We have been studying malaria, which is one of the world’s three major infectious diseases, toxoplasmosis, and cryptosporidiosis, which are global zoonoses, using the techniques of molecular biology and virology. We are focusing on how the pathogens infect and propagate in the host cells.

Toxoplasmosis results in severe disease for mammals and birds including human. The anti-Toxoplasma drugs now induce dormant infection and cannot kill the parasite (図１). The way to discard the dormant parasites is needed. We established drug screening system which can inhibit both acute and dormant infection of Toxoplasma and succeeded in detecting ideal drugs.

Metal nanoparticles have the different physical and chemical characteristics compared with the bulk. It is caused by the extremely large surface area. They also have specific characteristics by the particle sizes, respectively. Moreover, they can produce reactive oxygen species that have the ability to kill infectious agents. We have reported that amino acid-capped metal nanoparticles（図２）can inhibit the growth of Toxoplasma.