(Collaborators: Sébastien Breurec, Ionela Gouandjika,Thierry Frank, Caroline Martin (IP Bangui), Petulla bata, Jean Gody (Complexe pédiatrique Bangui), Tamara Giles-Vernick, Loic chartier, Muriel Vray (IP Paris)). Funding : The fondation Total. Diarrhea ranks as the world’s third most deadly infection in children, claiming some 2.2 million lives each year, of whom two million are under five years old. In the absence of laboratory tests, the presumptive treatment leads to an overestimation of possible bacterial diarrheas and of the overuse of antibiotic treatments, which can lead to the emergence of antibiotic resistant strains. In CAR, childhood diarrhea constitutes one of the most important public health problems, with a global prevalence estimated at 19%, and reaching 30% among children between 12 and 23 months old.This study, which will include 600 HIV-negative children, hospitalized for severe diarrhea and a control group of 600 children, matched by sex, age, and neighborhood of residence, has the following primary objectives:1) Identify the pathogens implicated in diarrhea;2) Measure antibiotic resistance of different isolated bacterial strains;3) Study over the short term the characteristics, evolution and sequellae of severe diarrhea;4) Identify the risk factors (socio-economic, alimentary, environmental) associated with severe diarrhea;5) Evaluate using an anthropological approach the practices and local concepts surrounding childhood diarrhea, as well as the treatment and feeding of diarrheal children.All cases will undergo clinical examination, consisting of anthropometric measures, parasitological, virological, and bacteriological analyses of stool samples, and blood testing. For the controls, anthropometric measurements and a stool exam will be carried out. Expected results This study will reinforce the knowledge of the epidemiology and etiologies of severe childhood diarrhea. In addition, it will also improve knowledge of the characteristics, evolution and sequellae of diarrhea that necessitate hospitalization. The analysis of antibiotic resistance of isolated strains and genotypical and phenotypical factors of virulence will help to strengthen algorithms for the care management of patients. The anthropological approach, which seeks to identify the understandings and practices of mothers confronted with diarrheal children, should also assist in improving the management of children’s care.