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Flashcards in RNA viruses Deck (100):
1

RNA virus are divided to

1. helical nucleocapsid
2. icosahedral nucleocapsid

2

RNA virus - helical nucleocapsid - diagram

helical nucleocapsid --> enveloped:
1. SS- segmented:
a. Bunyaviridae)
b. Arenoviridae (Arenovirus)
c. Orthomycoviridae (Influenza A,B,C)
2. SS+ nonsegmented
a. Coronoviridae --> Coronovirus
3. SS- nonsegmented
a. Filoviridae (filovirus)
b. Rhbdoviridae (lyssavirus)
c. Paramyxoviridae (Parainfluenza, RSV, Measles, Mumps)

3

RNA virus - icosahedral nucleocapsid - diagram

1. Nonenveloped
A. SS+ non-segmented
- Picornaviridae --> a. Rhinovirus B. enterovirus (Poliovirus, Hepatitis A virus, coxsackievirus, echovirus)
- Caliciviridae --> Clicivirus (Norovirus, Hepatitis E)
B. DS segmented --> Reoviridae (Rotavirus, Coltivirus)
2. Enveloped
A. SS+ diploid --> Retrovirus (HIV, HTLV-1, HTLV-2)
B. SS+ non-segmented
- Flaviviridae (Flavivirus)
- Togaviridae (rubella, Eastern equine encephalitis, Western equine encephalitis)
C. SS- circular --> Deltavirus (NOT EXACTLY icosahedral nucleocapsid)

4

which RNA virus helical nucleocapsid are enveloped

all

5

RNA SS+ non segmented helical nucleocapsid virus

coronovirus

6

coronovirus - characteristics

RNA virus, helical nucleocapsid, enveloped, SS+ non-segmented

7

coronovirus causes

1. common cold
2. Severe acute respiratory syndrome (SARS)
3. Middle East Respiratory Syndrome (MERS)

8

RNA virus, helical nucleocapsid enveloped, SS- segmented

a. Bunyaviridae
b. Arenoviridae (Arenovirus)
c. Orthomycoviridae (Influenza A,B,C)

9

Orthomycoviridae - characteristic and virus

RNA virus, helical nucleocapsid enveloped, SS- segmented (8)
Influenza A,B,C

10

Influenza viruseses - family and characteristics

Orthomycoviridae
RNA virus, helical nucleocapsid enveloped, SS- segmented

11

Influenza viruses - specific antigens and actions

1. hemagglutinin --> promotes viral entry
2. neuraminidase --> promotes progeny virion release

12

Influenza viruses infection increases the risk for

fatal bacterial superinfection (Most commonly S. aureus, S. pneumonia, H. influenzae)

13

Influenza viruses - vaccines - characteristics, rout of administration, structures etc

Reformulated vaccine ("the flu shot") contains viral stains most likely to appear during the flu season
- Killed viral is most frequently used --> (injected)
- Live attenuated vaccine contains temperature sensitive mutant that replicates in the nose but not in the lung --> intranasally

14

Influenza viruses - types of vaccines (and route of administration) (Most freq use?)

killed --> injected (MC)
Live attenuated --> intranasally

15

Influenza viruses - special characteristic of live cycle

Rapid genetic changes

16

causes of influenza virus Rapid genetic changes - ways

1. Genetic shift/antigenic shift
2. Genetic drift/antigenic drift

17

genetic shift/antigenic shift mechanism

Reassortemnt of viral genome segments

18

Genetic drift/antigenic drift mechanism and example

Minor changes based on random mutation in hemagglutinin or neuraminidase

19

genetic shift/antigenic shift example

segments of human flu A virus reasort with swine flu A virus

20

Genetic drift/antigenic drift vs genetic shift/antigenic shift according to resutls

- genetic shift/antigenic shift causes pandemics
- genetic drift/antigenic drift causes epidemics

21

Arenoviruses characteristics and viruses

RNA virus, helical nucleocapsid enveloped, SS- segmented (2)
1. Lassa virus
2. LCMV - lymphocytic choriomeningitis virus

22

Lassa virus causes

Lassa fever ecephalitis (a form of hemorrhagic fever)

23

Lassa virus transmission

- spread by rodents (contaminated food or water by rodent urine
- person to person via bodily fluids

24

Bunyaviridae - characteristics and viruses

RNA virus, helical nucleocapsid enveloped, SS- segmented (3)
1. california encephalitis virus
2. Rift valley river virus
3. Crimean Congo hemorrhagic fever virus
4. Hantavirus

25

Hantavirus - characteristics clinical manifestation

hemorrhagic fever, pneumonia

26

RNA virus, helical nucleocapsid, enveloped SS- nonsegmented

a. Filoviridae (filovirus)
b. Rhbdoviridae (lyssavirus)
c. Paramyxoviridae (Parainfluenza, RSV, Measles, Mumps)

27

Filoviridae (filovirus) characteristics and viruses and their resevoir

RNA virus, helical nucleocapsid, enveloped SS- nonsegmented
1. Marburg virus --> monkey reservoir
2. Embola virus --> unknown, maybe bats

28

Embola virus - mechanism

targets epithelial cells, phagocytes, hepatocytes --> incubation period of up to 21 days --> symptoms

29

Embola virus - course

abrupt onset of flu-like symptoms, diarrhea/vomiting, high fever myalgia --> DIC, diffuse hemrrhage, shock --> high mortality rate

30

Filoviridae (filovirus) viruses and their outcome

1. Marburg virus
2. Embola virus
HIGH MORTALITY

31

Embola virus - treatment

no definitive treatment, supportive care
Strict isolation of infected individuals and barrier practices for health care workers are key to preventing transmission

32

Embola virus - transmission

requires direct contact with bodily fluids or fomites (including dead bodies)

33

Embola virus - nosocomial infections

HIGH INCIDENCE

34

Embola virus - diagnosis

RT-PCR within 48hr of symptoms onset

35

lyssavirus - characteristics

RNA virus, helical nucleocapsid, enveloped SS- nonsegmented - Rhbdoviridae

36

Rabies virus - appearance

Bullet shaped virus (electrical microscope)
Negri bodies (commonly found in Purkinje cells of cerebellum and hippocampal neurons)

37

Rabies virus - negri bodies commonly found in

Purkinje cells of cerebellum and hippocampal neurons

38

Rabies virus - source in US

More commonly from bat, raccoon and skunk than from dog bites in the US
- aerosol also possible

39

Rabies virus - progression of disease

Long incubation period (weeks to months) --> fever, malaie, agitation, photophobia, hydrophobia, hypersalivation --> paralysis and coma --> death

40

Rabies virus - pathophysiology

Travels to the CNS by migrating in a retrograde fashion up nerve axons after binding to nicotinic ACH receptors

41

Rabies virus - Post-exposure prophylaxis

1. wound cleaning
2. imunization with killed vaccine
3. rabies immunoglobulin
(PASSIVE ACTIVE IMMUNITY)

42

Rabies virus - type of vaccine

killed

43

Paramyxoviridae - characteristics and virus

RNA virus, helical nucleocapsid, enveloped SS- nonsegmented
1. Parainfluenza
2. RSV
3. Measles
4. Mumps

44

Paramyxoviridae causes disease in

children and infants

45

all Paramyxoviridae contain (stractural characteristic)

surface F (fusion) protein, which causes respiratory epithelial cells to fuse and form multi-nucleated cells

46

monoclonal antibody against F protein

Palivizumab

47

Palivizumab mechanism of action and clinical use

- monoclonal antibody against F protein
- prevent pneumonia caused by RSV infection in premature infants

48

RSV causes

respiratory tract infection (bronchiolitis, pneumonia) in infants

49

Mumps virus infection - symptoms

1. parotitis
2. orchitis
3. Aseptic meningitis
4. Pancreatisis

50

Mumps virus infection - complication

can cause sterility, especially after puberty

51

Parainfulenza causes

Croup (acute laryngotracheobronhitis)

52

Croup (acute laryngotracheobronhitis) is result in .... (and caused by)

is caused by Parainfulenza
results in "seal-like" baking cough and inspiratory stridor
severe croup can result in PULSUS PRADOXUS 2ry to upper airway obstruction

53

Croup (acute laryngotracheobronhitis) - image

Narrowing of upper trachea and subglottis lead to characteristic steeple sign on X-RAY

54

Croup (acute laryngotracheobronhitis) - sign on x-ray (only the name)

steeple sign

55

Measles virus causes (and in greek)

measles (rubeola) (ιλαρά)

56

measles (rubeola) usual presentation

prodromal fever with cough, fever and conductivities, then eventually Koplik spots, followed (1-2days) by maculopapular rash that starts on at the head/neck and spreads downward
- Lymphadenitis with Warthin-Finkeldey giant cells (fused lymphocytes) in a background of paracortical hyperplasia

57

Koplik spots?? They are associated with?

bright red spots with blue-white center on buccal mucosa that precede the measles rash by 1-2 days
measles (rubeola)

58

3 C's of measels

Cough
Coryza
Conjunctivitis

59

measles (rubeola) - possible sequelae

1. Subacute sclerosing panencephalitis (SSPE) - years later
2. enecephalitis (1:2000)
3. giant cell pneumonia (rarely, in imminosuppressed)

60

measles (rubeola) - treatment

Vitamin A supplementation can reduce measles mortality and morbidity in malnourished or vitamin-deficient children

61

Picornaviridae - characteristics and viruses

RNA virus - icosahedral nucleocapsid - nonenveloped - SS+ non-segmented - Picornaviridae:
1. Rhinovirus
2. Enterovirus (Poliovirus, Hepatitis A virus, coxsackievirus, echovirus)

62

Picornaviridae causes (each virus)

1. Rhinovirus --> common cold
2. Poliovirus --> polio, aseptic meningitis
3. Echovirus --> aseptic meningitis
4. HAV --> acute viral hepatitis
5. Coxsackievirus --> aseptic meningitis, herpangina (mounth blisters, fever), hand - foot and mount disease, myocarditis, pericarditis

63

Coxsackievirus causes

aseptic meningitis, herpangina (mounth blisters, fever), hand - foot and mount disease, myocarditis, pericarditis

64

Picornaviridae - transmission

all fecal-oral except rhinovirus

65

Picornaviridae - mechanism of infection

RNA is translated into 1 large polypeptide that is cleaved by proteases into functional viral protein

66

caliciviridae - characteristics and viruses

RNA virus - icosahedral nucleocapsid - Nonenveloped - SS+ non-segmented --> Caliciviridae --> Calicivirus:
1. Norovirus
2. HEV (now it is not a calicivirus)

67

Norovirus causes

viral gastroenteritides

68

Rhinovirus - family / causes / how many types

picornavirus --> common cold
more that a hundred types

69

Rhinovirus - special characteristics vs other picornaviruses

Rhinoviridae is acid labile - not destroyed by stomach acid --> not infect GI tract
- no fecal oral transmission

70

Reoviridae - characteristics and viruses

RNA virus - icosahedral nucleocapsid (DOUBLE) - nonenveloped - DS segmented - reoviridae:
1. Rotavirus
2. Coltivirus

71

Reoviridae - special characteristic of structure

icosahedral nucleocapsid (DOUBLE)

72

viruses with double icosahedral nucleocapsid

Reoviridae

73

Rotavirus causes

- MCC of fatal diarrhea in children
- the most important global cause of infantile gastroenteritis
- Major cause of diarrhea in USA during winter especially in day care centers, kindergartens

74

Coltivirus causes

Corolando tick fever

75

rotavirus - mechanism of action

villous destruction with atrophy leads todecreased absorption of Na+ and loss of K+

76

Rotavirus - major cause of diarrhea in USA during ...(and places)

winter especially in day care centers, kindergartens

77

Rotavirus - recommendation

CDC recommends routine vaccination of all infants

78

rotavirus vaccine type

live attenuated

79

Poliovirus - vaccine (type and rout)

1. Salk --> killed (inactivated poliovirus vaccine (IPV)) --> injection
2. Sabin --> live attenuated vaccines (oral poliovirus vaccine (OPV)) --> oral

80

Delta virus - characteristics and viruses

SS - circular enveloped - (NOT EXACTLY icosahedral nucleocapsid - Delta virus:
HDV

81

HDV functional special characteristics

HDV is a "defective" virus that requires the presence of HBV to replicate

82

Delta virus - nucleocapsid

uncertain - NOT EXACTLY icosahedral nucleocapsid

83

Retroviruses - characteristics and viruses

RNA virus - icosahedral nucleocapsid - Enveloped
SS+ diploid --> Retrovirus
1. HIV
2. HTLV-1
3. HTLV-2

84

HTLV causes

T-cell leukemia

85

Retroviruses - nucleocapsid

HTLV --> icosahedral
HIV --> NOT EXACTLY icosahedral --> complex and conical

86

flaviviridae - characteristics and viruses

RNA virus - icosahedral nucleocapsid - Enveloped - SS+ non-segmented --> Flaviviruses:
1. HCV
2. Yellow fever
3. Denque fever
4. St Louis encephalitis fever
5. West Nile fever

87

Yellow fever - transmission / reservoir

Aedes mosquitoes (monkey or human reservoir)

88

Yellow fever symptoms

high fever
black vomitus
jaundice

89

Yellow fever biopsy

Councilman bodies (eosinophilic apoptotic globules) on liver biopsy

90

Flaviviruses - name

Flavi = yellow, jaundice

91

Yellow fever - vaccine - type

live attenuated

92

Togaviridae - characteristics and virus

RNA virus - icosahedral nucleocapsid - Enveloped - SS+ non-segmented --> togaviruses
1. rubella
2. Eastern equine encephalitis
3. Western equine encephalitis

93

Rubella virus causes (and aka)

rubella (German (3-day) measles)

94

rubella - symptoms

MILD disease in children but SERIOUS congenital disease
1. Fever
2. postauricular and other lymphadenopathy
3. arthralgias
4. fine rash (confluent macules that starts on the face and spread centrifugically to involve the trank and extremities

95

congenital rubella causes

1. Blueberry muffin appearance (rash)
2. classic triad a. PDA (or pulmonary artery hypoplasia b. cataracts c. deafness

96

congenital rubella - Blueberry muffin appearance?

indicative of dermal extramedullary hematopoiesis

97

(-) stranded viruses - mechanism

must transcribe (-) strand to (+). Virion brings its own RNA-depended RNA polymerase

98

arbovirus means

arthropod borne (mosquitos, ticks)

99

arbovirus - viruses?

1. all Bunyaviruses except hanta
2. All togaviruses except rubella
3. All flaviviruses except HCV
4. Coltivirus

100

Reovirus, orthomyxovirus, arenavirus, bunyavirus - number of segments

Reovirus - 10-12
orthomyxovirus - 8
arenavirus - 2
bunyavirus - 3