Yellow fever is an acute viral hemorrhagic disease that is endemic in tropical areas of Africa and Latin America. It is caused by a virus of the Flavivirus genus of the Flaviviridae family and is transmitted to humans by the bites of infected Aedes and Haemagogus mosquitoes
. The virus is spread to people by the bite of an infected mosquito. Symptoms of yellow fever usually appear 3 to 6 days after the bite of an infected mosquito. In the initial phase, they include fever, muscle pain, headache, shivers, loss of appetite, and nausea or vomiting. For most patients, these symptoms disappear after 3 to 4 days. However, some patients enter a more toxic phase within 24 hours of recovering from initial symptoms. High fever returns and several body systems are affected, usually the liver and the kidneys. In this phase, people are likely to develop jaundice (yellowing of the skin and eyes, hence the name ‘yellow fever’), dark urine, and abdominal pain with vomiting. Bleeding can occur from the mouth, nose, eyes, or stomach. Half of the patients who enter the toxic phase die within 7 - 10 days
