[The places of Mal'aria and the causes of malaria]

According to the Hippocratic medicine remittent and intermittent fevers were caused by bad air (mal'aria) and bad water of marshes, which produced miasmata affecting people living near these environments. This wrong theory was remarkably stable and persistent until the end of the last century, being in fact quite adequate to decribe the epidemiology of malaria in Mediterranean areas, where the transmission of the parasite depended on mosquitoes breeding mainly in marsh ecosystems. The theory was even reinforced with the spreading of severe malaria due to Plasmodium falciparum (more closely associated with warm marshy areas) and when a specific remedy, quinine, came into the picture, improving the distinction of malaria from other fever diseases. After the discovery of the true causes of malaria infection and transmission, scientific medicine developed completely new definitions of malarious environments based on their stratification in terms of transmission risk and several parameters were introduced which provide a measure of the vectorial capacity. This paper focus on the most relevant historical events that have brought to the present knowledge of malarious environments, examining at the same time the effectiveness and limits of the Hippocratic view on the etiology of malaria.