The 4 major hemorhagic viruses

Question 1

All VHF viruses are what kind of viruses?

Answer 1

RNA

Question 2

Name the 4 VHF viruses

Answer 2

Arenaviridae, bunyaviridae, Floriviridae, flavivirida

Arena, bunya, flora, flavi

Question 3

Two flaviviruses

Answer 3

Dengue fever and yellow fever

Question 4

What is the structure of flavi?

Answer 4

enveloped +RNA

Question 5

Describe the flavivirus replication process

Answer 5

• Enters via pH dependent receptor mediated endocytosis
• +RNA genome is translated into one polyprotein which is cleaved to give viral polymerase and structural proteins
• Virions bud into intracellular organelles and are transported to surfact via exocytic pathway

Question 6

What happens in a flavivirus infection?

Answer 6

Mosquito bites, virus initially replicates at the site.
Virus seeds itself in secondary target tissue, Macrophage, spleen, lymph….This is when you get flu-like symptoms
Secondary viremia starts, if no immune response you get yellow fever hepatitis….Dengue virus infects endothelial cells and leads to hemorrhagic feartures.

Question 7

Dengue Fever

Answer 7

Mostly aquired abroad…four serotypes (1,2,3,4)

Question 8

Infection with one serotype does not provide protection to the others.

Answer 8

True

Question 9

If you have been infected with dengue once, it is more serious the second time.

Answer 9

True

Question 10

Dengue symptoms

Answer 10

Flu like, rash, treatement with fluids and tylenol

Question 11

What is the more severe form of Dengue fever

Answer 11

Dengue hemorhagic fever…characterized by severe thrombocytopenia, leads to intense capillary leakage

Question 12

Is it important to get a lab confirmation for Dengue fever?

Answer 12

Yes…it can appear very similar to other illnesses like malaria.

Question 13

How do you test for Dengue

Answer 13

Look for 4 fold raise in antibody titer in IgG or IgM.

Question 14

How do you treat Dengue hemorrhagic fever

Answer 14

Platelett transfusion and fluid

Question 15

What does yellow fever presesnt as?

Answer 15

flu-like, progresses to hemorhagic fever, jaundive (hence the yellow), black vomit

Question 16

Is there a vaccine for yelow fever

Answer 16

Yeah, live attenuated

Question 17

Hos is yellow fever spread?

Answer 17

Usually in the jungle through mosquitoes and primates. Humans become infected and take it back to urban environments where it is then spread through mosquitos.

Question 18

How does YF progress

Answer 18

Most cases are asymptomatic. For those that cause sickness, the initial infectionis flu like. Then comes a brief remission. Then comes the pain….fever, jaundice, bleeding, shock

Question 19

Treatment is YF

Answer 19

Supportive, fluids, vasoactive meds, etc…

Question 20

Bunyavirus structure

Answer 20

Enveloped, segmented, single strand, -RNA

Question 21

Three kinds of bunya

Answer 21

Rift valley fever, crimean congo,Hanta

Question 22

How is rift valley fever transmitted

Answer 22

Mosquitoes

Question 23

Crimean congo

Answer 23

ticks

Question 24

Hanta

Answer 24

rodents

Question 25

Buntavirus replication cycle

Answer 25

Endocytosed, viral polymerase carried within virion transcribes +RNA (this must be first! This RNA is translated by host proteins

Question 26

Rift valley fever hihglights

Answer 26

causes abortion in livestock potential bioterrorism agent majorioty of human infection from blood or organs of dead animals

Question 27

RVFV in humans

Answer 27

Flu like at first, only progresses in 2% of pts,

Question 28

WHat organ is most affected by RVFV

Answer 28

Liver...also a nerological component like meningitis, fever, encephalitis, possible blindness

Question 29

Crimean congo highlights

Answer 29

headache, limb pain, bleeding from orifices

Question 30

Hantavirus highlights

Answer 30

Spread through rodents excretion, 1-2 weeks after exposure, fever, hemorhage, renal failure, 15% mortality rate

Question 31

Arenavirus

Answer 31

enveloped, segmented ambiscence, aerosol spread, bioterrorism

Question 32

arenavirus vaccine

Answer 32

No

Question 33

Filovirus structure

Answer 33

envelope, non seg, -RNA

Question 34

Two filoviruses?

Answer 34

Marburg and EBOLA

Question 35

Filoviruses highlights

Answer 35

Very high fatality, spread through direct contact with blood and body fluid

Question 36

Filo replication

Answer 36

binds a protein, Membrane fusion initiated by Cathepsin and low pH, brings in a viral RNA polymerase to make +RNA,

Question 37

Ebola is macrophage and monocyte trophic

Answer 37

True

Question 38

Ebola presentation

Answer 38

Bleeding from skin and orrifices, huge spleen, lesions on liver

Question 39

Treatment of Ebola

Answer 39

You're fucked...take fluids and pray