Huang, W., J. Rodrigues, E. Bilgo, J. R. Tormo, J. D. Challenger, C. De Cozar-Gallardo, I. Pérez-Victoria, F. Reyes, P. Castañeda-Casado, E. J. Gnambani, D. F. Hien, M. Konkobo, B. Urones, I. Coppens, A. Mendoza-Losana, L. Ballell, A. Diabate, T. S. Churcher, and M. Jacobs-Lorena. 2023. delftia tsuruhatensis TC1 symbiont suppresses malaria transmission by Anopheline Mosquitoes. Science. 381: 533–540. DOI: https://doi.org/10.1126/science.adf8141
Abstract: Malaria control demands the development of a wide range of complementary strategies. We describe the properties of a naturally occurring, non–genetically modified symbiotic bacterium, Delftia tsuruhatensis TC1, which was isolated from mosquitoes incapable of sustaining the development of Plasmodium falciparum parasites. D. tsuruhatensis TC1 inhibits early stages of Plasmodium development and subsequent transmission by the Anopheles mosquito through secretion of a small-molecule inhibitor. We have identified this inhibitor to be the hydrophobic molecule harmane. We also found that, on mosquito contact, harmane penetrates the cuticle, inhibiting Plasmodium development. D. tsuruhatensis TC1 stably populates the mosquito gut, does not impose a fitness cost on the mosquito, and inhibits Plasmodium development for the mosquito’s life. Contained field studies in Burkina Faso and modeling showed that D. tsuruhatensis TC1 has the potential to complement mosquito-targeted malaria transmission control.
Notes: This article describes the findings of a study investigating the role of harmane, a compound secreted by Delftia tsuruhatensis TC1 bacteria, in the disruption of Plasmodium development in the midgut and the reduction of sporozoite prevalence in salivary glands of anopheline mosquitoes. The authors also describe the efficacious delivery of D. tsuruhatensis TC1 to larvae and adult mosquitoes in laboratory and field settings, indicating the versatility of potential deployment in the field. Studies like this show the importance of understanding the mosquito microbiome in variability seen in pathogen transmission in the laboratory and field.
[submitted by the Vector and Vector-Borne Disease Committee]