virus that belongs to the genus Flavivirus. It is related to West Nile, St. Louis encephalitis, and Japanese encephalitis viruses. Yellow fever virus is transmitted to people primarily through the bite of infected Aedes or Haemagogus species mosquitoes.

Aedes aegypti, the yellow fever mosquito originated in AFrica but can be found in tropical, temperate regions globally. Besides yellow fever, this mosquito is the vector for a majority of tropical fevers. Only female mosquitoes bites for blood, which is required for her eggs to mature. The lifespan of the Aedes is fairly short, lasting roughly two to four weeks. However, depending on the environment in which eggs were laid, they can remain viable for over a year. In the United States, the Aedes aegypti can be found throughout the southeast region but they are slowly declining due to competition with other mosquitoes.

Transmission

“Yellow fever virus has three transmission cycles: jungle (sylvatic), inter­mediate (savannah), and urban. The jungle (sylvatic) cycle involves transmission of the virus between non-human primates (e.g., monkeys) and mosquito species found in the forest canopy. The virus is transmitted by mosquitoes from monkeys to humans when humans are visiting or working in the jungle.In Africa, an intermediate (savannah) cycle exists that involves transmission of virus from mosquitoes to humans living or working in jungle border areas. In this cycle, the virus can be transmitted from monkey to human or from human to human via mosquitoes.The urban cycle involves trans­mission of the virus between humans and urban mosquitoes, primarily Aedes aegypti. The virus is usually brought to the urban setting by a viremic human who was infected in the jungle or savannah.” [19]

Clinical Manifestation

More than twenty percent of patients died after showing signs and symptoms of yellow fever. “After the bite of the infecting mosquito, it takes several days before symptoms appear” (Grunfeld, 2006). Due to the delay of symptoms, many of those infected spread the disease unknowing. “The disease characteristically began with high fevers, shaking chills that progressed to rigors, tachycardia, photophobia, conjunctival injection, petechiae, muscle pains, and headaches. The disease was punctuated by bleeding from the gums, epigastric discomfort, bilious vomiting, diarrhea, and melena. Jaundice, for which the disease was given its nickname “Yellow Jack,” subsequently developed. Following