In both mild and severe YF, the disease is characterized by two stages with a short intervening remission. The first stage of severe YF has a sudden onset of fever, chills, intense headache, lumbosacral back pain, myalgia, nausea and vomiting, conjunctival injection, dark urine, and bradycardia in relation to fever. A 12-24 hour remission usually ensues, and is characterized by decreased temperature, no headache, and general improvement. Terminal signs include progressive tachycardia, intractable hiccups, and shock. Mild YF resembles many other such febrile illnesses.
Treatment is supportive, i.e, control of fever, vomiting, dehydration, and pain.
W.B. Saunders Company. A decade of reemegence. Journal of the American Medical Association . Impact of yellow fever on the developing world. Advances in Virus Research .