Yellow Fever (V)

What environmental conditions exist that the yellow fever virus/potential pathogen deals with?

Yellow fever virus depends on Aedes aegypti mosquitoes, which develop in shallow standing water found in outdoor containers such as pots, water barrels, and old tired.

The virus circulates in jungle environments with monkey reservoirs and regions where mosquitoes thrive, especially warm climates.

How does the Yellow fever virus damage the host?

It replicates massively in the liver, kidneys, and heart, causing hemorrhaging, shock, jaundice, and severe systemic disease

Is the damage due to toxicity, invasiveness, or both?

Damage is primarily due to intracellular viral replication (invasiveness at the cellular level), leading to organ degeneration and hemorrhaging.

General virulence factors (generally speaking)?

Intracellular replication, adhesins that help the virus attach to host cells

What virulence factors are associated with this plague?

Intracellular replication cycle in the liver and adhesins

How is yellow fever transmitted?

Transmitted by the bite of an infected Aedes aegypti mosquito

Jungle monkeys act as a reservoir, and mosquitoes transmit it to humans.

What is the mode of infection?

You catch yellow fever by being bitten by an Aedes aegypti mosquito carrying the virus.

What is the source of pathogen?

The virus resides in Aedes aegypti mosquitoes and jungle monkeys (reservoir). The mosquito transmits it to humans.

Is yellow fever passed by human-to-human contact?

No. Transmission requires an infected mosquito.

What are the symptoms of yellow fever?

Stage 1 (early): slight fever, headache, myalgia, vomiting (3-4 days)

Stage 2 (remission): symptoms temporarily resolve)

Stage 3 (severe in 15%): delirium, seizures, coma, degeneration of liver/kidneys/heart, massive hemorrhaging, high fever, nausea, nosebleed, shock, “black vomit”, and jaundice

Are there any commonalities?

Fever, malaise-type symptoms (headache, aches, nausea), and progressive systemic involvement, similar to other systemic viral infections.

What is the progression of the disease?

1. Mosquito bite introduces virus

2. incubation 3-6 days

3. Stage 1: slight fever, headache, myalgia, vomiting (3-4 days)

4. Stage 2: remission, temporary disappearance of symptoms

5. Stage 3: (15%) delirium, seizures, coma, hemorrhaging, organ degeneration, jaundice, shock

6. Severe cases have 20% mortality