[Acute infectious diarrhea].

Acute infectious diarrhea has various causes: bacterial diarrhea with invasive or toxigenic mechanisms, especially frequent in hot regions and in travelers; viral diarrheas, frequent and cosmopolitan in children but also adults; and parasitic diarrhea, less frequent, and generally in subtropical areas. The major concerns involve the risk of complications, essentially dehydration and malnutrition, especially in vulnerable patients: young children, the elderly, and patients with immunosuppression, for whom rehydration is urgent. Diagnosis of diarrhea requires clinical assessment and history: underlying illnesses, severity of symptoms, presence and extent of dehydration and other clinical symptoms, travel history, known outbreaks, and pathogenic mechanism (invasive or toxigenic).