University of Geneva - Faculty of Medicine

. One of the fundamental questions in parasitology is to understand how a eukaryotic cell can penetrate, survive and replicate within another eukaryotic cell. Acquisition of such basic knowledge is considered a prerequisite to design strategies of intervention to prevent or cure infectious diseases. Members of Apicomplexa are of considerable medical and veterinary significance, being responsible for a wide variety of diseases in human and animals, including malaria, toxoplasmosis, cryptosporidiosis and coccidiosis. As obligate intracellular, apicomplexan parasites actively cross biological barriers, penetrate host cells and egress by using a unique and conserved mode of gliding motility.To tackle this complex question, we have chosen Toxoplasma gondii, an obligate intracellular parasite that infects almost all mammals as well as birds, and invade virtually any nucleated cell. It is the causative agent of toxoplasmosis, which is usually symptomless but can lead to serious complications in case of congenital infection, and to fatal cerebral toxoplasmosis in severely immuno-compromised patients. Our initial efforts were dedicated toward the development of methodologies to genetically manipulate this organism and more recently we have established an inducible system to study the function of essential parasite genes. We are studying the molecular mechanisms involved in motility, host cell attachment and invasion and the strategies allowing intracellular survival.