RNA Virus - Myxovirus Flashcards

1
Q

Myxovirus includes

A

Orthomyxovirus
Paramyxovirus

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2
Q

Members of Orthomyxovirus family

A

Influenza A, B and C

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3
Q

Members of Paramyxovirus family

A

M - Measles
M - Mumps
R - Respiratory Synctial virus
Parainfluenza
Nipah virus

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4
Q

Size and RNA form of Orthomyxovirus and Paramyxovirus

A

Orthomyxovirus - size : 110nm
RNA - Segmented
Paramyxovirus - Size : 150nm
RNA - unsegmented

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5
Q

Symmetry, RNA sense of Orthomyxovirus and Paramyxovirus

A

Both have helical symmetry
Both are enveloped
Both have Negative sense RNA

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6
Q

Types of Influenza viruses

A

Influenza A - 8
Influenza B - 8
Influenza C - 7

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7
Q

Structure seen on Influenza viruses

A

Hemagglutinin (HA)
Neuraminidase (NA)
M1 And M2 Protein

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8
Q

Hemagglutinin shape and attaches to

A

More in number
Triangular in shape
Attachment to Sialyl acid receptor (Resp. Epithelium, RBC)

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9
Q

Neuraminidase Shape and functions
AKA

A

Less in no.
Mushroom shaped
Helps in release of virus
AKA - Receptor destroying enzyme (RDE) or Sialidase

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10
Q

M1 protein function

A

Beneath envelope
Maintains structural integrity

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11
Q

M2 protein Features

A

Ion channel - H+ influx
Aid in uncoating of virus

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12
Q

Pathogenesis of Influenza viruses

A

Attachment of Hemagglutinin on Sialyc acid receptor - internalized by endocytosis - Uncoating (by M2 protein by causing H+ influx) - Then negative sense RNA is converted to Positive RNA sense with help of RNA Dependent RNA Polymerase - release of virus with the help of Neuraminidase

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13
Q

Group specific typing of Influenza viruses

A

1);Influenza virus A - Human and animals, Antigenic shift, Epidemic and Pandemic
2) Influenza virus B - Humans only, No antigenic shift, Seasonal flu
3) Influenza Virus C - Non pathogenic

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14
Q

Difference between antigenic shift and antigenic drift

A

1) Antigenic shift : Sudden change
Antigenic drift : Gradual change
2) Antigenic shifting : Exchange of RNA segments b/w Influenza A (Genetic reasortment)
Antigenic drift : Mutation in H and N
3) Antigenic shift : cause major epidemics and Pandemics
Antigenic drift - doesn’t cause
4) Antigenic shift - Seen in Influenza A
Antigenic drift - seen in Influenza A and B

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15
Q

Currently circulating strains of Influenza viruses

A

Type A/H1N1 : WHO declared in pandemic on 11th June 2009
Type A/H3N2
Type A/H5N1
Type B

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16
Q

Incubation period of Influenza viruses

A

18-72 hours

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17
Q

Clinical features of Influenza

A

Fever, headache
Sore throat
Myalgia
Runny nose is usually absent
Rarely GI Symptoms
Reye Syndrome AKA Jamshedpur fever

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18
Q

Complication and M/C Extrapulmonary symptom of Influence

A

Complication - Pneumonia
M/C extrapulmonary symptoms - Myalgia

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19
Q

Influenza samples are stored in which media

A

VTM (Viral transport media)

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20
Q

Isolation of Influenza is done on

A

Amniotic cavity of embryonated egg
Cell lines (1° Monkey kidney)

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21
Q

Antigen detection test for Influenza

A

Direct immunofluorescence

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22
Q

Antibody detection of Influenza

A

ELISA - 2 sample to be taken with gap of 2 weeks - 4 fold gap increase
Hemagglutination Inhibition test (HAI)

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23
Q

Hemagglutination Inhibition test Procedure

A

1) RBC - No reaction
2) RBC + virus (influenza) - Hemagglutination - Mat/Carpet Formation
3) RBCs + virus + Antibody (pt. Sample) - Antibody combines with Antigen - Hemagglutination Inhibition

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24
Q

Which tests are sensitive and specific for Influenza

A

RT PCR
Real Time PCR

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25
Q

Neuraminidase inhibitors given by oral route

A

Tamiflu/Oseltamivir

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26
Q

Neuraminidase inhibitor given by Inhalation route

A

Zanamivir/Relenza

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27
Q

M2 Inhibitors used for Influenza A

A

Amantadine
Rimantidine

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28
Q

Vaccines used against Influenza

A

Live Nasal spray -
Inactivated vaccine - Given to healthcare professionals, two doses given annually

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29
Q

Live Nasal spray vaccine for Influenza indications and C/I

A

Trivalent vaccine - H1N1, H3N2 and Type B
Indicated - 2-49 years of age
C/I - if low immunity

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30
Q

Paramyxovirus features

A

Single Unsegmented RNA
Hemagglutinin and Neuraminidase on same spike
F Protein (Fusion protein)

31
Q

Paramyxovirus includes

A

Measles
Mumps
Respiratory Synctial virus
Parainfluenza
Nipah virus

32
Q

Measles also known as

A

Rubeola

33
Q

Incubation period Measles, Mumps and Rubella

A

Measles - 10day (Children), 21 days(Adults)
Mumps - 19day
Rubella - 14day

34
Q

Transmission of Measles virus

A

Inhalation of respiratory droplets

35
Q

Period of communicability of Measles

A

4 days before and 4 days after rash

36
Q

Immunity after Measles infection

A

Lifelong because of single serotype

37
Q

Prodromal symptoms of Measles

A

3C
Coryza
Cough
Conjunctivitis
Fever

38
Q

First manifestation of Measles infection

A

Fever (10th day)

39
Q

Pathognomonic signs of Measles virus

A

Koplik spots (12th day)

40
Q

Koplik spots features

A

White spots on erythematous base
Seen near molars 2-3 days after fever

41
Q

When rash appears in Measles and it’s features

A

On 14th day
Maculopapular rash
Begins behind the ears then on face followed by trunk
Fades thereafter in same order
When rash appears, Fever and Koplik spots disappear

42
Q

Complications of Measles

A

1) Sec bacterial infections - Otitis media, Bronchopulmonary pneumonia
2) CNS Manifestations
3) In pregnancy - Intrauterine Death
4) A/w diarrhea, Pneumonia

43
Q

Type of Pneumonia caused due to measles and histological finding

A

Hecht’s Pneumonia AKA Giant cell Pneumonia - Warthin Finkaldey giant cells

44
Q

CNS Complications caused due to Measles

A

1) Post measles encephalitis - Antibody antigen myelin basic protein
2) SSPE (Subacute Sclerosing Panencephalitis) - occurs after 7-13 years - fatal after 1-3 years

45
Q

Cell line recommended by CDC in case of Measles

A

Vero

46
Q

Cytopathic effect seen in Measles infection

A

Warthin Finkaldey giant cells

47
Q

Vaccines strains For Measles and S/E

A

Edmonston-Zegreb strain - used in India
S/E - Mild measles like disease
Toxic Shock Syndrome (contamination of vial with S. Aureus)

48
Q

Commonly affected age group by Mumps virus

A

5-9 years age group

49
Q

Incubation period and Period of communicability of Mumps infection

A

IP - 19 days
Period : 1 week before and 1 week after symptoms

50
Q

Most common clinical features of mumps

A

Inapparent - causes few or no signs or symptoms

51
Q

Most common manifestation of Mumps

A

Bilateral Parotitis - pain increase on citrus juices

52
Q

2nd most common manifestation in Mumps

A

Unilateral orchitis - doesn’t lead to Sterility

53
Q

Other clinical features of Mumps

A

Aseptic meningitis
Oophoritis in females
Pancreatitis

54
Q

Mumps virus multiply in which organ

A

Multiply in lungs - spill in blood -Organs

55
Q

Atypical mumps means

A

Directly meningitis without parotid involvement

56
Q

Diagnosis of Mumps

A

Antigen
Antibody - ELISA
RT PCR
Culture/cell lines

57
Q

Recommended strain for Mumps vaccine

A

Jeryl Lynn strain

58
Q

Vaccines for Mumps

A

MMR
MMR-V - V is varicella

59
Q

B/L parotid gland involvement seen in case of Child and adult smoker

A

Child - Mumps
Adult smoker - Warthin’s tumor

60
Q

Types of Respiratory Synctial virus and which one is more severe

A

RSV A and B
RSV A - More severe

61
Q

Clinical features seen RSV infection in infants and adults

A

Infants - M/C cause of Lower resp tract infection - Fever, Rhinorrhea, Cough,Dyspnea, Wheezing
Adults - causes Upper resp tract infection

62
Q

Age group mostly affected by RSV virus

A

6 weeks to 6 months

63
Q

Microscopic finding in case of RSV infection

A

Giant cells

64
Q

Which is most sensitive diagnosis method for RSV infection

A

Virus isolation - on HeLa , Hep2

65
Q

Cytopathic effect seen in case of RSV infection

A

Synctium formation - Multinucleated giant cell

66
Q

Treatment of RSV infection

A

Newer drug - Palivizumab (against Fusion protein)
For severe infections - Ribavirin

67
Q

RSV infection is more common in which season

A

Rainy

68
Q

Parainfluenza virus is commonly seen in which season

A

Worldwide winter

69
Q

Clinical features in Parainfluenza infection

A

M/C symptom - common cold
Children - Croup
Severe cases - Pneumonia

70
Q

Most common complication of Parainfluenza virus

A

Otitis media

71
Q

Clinical features of Nipah virus infection

A

Encephalitis
Fever

72
Q

Nipah virus Mnemonic

A

NIPAH
N- Nervous System - 60-70% mortality
P - Pigs (amplifier)
Animal - Human

73
Q

Vector in case of Nipah virus infection

A

Fruit bat

74
Q

Transmission of Nipah virus and it’s amplifier

A

Bat’s urine contaminating food and water
Patient secretions
Amplifier - Pigs