Yellow Fever
Yellow Fever is a virus 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 that travelers' visiting their country produce a certification of Yellow Fever vaccination before entering the country. It is the travelers' responsibility to be vaccinated against yellow fever so that they will not introduce the Yellow Fever virus into their country, setting up a urban cycle.

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 up to 50% for adults, and 70% for children. No treatment other than support is available. The Yellow Fever vaccine can only be given through specialized clinics. Yellow Fever must be kept frozen and be given to a patient within one hour of being thawed and 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 usually not to pregnant women. The Yellow Fever certificate should be kept with the traveler's passport and is valid for 10 years. The vaccine itself may be effective for more than 10 years .

For your reference a downloadable version of this text can be found at this link.
Front Page - Back Page