Moiroux Nicolas, Gomez M. B., Pennetier Cédric, Elanga Ndille Emmanuel, Djenontin Armel, Chandre Fabrice, Djegbe I., Guis H., Corbel Vincent
Source
Journal of Infectious Diseases, 2012,
206 (10), p. 1622-1629 ISSN 0022-1899
Background. Behavioral modification of malaria vectors in response to vector control methods is of great concern. We investigated whether full coverage of long-lasting insecticide-treated mosquito nets (LLINs) may induce a switch in biting behavior in Anopheles funestus, a major malaria vector in Africa. Methods. Human-landing collections were conducted indoor and outdoor in 2 villages (Lokohoue and Tokoli) in Benin before and 1 year and 3 years after implementation of universal LLIN coverage. Proportion of outdoor biting (POB) and median catching times (MCT) were compared. The resistance of A. funestus to deltamethrin was monitored using bioassays. Results. MCT of A. funestus switched from 2 AM in Lokohoue and 3 AM in Tokoli to 5 AM after 3 years (Mann-Whitney U test, P < .0001). In Tokoli, POB increased from 45% to 68.1% (odds ratio = 2.55; 95 confidence interval = 1.72-3.78; P < .0001) 1 year after the universal coverage, whereas POB was unchanged in Lokohoue. In Lokohoue, however, the proportion of A. funestus that bites after 6 AM was 26%. Bioassays showed no resistance to deltamethrin. Conclusions. This study provides evidence for a switch in malaria vectors' biting behavior after the implementation of LLIN at universal coverage. These findings might have direct consequences for malaria control in Africa and highlighted the need for alternative strategies for better targeting malaria vectors.
