Discriminating concentrations of insecticides for monitoring resistance in Culex quinquefasciatus and Culex tarsalis: report of a multi-centre laboratory study and WHO expert consultations

Overview

The document presents the outcome of a WHO multi-centre study (2022–2023) performed by five laboratories in different WHO regions with six insecticides and the WHO expert consultations that made recommendations to WHO on insecticide discriminating concentrations (DCs) for monitoring insecticide resistance in Culex quinquefasciatus and Cx. tarsalis. It also proposes further research to test the new DCs for Culex spp. in other settings and conditions, and to collect evidence from the national disease control programmes and share them with WHO for further assessment and revision of the DCs if required.

The current edition of the WHO manual for monitoring insecticide resistance in mosquito vectors and selecting appropriate interventions will be revised in due course using the recommendations made to WHO including for the new DCs for Culex spp.

The report will be useful to the national vector-borne disease control programmes and the research community for insecticide resistance monitoring, and to academia, the pesticide regulatory agencies and the pesticide industry for further innovation in this area and to address the research questions.

Please send your suggestions and comments to VVE@who.int indicating the title of the report and the relevant section and page.