Yellow Fever

Yellow fever also called yellow jack is a mosquito-borne viral disease. Illness ranges in severity from an influenza-like syndrome to severe hepatitis and hemorrhagic fever. Yellow fever is caused by a zoonotic virus that is maintained in nature by transmission between nonhuman primates and mosquito vectors. In some situations, humans may serve as the primary host in the transmission cycle (“urban yellow fever”).

Yellow fever occurs only in Africa and South America. In South America sporadic infections occur almost exclusively in forestry and agricultural workers from occupational exposure in or near forests.

Symptoms of Yellow Fever 

The virus remains silent in the body during an incubation period of three to six days. There are then two disease phases. While some infections have no symptoms whatsoever, the first, "acute", phase is normally characterized by:

• fever, muscle pain (with prominent backache)
• headache
• shivers
• loss of appetite
• nausea and/or vomiting 

Often, the high fever is paradoxically associated with a slow pulse. After three to four days most patients improve and their symptoms disappear.

However, 15% enter a toxic phase within 24 hours. Fever reappears and several body systems are affected. The patient rapidly develops jaundice and complains of abdominal pain with vomiting. Bleeding can occur from the mouth, nose, eyes and/or stomach. Once this happens, blood appears in the vomit and faeces. Kidney function deteriorates; this can range from abnormal protein levels in the urine (albuminuria) to complete kidney failure with no urine production (anuria). Half of the patients in the "toxic phase" die within 10-14 days. The remainder recover without significant organ damage.

If you develop symptoms, consider consulting a doctor who focuses on international medicine or infectious diseases. A specialist may be able to recognize and treat your illness more quickly than a doctor who isn't trained in these areas can.

Yellow Fever Symptoms to Y

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