An acute, infectious, hemorrhagic viral disease. It is characterized by sudden onset of fever, bradycardia, and headache; with jaundice and hemorrhaging occuring in severe cases.

  1. Sudden onset of fever, slow pulse, and headache. Severe cases progress to intense albuminuria (excessive amounts of the protein albumin in the urine), jaundice, and hemorrhage--in particular, hematemesis, or a "black" vomit of blood.
  2. This stage lasts 2 to 5 days, and is characterized by sudden onset of a fever of 102 to 104 F.
  3. Other symptoms include: flushed face, injected eyes, nausea, vomiting, constipation, epigastric distress, headache, muscle pains (especially in the neck, back, and legs), severe prostration, restlessness, and irritability.