infectious diseases
Yellow Fever
Symptoms and Signs of Yellow Fever
Infection ranges from asymptomatic or mild symptoms in most people to a hemorrhagic fever with a case fatality rate of 30 to 60% (Centers for Disease Control and Prevention [CDC]:Yellow Fever; Symptoms, Diagnosis, & Treatment). Incubation lasts 3 to 6 days. Onset is sudden, with fever of 39 to 40°C, chills, headache, dizziness, and myalgias. The pulse is usually rapid initially but, by the 2nd day, becomes slow for the degree of fever (Faget sign). The face is flushed, and the eyes are injected. Nausea, vomiting, constipation, severe prostration, restlessness, and irritability are common. Mild disease may resolve after 1 to 3 days. However, in moderate or severe cases, the fever falls suddenly 2 to 5 days after onset, and a remission of several hours or days ensues. The fever recurs, but the pulse remains slow. Jaundice, extreme albuminuria, and epigastric tenderness with hematemesis often occur together after 5 days of illness. There may be oliguria, petechiae, mucosal hemorrhages, confusion, and apathy. Disease may last>1 week with rapid recovery and no sequelae. In the most severe form (called malignant yellow fever), delirium, intractable hiccups, seizures, coma, and multiple organ failure may occur terminally. During recovery, bacterial superinfections, particularly pneumonia, can occur. 