L83

Question 1

Flavi viruses: RNA or DNA?
Capsid spherical or icosohedral?
Released diseases

Answer 1

\+ssRNA - "..flavored Coronas..."
Icosohedral capsid
4 diseases
1. Hep C
2. West Nile
3. Dengue fever + St. Louis
4. Yellow fever

Question 2

Toga viruses: RNA or DNA?
Capsid spherical or icosohedral?
Released diseases

Answer 2

+ssRNA “I went to a retro toga party…”
Icosohedral capsid
Disease = chikungunya

Question 3

Bunya viruses: RNA or DNA?
Capsid: helical, spherical, icosohedral?
Released diseases

Answer 3

-ssRNA “always Bring…”
Helical capsid
Hantavirus

Question 4

Arena viruses: RNA or DNA?

Released diseases

Answer 4

-ssRNA “Always bring…”

Lassa

Question 5

Filo viruses: RNA or DNA

Related disease

Answer 5

-ssRNA “always bring pol or Fail rep”

Ebola

Question 6

What is common to all the zoonotic diseases?

Answer 6

All enveloped in lipid membrane - will break down in detergent
Aka main leaving mechanism is BUDDING

Question 7

How do you diagnose all the zoonotic diseases?

Answer 7

Serology & PCR

Clinical picture isn’t enough b/c non-specific symptoms

Question 8

What is the common disease category for all of these viruses? What must be part of treating any pt with one of these diseases?

Answer 8

Viral hemorrhagic fevers

Pt isolation required!

Question 9

Brazil 
Ab pain + fever
Intractable vomiting
Abnormal coag, renal + liver failure 
5 days after symptoms - died: shock, seizures, excessive bleeding at line sites
WHAT IS THE DISEASE?

Answer 9

Yellow fever

Question 10

What virus causes yellow fever?

Answer 10

Flavi

Question 11

What is the main organ target in yellow fever?

Answer 11

Liver –> hepatitis

Question 12

How is yellow fever transmitted?

Answer 12

Mosquito

1. Urban - man to mosquito over and over
2. Jungle

Question 13

You’re worried about travelers from WHERE with yellow fever?

Answer 13

Brazil aka Amazon

Middle Africa around the equator

Question 14

What are the 1ary, 2ary, and terminal symptoms of YF?

Answer 14

1 - fever + ab pain
2 - liver is failing = abnormal coag + black vomit
+ renal failure
Terminal - excessive bleeding, general shock

Question 15

Diagnose YF

Answer 15

PCR for RNA

Question 16

1: fever + headache + chills - bacteruria & hematuria
2: retro-orbital pain, worse when move eyes
↓WBC ANDDDD platelets!!
3: petechiae on LE
WHAT IS THE DISEASE?

Answer 16

Dengue

Question 17

What virus causes Dengue Fever?

Answer 17

Flavi

Question 18

You’re worried about travelers from WHERE with Dengue Fever?

Answer 18

Caribbean - Key West
South America
Asia

Question 19

What is Dengue Fever vs Dengue shock syndrome?

Answer 19

1st infection = DFever - mild, acute infection

2nd infection w/ different serotype (no Ab protect) = DSS, hemorrhagic fever & shock

Question 20

Describe Dengue Fever pathogenesis

Answer 20

Mosquito bite
Infect DCs & monocytes
–> LN –> 1ary viremia
Develop immune response here - specific to the infecting serotype (no lasting immunity to other serotypes)

Question 21

Describe 2nd infection of DF

Answer 21

Same serotype - Ab protection
Different serotype - DSS
- Abs try to bind new serotype –> ineffective
- Now these Abs are a “new binding site” for uptake of active virus into APCs
- Virus infects these APCs –> accelerated infection –> worse outcomes
Net: hemorrhage syndrome & shock

Question 22

Does DF always present with petechiae?

Answer 22

No - can if there is hemorrhage in the 1ary infection

Question 23

Acute fever for 1-3 wks
Followed by severe, debilitating joint pain lasting for months/years
WHAT IS THE DISEASE?

Answer 23

Chikungunya virus

Question 24

Since Degnue and chikungunya viruses often co-circulate and present similar clinical pictures, how do you differentiate?

Answer 24

Dengue - thrombocytopenia & can have shock

Not in chikungunya

Question 25

What viral family is chik in?

Answer 25

Toga

Question 26

Describe chik pathogenesis

Answer 26

Mosquito bite
Local replication of virus at bite site –> LN
Moves to muscles and joints
Virus persists in muscle cells and macrophages for chronic infection
Immune system will clear infection - just a question of how long

Question 27

What is the immune response for the acute phase vs chronic phase of chik?

Answer 27

Acute - Th1 response

Chronic - Th2 response

Question 28

What type of immunity is the primary mediator of chik?

Answer 28

Ab

Question 29

What viral family is hanta virus in?

Answer 29

Bunya

Question 30

Hanta transmission

Answer 30

Rodents - deer mouse
- fecal-RESP through their droppings
“Sweeping out cabin with animal droppings”

Question 31

What organ system symptoms are hallmarks of hanta?

Answer 31

Hanta pulmonary syndrome - SOB, respiratory distress

Question 32

What virus family is lassa in? What is unique about the genome?

Answer 32

Arena

Lassa has 2 genetic RNA segments - each has specific polarity

Question 33

Where are you worried about travelers and lassa fever?

Answer 33

West Africa

Question 34

Lassa transmission

Answer 34

rats

Question 35

Symptoms and disease of lassa fever

Answer 35

= Viral hemorrhagic fever

Fever/chills, sore throat, back pain

Question 36

Who are you worried about dying from lassa fever?

Answer 36

Pregnant women (3rd trimester) & fetus

Question 37

Treat lassa fever

Answer 37

Ribavirin

Question 38

Describe how liver enzymes and platelets change during Ebola?

Answer 38

Liver enzymes - rise early, go VERY high late

Platelets plummet

Question 39

Which of these infections can be transmitted back to the vector after a person has been infected?

Answer 39

Mosquito borne ones:

• YF
• Dengue
• Chik

Question 40

In general, can you treat any of these with meds? Vaccinate?

Answer 40

Treat - no, all supportive

Vaccinate - only YF