Yellow fever is a viral disease transmitted between humans
by mosquitoes. The disease occurs only in parts of Africa and
Symptoms of the disease range from fever, chills, and headache
to abdominal pain, vomiting, and jaundice. There may appear to
be a brief recovery before the disease progresses to more severe
complications including internal bleeding, and kidney or liver
failure. Death occurs in about 5% of those infected. There is
no medical treatment apart from keeping the fever down and avoiding
Endemic yellow fever areas
There are countries in Africa and South America that have endemic
yellow fever .
In South America, the "endemic yellow fever zone" includes:
Panama, Columbia, Venezuela, Guyana, Suriname, French Guiana,
western Ecuador, western Peru, western Bolivia, eastern Brazil.
In these countries sporadic infections occur almost exclusively
to forestry and agricultural workers who are exposed occupationally
in or near forests.
In Africa, the "endemic yellow fever zone" includes:
Angola, Tanzania, Zaire, Kenya, Uganda, Somalia, Ethiopia, southern
Sudan, southern Sudan, southern Chad, southern Niger, southern
Mali, Central African Republic, Congo, Gabon, Rio Muni, Cameroon,
Nigeria, Benin, Togo, Ghana, Burkino Faso, Ivary Coast, Liberia,
Sierra Leone, Guinea, Guinea-Bissau, Gambia, Senegal, Sao Tome
and Principe Islands.
In Africa the virus is transmitted in three geographic regions:
principally and foremost, in the moist savanna zones of West and
Central Africa during the rainy season, secondly, outbreaks occur
occasionally in urban locations and villages in Africa, and finally,
to a lesser extent, in jungle regions.
General precautions to avoid mosquito bites should be followed.
These include the use of insect repellent, protective clothing,
and mosquito netting. These mosquitoes bite mainly during the
evening and morning hours.
Yellow fever certificate requirement
Although yellow fever is a very rare cause of illness in travelers,
most countries require a certificate from travelers arriving from
infected areas. Some countries in Africa require evidence of vaccination
from all entering travelers. Vaccination is also recommended for
travel outside the urban areas of countries which do not officially
report the disease, but which lie in the yellow fever endemic
zone. Some countries require an individual, even only in transit,
to have a valid International Certificate of Vaccination if he
or she has been in countries either known or thought to harbor
Yellow Fever virus. Such requirements may be strictly enforced,
particularly for persons traveling from Africa or South America
Yellow fever vaccination certificate
Yellow fever vaccine is a live virus vaccine. A single dose confers
long-lived immunity lasting 10 years or more. This vaccine has
been used for several decades and has a very low rate of adverse
reactions associated with it. After immunization an International
Certificate of Vaccination is issued and is valid 10 days after
vaccination to meet entry and exit requirements for all countries.
The Certificate is good for 10 years. You must take the Certificate
One dose of yellow fever vaccine may be administered to adults
and children over 9 months of age. This vaccine is only administered
at designated yellow fever centers, usually your local health
department. Consult your local health department for yellow fever
vaccination sites near you. If at continued risk of yellow fever
infection, a booster dose is needed every 10 years.
Travelers who have a medical reason not to receive the yellow
fever vaccine should obtain a medical waiver. Most countries will
accept a medical waiver for persons with a medical reason not
to receive the vaccine (e.g. infants less than 4 months old, pregnant
women, persons hypersensitive to eggs, or those with an immunosuppressed
condition.) In such cases, obtain the waiver in writing from consular
or embassy officials before departure. A physician's letter clearly
stating the medical reason not to receive the vaccine might be
acceptable to some governments. It should be written on letterhead
stationery and bear the stamp used by a health department or official
immunization center to validate the International Certificate
of Vaccination. Check embassies or consulates for specific waiver