Yellow fever is an acute viral hemorrhagic disease of the body. It is transmitted by the bite of a female mosquito and is generally found in the tropical and subtropical areas of South America and Africa. The presence of the disease is not known to be in Asia at all. Known hosts of the virus include primates and several different species of mosquitoes. It is believed that the disease originally came from Africa after being introduced to South America from the slave trade of the 16th century. Beyond the 17th century, it has been noted that there have been many epidemics of the disease within the Americas, Africa, and Europe itself. By the 19th century, yellow fever was regarded to be one of the most dangerous infectious diseases of its time.
Symptoms of yellow fever can be found in chills, fever, anorexia, muscle pain, nausea, and headache. Generally these symptoms should subside after a few days have passed. Sometimes patients deal with a toxic phase where there is liver damage and jaundice, eventually leading to death if it is not treated or if the individual is not able to fight off the infection. Since there is a large bleeding tendency during this time, yellow fever is considered to be one of the numerous hemorrhagic fevers. The World Health Organization estimates that yellow fever is responsible for around 200,000 illnesses and 30,000 deaths on a regular basis when dealing with populations who have not been vaccinated. 90% of these infections are said to occur within Africa.
An effective vaccine against the infection of yellow fever has existed since around the time of the middle of the 20th century. Some countries which are known to have a prevalence of this infection require for travelers to get vaccinated before they can visit in the area. Vaccination is focused on as being very important because there is no therapy that is known for treatment of the infection when it has been contracted. Unfortunately, since around the 1980s, there has been a great increase in the amount of cases that have been contracted of yellow fever. For this reason, it is considered to be emerging again and is believed to gradually be becoming a threat for some populations. It is also believed that it is re-emerging because of the amount of war and disruption that has occurred within several African nations. Ultimately, if people are able to get vaccination, it is believed that they should be able to handle being infected with the disease without any threats of complications.