3 stages of yellow fever

Q: Which of the following is NOT among the three stages of Yellow fever infection? (select one)

A) infection 

B) transmission

C) remission

D) intoxication 

Answer: B

Yellow fever is unique in the sense that it has a period of about 48 hours of remission between acute illness and severe yellow fever known as the period of intoxication. About 15 percent of patients enter the multi-stage organ failure stage (intoxication).

Infection period lasts for 3-4 days with viremia and consists of high fever, relative bradycardia, malaise, headache, photophobia, lumbosacral pain, pain in the lower extremities, myalgia, anorexia, nausea, vomiting, restlessness, irritability, dizziness, flushed skin, reddening of the conjunctivae and gums, and epigastric tenderness. Hepatomegaly with transaminitis may be present, which is a risk for an intoxication period. Another characteristic physical sign is that the tongue is characteristically red at the tip and sides with a white coating in the center. Instead of leucocytosis, leukopenia with relative neutropenia is common.

Period of intoxication is marked by the return of fever, prostration, nausea, vomiting, epigastric pain, jaundice, oliguria, and hemorrhagic diathesis. At this stage, viremia starts to disappear and antibodies appear in the blood. Eventually, Muti-system organ failure (MSOF) ensues.

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References:

1. Centers for Disease Control and Prevention (CDC). Fatal yellow fever in a traveler returning from Venezuela, 1999. MMWR Morb Mortal Wkly Rep 2000; 49:303.

2. Barnett ED. Yellow fever: epidemiology and prevention. Clin Infect Dis 2007; 44:850.

3. Tuboi SH, Costa ZG, da Costa Vasconcelos PF, Hatch D. Clinical and epidemiological characteristics of yellow fever in Brazil: analysis of reported cases 1998-2002. Trans R Soc Trop Med Hyg 2007; 101:169.

4. Kallas EG, D'Elia Zanella LGFAB, Moreira CHV, et al. Predictors of mortality in patients with yellow fever: an observational cohort study. Lancet Infect Dis 2019; 19:750.