Yellow fever is an illness carried by mosquitoes, usually in tropical or subtropical countries. People with yellow fever often experience a headache, fever, chills, and nausea, and most recover within a week of symptoms. However, some patients experience a recurrence of symptoms, in addition to liver and kidney problems. When the liver starts to malfunction, the skin begins to turn yellow because of jaundice, hence the term “yellow fever.”
There is a vaccine for yellow fever that can prevent an infection, and many countries require this vaccine for travelers entering. Other countries highly recommend vaccination before someone travels to a country where yellow fever is endemic. Yellow fever is not yet a problem in Asia, but because incidence of the illness has been increasing in recent years, some Asian countries require vaccination for travelers.
Approximately nine out of ten cases of yellow fever occur in sub-Saharan Africa. Countries with the highest occurrence of yellow fever and in which vaccination is highly recommended include Ethiopia, Sudan, South Sudan, Chad, Niger, Nigeria, Cameroon, Central African Republic, Benin, Togo, Ghana, Liberia, Cote d’Ivoire, Burkina Faso, Mali, Mauritania, Senegal, Gambia, Guinea-Bissau, Sierra Leone, Guinea, Uganda, Kenya, Democratic Republic of Congo, Republic of Congo, Gabon, Sao Tome, and Principe, Rwanda, Burundi, and Angola. Other African countries in which yellow fever occurs but not as severely include Eritrea, Djibouti, Somalia, Tanzania, and Zambia.
Yellow fever also occurs in many parts of South America. Countries with a high incidence of yellow fever and in which vaccinations are highly recommended include Panama (which is technically part of North America but forms a land bridge between North America and South America), Venezuela, Colombia, Trinidad, Guyana, Ecuador, Suriname, French Guiana, Peru, Bolivia, Paraguay, Brazil, and Uruguay.
Yellow fever kills about 30,000 people every year, but this number is likely underreported because of cases that occur in conflict zones and severely impoverished areas. Cases are increasing for many reasons. One reason may be that there is better reporting of incidents that have been occurring all along, but there are other reasons, as well. These include global warming increasing the habitat of mosquitoes that carry the yellow fever virus; increased urbanization in which people live in more densely populated areas, thereby further enabling a rapid spread of illness; and growing population in areas in which yellow fever is endemic.
There is currently no treatment of yellow fever other than addressing the symptoms. The best treatment is prevention through a vaccine.