With no vaccine or treatment for chikungunya, the primary means of controlling the outbreak that took place in 2005-2006 on Réunion Island was to control the mosquitoes responsible for the transmission of this disease. Alongside these mosquito control operations, recommendations encouraging the use of mosquito nets or insecticide-impregnated clothing were issued by several organisations. Within this context, the Agency was asked to clarify the conditions for use of these protective measures and to assess their toxicity with repeated use in the short, medium and long terms.

To be effective and sustainable, insecticide-based vector control must be based on the alternate use of active substances with various modes of action, in order to limit the development in these insect vectors of resistance to insecticides. To identify active substances potentially interesting for use in vector control, ANSES undertook extensive, coordinated research into the insecticides used for vector control, which led to 32 substances being identified. ANSES then selected a reduced number of adulticide or larvicide compounds that could potentially be used in the medium term and whose use would comply with the European regulations, and carried out risk assessments on four of them.