Wolbachia pipientis: an expanding bag of tricks to explore for disease control.

Wolbachia pipientis are maternally inherited, endosymbiotic bacteria that are widespread among insects. Two recent studies have demonstrated that Wolbachia inhibits the ability of medically significant pathogens, including filarial nematodes, dengue virus and Plasmodium to form infections in the mosquito vector, Aedes aegypti. We highlight the added value of these traits for Wolbachia based biocontrol strategies and evaluate the evidence for the idea that the insect immune response is responsible for the pathogen inhibition.