the audio explanation from the CDC
Yellow fever is a flavivirus that can cause severe symptoms in travelers
There are 200,000 cases of yellow fever per year with 30,000 deaths.
There are 3 modes of transmission of this virus by mosquito: sylvatic,
intermediate and urban. The sylvatic cycle occurs in tropical rain
forests. The virus is found in monkeys who mosquitoes bite and spread
to people. The intermediate cycle occurs in the humid / semi humid
savannahs of Africa. Both humans and monkeys are reservoirs for
yellow fever. The urban cycle occurs when immigrants infected will
introduce the virus into a population where mosquitoes that were
formerly virus free pick it up.
Many countries require a yellow-
fever certification of vaccination from arriving travelers to protects that country from travellers who may be bringining in yellow fever. Resident Aedes egypti mosquitoes may become infected with the virus and cause an urban yellow fever outbreak.
In other countries or regions within countries yellow fever may be recommended for travelers based on an assessment of their actual risk from their itinerary
Symptoms of yellow fever, range from none, to full blown cases.
The incubation period after being bitten is 3-6 days followed by
fever, headache, muscle aches, and protein in urine. Usually a slow
pulse with fever is noted and abdominal tenderness. After 3-5 days
people get better or may deteriorate with liver and kidney failure,(causing
the yellow jaundice), abdominal pain and bleeding.
Fatality has been 50% for adults, 70% for children. No treatment
is other than supportive is available.
The yellow fever vaccine can only be given through specialized clinics.
Yellow Fever must be kept refrigeratedand be given to a patient within
one hour of being reconstituted.
It is a live vaccine that may cause 1-3 days of muscle aches, low-grade
fever or malaise (flu symptoms), but is effective after 7-10 days.
These side effects are rare and sometimes happen within the first
2 weeks after vaccination. It is not given to children under 9-12
months (unless an overwhelming need), immune compromised individuals
and pregnant women. The yellow fever certificate should be kept
with the traveler's passport and is valid for 10 years
some very severe side effects have been noted in individuals with
chronic illnesses including death. It is important that yellow fever
immunization be given appropriately to the people who really do
need it and also not to people who could become ill from it.
for Disease Control http://www.cdc.gov/travel/diseases/yellowfever.htm
Health Organization http://www.who.int/csr/disease/yellowfev/en/
American Health Organization
in the Medical Arts and Sciences that Arise During Wartime
discussion on Dr Walter Reed and Yellow Fever