Arbo 2 Flashcards Preview

Virology > Arbo 2 > Flashcards

Flashcards in Arbo 2 Deck (75):
1

4 hallmarks of WNV

Menigitis

Encephalitis

Mengingoencephalitis

PolioMyelitis

2

Three conditions of WN encephalitis?

Asymptomatic infection

West Nile Fever

Neuroinvasive disease

3

About __% of West Nile infections are asymptomatic

80%

4

About __% of patients develop West Nile Fever, from which most people ____

20%, Recover

5

West Nile Fever lasts about ______ days

3-6

6

Hallmark for CNS disease from West Nile VIrus? How many patients progress to this stage?

Erythematous maculopapular or morbilliform rash

 

Less than 1%

7

WNV infects ____ cells

Langerhans Dendritic

8

WNV vauses primary viremia after migrating to ______

lymph nodes

9

Does WNV cause 2' viremia?

Yes

After dissemination to RE system

10

_____ limits WNV dissemination to the CNS

Patients that progess past this point may have less robust ___ response

Antibodies

IgM

11

_____ results in WNV clearance from infected neurons

CD8 T cell response

12

WNV major vector and intermediate host

Mosquito Vector

Bird intermediate host

13

Other than mosquito to man, what are other ways we can and can NOT get WNV?

No: Man to man or animal to man

Yes: Live or dead bird, consumption of infected bird

Other: Blood transfusions, organ transplants, lab exposure, or from Mom > Baby

14

WNV vaccines are approved for ___

Equine use

15

Dengue Serotypes

1-4

16

Increased _______ helps in spreading Dengue

air travel

17

Explain the Dengue infection in terms of serotypes and immunity

If infected with one, it does not provide protection against the other three

It actually increases the severity of subsequent Dengue infections

18

Dengue presents ___ days after bite

3-15

19

Does Dengue cause a fever?

Yes - saddleback fever up to 106 degrees

20

Most people recover from Dengue within _____

one week

21

Two Dengue Clinical presentations (syndromes)

  1. Dengue Hemorrhagic Fever (DHF)
  2. Dengue Shock Syndrome (DSS)

22

Most DHF patients are how old?

under 15 years

23

Characteristic manifestations of DHF

  • Plasma leakage
  • bleeding from trauma sites
  • GI bleed
  • Hematuria
  • Seizures and CNS symptoms

24

What is DSS?

Dengue shock syndrome - it is untreated DHF that has progressed to circulatory failure

25

Dengue targets what cells?

Langerhans (dendritic) cells

26

Dengue pathogenesis (6 steps)

  1. infects langerhans
  2. APC to T cells
  3. Enter Monocyte/endothelial cells, attacked by CD4/CD8 and cytokines
  4. activates immune system
  5. increases vascular permeability (plasma leaks)
  6. Hemoconcentration and hypovolemic shock occur

27

Dengue is enhanced in an __________ fashion

antibody-dependent

 

*they aid virus in getting into cells

28

sEach DENV (Dengue) serotype has the ability to cause _______ infections

ALL TYPES

(asymptomatic,  DF,  DHF,  DSS)

29

______ are most affected by Dengue

Children

30

Dengue in US occurs primarily in ___________________

travelers from endemic areas

31

Dengue mainly spread by ______ 

Aedes aegypti mosquito

32

Can dengue be transmitted from human to human?

YES

33

Primate cycle of transmission is called ________

Sylvatic / Enzoonotic

34

Dengue control and treatment

No treatment (supportive therapy only)

Immunization is hard because of SEROTYPES

35

Yellow Fever stages

Initial symptoms

Toxic Stage

Late Stages

36

YF initial symptoms

abrupt flu like symtoms (with fever)

37

YF toxic phase develops after...

initial remission of symptoms and fever

38

YF toxic phase hemorragic manifestations are caused by...

hepatic induced coagulopathy.

 

causes hematemesis, epistaxis, gingival bleeding and petechial hemorrhages

39

YF toxic phase - systemic manifestations?

jaundice and albuminuria

40

Late stage YF manifestations

  • Hypotension, shock
  • Metabolic Acidosis
  • Acute Tubular Necrosis
  • Heart dysfunction and arrhythmia

41

What distinguishes the CNS symptoms of the late stages of YF?

Confusion 

seizure 

Coma

42

________ are complications in patients who survive late-stage YF

Secondary bacterial infections

43

YF replicates initially at ___________

local lymph nodes

44

Where does YF spread to once initial infection occurs?

First to other lymph tissue, spleen and bone marrow

 

Then to liver, lungs, and adrenals

45

Most important organ affected by YF?

Liver

46

______ form in the liver during YF

Councilman bodies 

 

(apoptotic hepatocytes)

47

2nd most affected organ by YF?

What systemic changes result from this?

Kidney 

Albuminuria and renal insufficiency

48

YF hemorrhage is from reduced _________ and can result in _________

reduced clotting factor production by liver

Results in: Hematemesis, thrombocytopenia, and platelet dysfunction

49

The terminal event of YF is _____.

 

What two things can this be attributed to?

shock

 

from direct parenchymal damage and systemic inflammatory response

50

Almost everyone that enters the toxic stage of YF...

progresses to the late (third) stage

51

Yellow Fever Vaccine properties/dosage

Vaccine = Live attenuated (Stamaril)

Single dose gives 100% immunity for 10 years

single SubQ injection

52

The arboviral togaviridae are...

Alphaviruses

EEEV, WEEV, VEEV

53

Alphavirus genome structure

ss+RNA

Enveloped

Icosahedral capsid

54

Alphavirus has ______ for attachment

glycoprotein spikes

but NO receptor is known!!

55

Alphavirus replication occurs in _____

cytoplasm

56

Alphavirus parental ___ RNA strand encodes ______.

The resulting molecule is re-coded into _______.

This RNA is made into ___   and  _____.

This results in production of ______.

parental +RNA makes Nonstructural proteins in 5' end

Molecule recoded into (-) RNA

Made into progeny +RNA is made into +mRNA

This results in production of progeny virus

57

EEE has a ____ period first

Prodromal

58

EEE progresses more rapidly to _____ and ______

CNS and death

59

CNS symptoms of EEE

General (headavhe, nausea, confusion)

Focal defecits (sensory/motor loss, seizures, stiff neck, cranial nerve palsies, photophobia)

60

Pathogenesis of EEE

mosquito injects virus subQ

Non-CNS replication during prodrome

2' viremia = CNS invasion

immune cells enter brain and damage

Gross inspection = edema, vascular congestion, hemorrhage, ENCEPHALOMALACIA

61

Equine Encephalitis' resevoirs

Mosquitos, Birds (WEE and EEE)

Rodents (VEE)

 

 

*also amphibians and reptiles

62

Incidence of EEE

only 5% of EEEV results in EEE

63

What happens immunologically after EEEV infection?

lifelong immunity

64

EEEV most common in ____ United States

Southeastern

65

WEE incubation time

Short (1-4 days)

66

Initial WEE symptoms are...

flu-like

subclinical in many people

67

WEE Neuro symptoms indicate

poorer prognosis

Symptoms similar to EEE (Focal defecits, seizures, neck stiffness and photophobia)

68

________ is rarer in WEE than EEE

cranial nerve palsy

69

WEE is most common during

Summer months (April - September)

70

VEE presentation can be ___, ___, or ___

 

(with symptoms)

MILD (flulike)

MODERATE (+ photophobia back pain, fever)

SEVERE (acute high fever, severe myalgia and back pain, photophobia, prostration, confusion)

71

In Alphavirus, ____ and ____ are dead end hosts

humans and horses

72

Alphavirus can be transferred to mosquitos from ____

Birds

73

Alphavirus control is based on _______

disease surveillance

74

Vaccine for Alphavirus? Who is it used for?

Inactivated vaccine

used for lab workers

75

What vaccine has been used for Alphavirus in horses?

live-attenuated VEE vaccine

 

*similar one used for lab workers