Edmond Sergent, supported by a distinguished team of colleagues, directed the Pasteur Institute of Algeria for over 60 years, from 1900 to 1963. As a student of Emile Roux, Sergent had received a Pasteurian training. His institute devoted extensive study to malaria. Sergent defined the concept of prevention and extended it to other pathologies. For many years, the Institute persevered in carrying out successful antimalarial campaigns such that Algeria was freed of the disease. In 1916-1917, Sergent and his brother were called upon to organise anti-malarial efforts for the Armée d'Orient. By way of systematic and energetic curative and prophylactic measures, they were able to eradicate the disease. In 1908, the Sergent brothers were the first to discover the role of the louse in the transmission of another disease, relapsing fever. The Pasteur Institute team also discovered the sand fly vector which transmits the parasite causing leishmaniasis. The Sergents found a new form of oculonasal myiasis, called "Thimni". In addition, they led effective campaigns against tuberculosis based on BCG vaccination administered throughout Algeria. The Pasteur Institute of Algeria conducted important research in plant and animal diseases. For example, they detected a trypanosome agent causing dromedary "debab", as well as its vector, the horsefly. They also studied in depth bovine piroplasmosis, which causes widespread and destructive disease, and demonstrated the role of the tick in promoting transmission generally. Their work in botany included the discovery that a Fusarium-type fungus was the causal agent for "baïoudh", the main disease of date palms. They also demonstrated the basic role of the fruit fly in alcoholic grape fermentation.