Yellow FeverTiffany S. & Tonya C.

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Multiple Yellow Fever Viruses at 234,000x mag.

Description of virus that causes the disease.

  • Caused by a "flavivirus" called Yellow Fever
  • (flavus meaning yellow in Latin)
  • Group called Flaviviridae, carried by antropods (mosquitoes, ticks etc.)
  • 40-60 nanometers wide
  • enveloped RNA virus
  • consists of a single strand of RNA

Viral Specificity:

  • Main target is the liver
  • Also affects the heart, kidneys, glands, adrenal glands
  • Skeletal muscle tissue affected
  • Hosts are humans (Urban yellow fever) or monkeys (Jungle yellow fever)
  • After bitten by infected anthropod the virus enters through the skin
  • Travels through the blood stream spreading to the organs
  • Liver failure occurs, heart beat slows and adrenal glands stop functioning

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Symptoms and progression of the disease:

  • Incubation period of 3-6 days
  • Symptoms start abruptly (5-6 days) including fever, headache, back pain, extreme exhaustion, nausea, and vomiting.
  • Second phase symptoms such as extreme fever, jaundice (due to liver damage), liver & kidney failure, and bleeding in the mouth, skin, and gastrointestinal tract
  • After 3-4 days of symptoms the host usually begins healing lasting hours to days
  • Then the "Yellow Phase" including severe symptoms such as liver inflammation, jaundice, black vommit, high fever, hemorrhaging, confusion, bleeding into the skin, coma & death
  • If the host recovers from the "Yellow Phase" they go into remission
  • Undergoes a lytic cycle in both the mosquito and human body (liver cells)

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Symptoms of Yellow Fever



Common Methods of Transmission:

  • Transmitted through infected mosquitoes

  • Not passed from human to human
  • Three different infectious cycles
  • Urban cycle:
  • Human infected in densely populated areas
  • one or many infected mosquitoes pass it to large numbers of humans
  • common cause of yellow fever outbreaks
  • Sylvatic cycle:
  • in the jungle, monkeys
  • infected monkeys pass the virus to other mosquitoes
  • can rarely occur to humans working in rainforest
  • Savannah cycle:
  • can infect humans or monkeys
  • in humid areas, most common in Africa
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Treatment and Prevention:

  • Yellow fever vaccine exists
  • Avoidance of mosquito bites (covering of exposed skin/repellent)
  • Rest & fluids is crucial to reduce symptoms
  • Hospitalization
  • No cure exsists once acquired
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Vaccine being given


Miscellaneous:

  • 90% of cases occur in Africa, 10% in South America
  • Originated in Africa, spread to West Africa
  • Carried to Yucatan by ship in 1648
  • For hundreds of years people had no idea what caused Yellow Fever
  • Major outbreaks in South America
  • Carried to United States (mainly Philadelphia)
  • Caused George Washington to flee
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Resources accessed:

Author: Mary T. Busowski

Title of article: Yellow Fever

Url: http://emedicine.medscape.com/article/232244-overview

Date: April 17, 2009

Author: Judy Arbigue
Title of article: Yellow Fever - The Disease & Symptoms
Url: http://www.suite101.com/content/yellow-fever-a12900
Date: February 7, 2007

Author: Mama's Health copyright
Title: Yellow Fever
Url: http://www.mamashealth.com/yellow.asp
Date: Oct. 23, 2010