with chlorfenapyr-treated window and eave screens reduce indoor mosquito densities, compared to experimental huts with untreated screens,
• Determine if (delayed) mosquito mortality increases in experimental huts with chlorfenapyr-treated window and eave screens, compared to experimental huts with untreated screens,
• Evaluate the bio-efficacy of chlorfenapyr-treated mesh under field conditions.