What organ or system does yellow fever affect?

Yellow Fever: has an incubation period of 3 to 6 days. Sx's of acute phase can include: fever, nausea, vomiting, headache,light sensitivity, muscle pain (back & knees), anorexia, dizziness & shivering. These sxs usually resolve after 3 to 4 days in 85% of patients. However 15% may have remission of sx's followed by return of high fever with abdominal pain, bloody emesis / stool, jaundice, slow heart rate, as >