Yellow fever is an acute viral infectious disease that is transmitted to humans through the bite of infected mosquitoes. Though many cases of yellow fever are mild and self-limiting, yellow fever can also be a life-threatening disease causing hemorrhagic fever and hepatitis (hence the term “yellow” from the jaundice it can cause). This viral disease occurs in tropical areas of Africa and South America, and each year there are an estimated 200,000 cases of yellow fever worldwide, leading to approximately 30,000 deaths. An increase in the number of cases of yellow fever in the last few decades has led to campaigns aimed at improving public awareness and disease prevention for this re-emerging infectious disease.
Yellow fever is thought to have originated in Africa and was likely brought to the Americas on ships during the slave trade. Several significant yellow fever outbreaks have occurred throughout history, with the first documented outbreak occurring in the Yucatan peninsula during the 17th century. During the late 18th century, a severe yellow fever outbreak struck New England and several North American port cities. The city of Philadelphia is thought to have lost about one-tenth of its population during the 1793 yellow fever epidemic, causing many notable figures in American politics to flee the city. The last major yellow fever outbreak in North America occurred in New Orleans in 1905.
The theory that yellow fever is transmitted by a mosquito was first introduced by a Cuban physician, Dr. Carlos Finlay, in the late 19th century. It was not until 1900, using earlier research from Dr. Finlay as a foundation, that U.S. Army Major Dr. Walter Reed and his team proved that yellow fever was in fact transmitted by mosquitoes. This ground breaking idea was instrumental in leading to the subsequent control of yellow fever in various regions. The virus responsible for yellow fever was later isolated in the late 1920s, and this breakthrough discovery allowed Max Theiler to later develop the first vaccine against yellow fever in the 1930s. This successful vaccine helped control and eliminate yellow fever from various countries in Africa and South America during the mid-20th century.
Countries where yellow fever is present.
|Central African Republic||Paraguay|
|Congo, DRC||Sao Tome & Principe|
|Cote d’Ivoire (Ivory Coast)||Sierra Leone|
|The Gambia||Trinidad & Tobago|
The diagram shows the general development stage of the malaria parasite in both the vector (mosquito and the host (human) (CLICK ON THE DIAGRAM TO ENLARGE)