Yellow fever is a potentially deadly virus in the flavivirus genus, just like Zika, Dengue and West Nile. After an Aedes aegypti or Haemagogus mosquito bites an infected monkey or human and transmits yellow fever to a new host, the virus lurks in the body for three to six days before symptoms arise. While symptoms like headaches, nausea, muscle pain and occasional vomiting may disappear within a week, about 15 percent of people enter a second stage of symptoms. This unlucky group experiences a high fever, bleeding from the nose, eyes and mouth, kidney failure, and liver damage, which eventually leads to the yellowing skin the virus is known for. Hospitalization is necessary for patients in this second stage and death occurs in about half of them, bringing the average death rate of yellow fever to about 7.5 percent.