Despite a global decrease in incidence and mortality thanks to the implementation of integrated control measures, most of sub-Saharan Africa continues to carry a high share of the global malaria burden. Moreover, in some sub-Saharan countries there has been an increase in cases, even in presence of large-scale Long-Lasting Insecticide Net distribution (LLIN, the major vector control intervention), possibly associated with a shift towards exophilic malaria vector species and/or an increase of outdoor biting behavior. In Burkina Faso in particular, four major Anopheles vectors are responsible of most malaria burden: A. coluzzii, A. gambiae, A. arabiensis, and A. funestus. Their ecological features and genetic plasticity are major threats to an effective control of malaria in the country. Moreover, the decrease of LLIN effectiveness also due to resistance developed by malaria vectors against pyrethroid insecticides, the most important class of insecticides used to impregnate mosquito nets.
Data collected in the Burkinabe village of Goden during the rainy season 2011 by our research group show that the protective performance of LLINs can be weak despite the high coverage: low values of human blood index (5%) in mosquito vectors collected indicate a high risk of transmission.
We aim to analyze mosquitoes already available from a parallel survey conducted in a different village, to confirm the LLIN-induced ¿low HBI/high SR¿ scenario and thus provide a possible explanation of such phenomenon. To achieve this goal, we will: i) taxonomically identify malaria vectors to assess their resting behavior, ii) define their infectivity and feeding preferences, and thus their role in transmission, iii) determine the frequency of pyrethroid resistance alleles. Integrating ecology and epidemiology, we aim to give a wider perspective on factors influencing malaria transmission, useful for the implementation of efficient control strategies.
