[Epidemiology of malaria, the 1st world-wide endemia. Various observations]

Malaria is still the main worldwide endemia. More than one milliard of people live in some malaria infected areas. After having affected almost all parts of the continents, malaria, nowadays, is mainly limited to tropical and subtropical zones. There is not one single malaria but the disease offers four aspects according to the existence of four human plasmodial species, P. falciparum, P. vivax, P. ovale, P. malariae. P. falciparum is responsible for the more damageable effects on public health. It is the killing agent of tropical malaria. After a brief recall of the geographical distribution of the four human plasmodial species, the author reviews each link of the epidemiological chain: the pathogenic parasite, man as parasite reservoir, the anopheles as the vector in its relations with man and Plasmodium, receptive man regarding malarial infection, aspects of acquired immunity in the individual as well as in human groups of populations in endemic areas. These few up-to-date notes in malarial epidemiology may help to a better understanding of the endemicity levels, stable and unstable malaria, critic levels for transmission. A chapter deals with mathematical models for transmission. Rules for antimalarial control and reasons of the set backs of this control in tropical Africa are briefly reviewed.