Yellow Fever

Question 1

Yellow fever is transmitted via mosquitos. Is this a virus of bacteria?

Answer 1

• virus

This is an Arbovirus as it is transmitted by mosquitos

Part of the same family as Zika, Dengue fever and Chikungunya

Question 2

Which 2 parts of the world is yellow fever most common in?

1 - South East Asia
2 - South America
3 - North West Asia
4 - Africa

Answer 2

2 - South America
4 - Africa

Endemic in these regions (meaning it has a high incidence here)

Question 3

What is the incubation period of yellow fever?

1 - <24h
2 - 3-6 days
3 - <11 days
4 - >21 days

Answer 3

2 - 3-6 days

Question 4

Is yellow fever virus a intracellular or extracellular virus?

Answer 4

• Intracellular
  The virus is single stranded mRNA, so it needs the host cells to replicate

Intracellular = low neutrophils
Pathogens MUST enter cells to replicate

Extracellular = high neutrophils
Pathogens do NOT need to enter cells to replicate

If pathogen is inside the cell the neutrophils cannot target it, and therefore neutrophils are low = low neutrophils
Pathogens MUST enter cells to replicate

Extracellular = high neutrophils
Pathogens do NOT need to enter cells to replicate

If pathogen is inside the cell the neutrophils cannot target it, and therefore neutrophils are low

Question 5

Oncer bitten by a mosquito, which cell does the yellow virus typically target?

1 - B cells
2 - T cells
3 - neutrophils
4 - dendritic cells

Answer 5

4 - dendritic cells

Present in skin, so easy to access once bitten

Question 6

Once infected with the yellow fever virus, all of the following organs are targeted, but typically which is the 1st organ targeted?

1 - kidneys
2 - heart
3 - liver
4 - stomach

Answer 6

3 - liver
Causes jaundice and hepatitis

Kidneys
- causes tubular damage and renal failure

Heart
- cardiocyte damage and arrhythmias

Stomach
- mucosal damage and bleeding

Question 7

Are all patients with yellow fever symptomatic?

Answer 7

• no

Most are asymptomatic, but if symptoms do present, its after 3-5 days

Question 8

The initial symptoms of yellow fever are due to the infection in the blood. Which of the following is NOT one of the initial symptoms?

1 - nausea, vomiting and severe headache
2 - fever with chills
3 - hepatitis
4 - back pain
5 - fatigue

Answer 8

3 - hepatitis

In most patients these initial symptoms improve over 3-4 days and then disappear

Question 9

Like Dengue fever, does yellow fever affect platelet number?

Answer 9

• yes

Can cause thrombocytopenia

Question 10

If the patients initial symptoms of yellow fever begin to improve, 3-4 days after onset, do they always get better?

Answer 10

• no

Sometimes can get worse, called remission period, which is due to infection spreading to organs

Question 11

Based on the organs affected, which of the following is NOT likely to occur in patients with established yellow fever?

1 - coffee ground vomit
2 - photophobia
3 - reduced urine output
4 - jaundice and upper abdo pain

Answer 11

2 - photophobia

Icterus will be present, but not this

Question 12

How is yellow fever typically diagnosed?

1 - rt-PCR
2 - culture
3 - clinical diagnosis
4 - ELISA

Answer 12

3 - clinical diagnosis
History and symptoms

Real time PCR can be performed to confirm the diagnosis

Question 13

What is the treatment of choice in yellow fever?

1 - oral fluids and paracetamol
2 - IV fluid and paracetamol
3 - Antivirals
4 - Steroids

Answer 13

1 - oral fluids and paracetamol

IV can be given if in hospital

Question 14

Are NSAIDs ok to be given to patients with yellow fever?

Answer 14

• no

Yellow fever causes tubular damage, renal failure, and gastric bleeding, all of which NSAIDs would amplify