Toll-deficient Drosophila are resistant to infection by Pneumocystis spp.: additional evidence of specificity to mammalian hosts.

Pneumocystis spp. are significant pathogens in a variety of mammals. We tried to establish a Drosophila model of pneumocystosis using either P. murina or P. carinii. Whereas the pathogens were competent in susceptible mice, no infection could be established even in corticosteroid-treated Toll-deficient flies. This further substantiates the tropism described for mammalian hosts.