During the first phase of ESSENTIALS, we developed a suite of tests designed to understand how mosquitoes interact with bednets that are treated with insecticides.
Different insecticides, especially when combined with additional active ingredients, can change the way that mosquitoes behave at the bednet when attempting to feed from humans; for example, a net treatment that is very irritant to mosquitoes may mean that mosquitoes do not spend as long trying to take a blood meal, or that when they do feed, the meal is incomplete. It also means that they may not stay in contact with the net long enough to receive a full lethal dose. Our tests allow us to characterise the effects of each type of bednet on different vector populations, and therefore understand which nets might be the most suitable for use in various settings.
To create our test suite, the room-scale tracking system developed in earlier projects was complemented by a range of smaller benchtop bioassays. The tests are designed to extract as much data about mosquito behaviour as possible whilst being simple enough to be implemented in both full-scale laboratories and in temporary field stations that might be set up close to areas in which bednets are deployed.
Following every test, each mosquito is monitored as part of an extended follow-up. This allows the identification and characterisation of any delayed or sub-lethal effects that the chemistries might have.