Yellow fever occurs only in Africa and South America. In South America sporadic infections occur almost exclusively in forestry and agricultural workers from occupational exposure in or near forests. 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. Yellow fever is a viral disease transmitted between humans by a mosquito. Yellow fever is a very rare cause of illness in travelers, but most countries have regulations and requirements for yellow fever vaccination that must be met prior to entering the country. General precautions to avoid mosquito bites should be followed. These include the use of insect repellent, protective clothing, and mosquito netting. Yellow fever vaccine is a live virus vaccine which has been used for several decades. A single dose confers immunity lasting 10 years or more. Adults and children over 9 months can take this vaccine. Administration of immune globulin does not interfere with the antibody response to yellow fever vaccine. This vaccine is only administered at designated yellow fever vaccination centers; the locations of which can usually be given by your local health department.