Yellow Fever is a viral infection that causes damage to the liver, kidney, heart and gastrointestinal tract. Major symptoms may include sudden onset of fever, yellowing of the skin (jaundice) and hemorrhage. It occurs predominately in South America, the Caribbean Islands and Africa. The disease is spread through bites of infected mosquitos. Incidence of the disease tends to increase in the summer as the mosquito population increases, and it occurs year round in tropical climates.
Yellow Fever has two cycles: the sylvan cycle in which mosquitos primarily spread the disease among forest-dwelling primates, and the urban cycle in which the infection is spread from human to human.
The symptoms of Yellow Fever are the sudden onset of fever and chills along with headache, backache, generalized pain, nausea, vomiting, flushed face and infection of the inner eyelid. The fever usually disappears after three days, reappearing several days later with new symptoms of jaundice, bleeding gums, soft palate hemorrhages, and the vomiting of blood (black vomit). The patient may go into shock during this phase.
Yellow Fever may also appear in a mild form with symptoms resembling influenza, malaria, dengue fever or typhoid. In this case, the fever usually lasts less than one week.
Yellow Fever is caused by a virus spread by the bite by an infected mosquito. Initially, a mosquito acquires the disease by ingesting the blood of an infected host. The mosquito then transmits the infection to its next bite victim.
Yellow Fever affects males and females equally. People living in semitropical or tropical climates are at risk unless they are vaccinated against this infection. People in southern areas of the United States, living near marshes and swamps may be at risk during the summer months. However, most cases of Yellow Fever occur in Africa and South America.
The treatment of Yellow Fever is symptomatic and supportive. Preventative measures consist of mosquito control and a vaccine that prevents development of the infection. Immunity from a vaccination usually develops after 10 days and lasts for more than 10 years. In some cases, side effects associated with vaccination may occur five to 10 days later. These side effects affect approximately 5 percent of individuals receiving immunization and may include headache, fever, and/or aching muscles.
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