Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes. The “yellow” in the name refers to the jaundice that affects some patients. A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days. Forty-seven countries in Africa (34) and Central and South America (13) are either endemic for, or have regions that are endemic for, yellow fever.
It is prevented by an extremely effective vaccine, which is safe and affordable. A single dose of vaccine is sufficient to grant sustained immunity and life-long protection against disease. A booster dose of the vaccine is not needed. The vaccine provides effective immunity within 10 days for 80-100% of people vaccinated, and within 30 days for more than 99% of people vaccinated.
It is difficult to diagnose, especially during the early stages. A more severe case can be confused with severe malaria, leptospirosis, viral hepatitis (especially fulminant forms), other haemorrhagic fevers, infection with other flaviviruses (such as dengue haemorrhagic fever), and poisoning. Polymerase chain reaction (PCR) testing in blood and urine can sometimes detect the virus in early stages of the disease. In later stages, testing to identify antibodies is needed (ELISA and PRNT).
Occasionally travelers who visit endemic countries may bring the disease to countries free from this disease. In order to prevent such importation of the disease, many countries require proof of vaccination against yellow fever before they will issue a visa, particularly if travelers come from, or have visited yellow fever endemic areas. Vaccine is recommended for people aged 9 months or older and who are traveling to or living in areas at risk for this virus. There’s no specific treatment for yellow fever. But getting a yellow fever vaccine before traveling to an area in which the virus is known to exist can protect you from the disease. Ask for more information to member of our team on vaccination program.