A pilot study on isolation of Asaia and detecting its co-presence with Plasmodium falciparum in two major malaria vectors in Senegal

Abstract

The declining of malaria creates the opportunity to accelerate its elimination. However, the elimination program is threatened by the spread of insecticide resistance among Anopheles (An.) mosquitoes, stressing the urgent need for new vector control strategies. Recent evidence of stable infection of anopheles’ symbionts that could affect the development of Plasmodium parasites within mosquitoes, has paved the way for the use of such organisms to target and control malaria vector populations. We have isolated a new Asaia strain from a wild population of Anopheles gambiae s.l. and, for the first time, from natural population of Anopheles funestus, and insectary colony of Anopheles coluzzii. The new anopheline strain has been named Asaia (A.) aff. bogorensis GD01 because of its close relationship with A. aff. bogorensis isolated from plant flowers. We highlighted an antagonistic effect of A. aff. bogorensis GD01 on the sporogonic development of Plasmodium falciparum within the two major malaria vectors (An. gambiae and An. funestus) in Senegal. The putative impact of A. aff. bogorensis GD01 infection on the P. falciparum sporogonic development offers an opportunity for new malaria vector control approaches that can be added to the limited arsenal required to fulfil the World Health Organization (WHO) recommendations for searching new tools to achieve malaria elimination goal. Although this is an innovative and promising malaria control tool, more investigations are required to better characterize Asaia vs. Plasmodium interactions, before any Asaia¬-based intervention. This is required to ensure their safe use as an alternative or complementary vector control strategy to achieve malaria elimination goal. Key words: Asaia, Plasmodium falciparum, malaria, Anopheles gambiae, Anopheles funestus, Senegal.