Yellow fever is transmitted through the bite of a mosquito infected with a virus called flavivirus. Mosquitoes that transmit yellow fever are mainly found in Africa (Aedes species) and South America (haemagogus species). Both typically bite during the day and particularly at sunrise and sunset.
Symptoms of yellow fever include:
- muscle pain
- abdominal pain
- jaundice (yellow skin and eyes) when the virus attacks the liver
Hemorrhagic fever and hepatitis are side effects of yellow fever infection.
The yellow fever vaccine can prevent the disease. Travel to certain countries requires the traveler to be vaccinated against the disease no matter their country of origin documented by an International Certificate of Vaccination or Prophylaxsis. Some countries also require travelers to be vaccinated for yellow fever if they have traveled through a country where yellow fever is epidemic. Travelers without proof of vaccination may be denied entry into the country or be held in quarantine or vaccinated.