Viruses Pg 3 - 7

Question 1

(1) Cough, runny nose -> generalized aches and muscle pain, fever

(possible nausea and vomiting in children probably due to fever)

(2) Incubation 1-2 days; symptoms 5-7 days (cough 7-14 days)

Answer 1

Influenza virus (Myxovirus)

Question 2

(3) Viral Pneumonia (about 10% of admissions) – high mortality
(4) Secondary Bacterial Pneumonia sometimes follows viral URT infections

b. Transmitted by droplets and contact (especially hands) and by inhalation

Answer 2

Influenza virus (Myxovirus)

Question 3

d. Virus Structure
(1) Core with 8 strands of RNA

(2) Envelope
(a) Lipid bilayer from previous host cell (animal specific or adapted to other types of cells)
(b) Hemagglutinin and Neuraminidase – used for attachment and virulence

(3) Matrix protein (capsid)

Answer 3

Influenza virus (Myxovirus)

Question 4

Influenza virus (Myxovirus) has a core with?

Answer 4

8 strands of RNA

Question 5

Describe the Influenza virus (Myxovirus) envelope

Answer 5

LIpid bilayer from the PREVIOUS host cell, which means its animal-specific or adapted to other types of cells

The envelope uses hemagglutinin and neuraminidase for attachment and virulence

Question 6

Hemagglutinin and Neuraminidase

Answer 6

envelope/virulence for Influenza virus (Myxovirus)

Also the surface antigens

Question 7

(1) Types based on surface antigens Hemagglutinin (H) and Neuraminidase (N)

(a) Animal strain based on original “source” of viral envelope
(b) Infectivity of animal virus to humans is due to adaptation to enter human cell membranes

Answer 7

Antigenic Types (A, B, C) types of Influenza virus (myxovirus)

Question 8

(a) Common human subtypes: H3N2, H1N1 (human strain)
(b) Numerous swine subtypes, some adapted to humans, e.g. 2009 H1N1 (highly transmissible)
(c) Numerous avian subtypes, some adapted to humans; e.g. emerging subtype H5N1, H7N9 (considered dangerous)

Answer 8

Type A influenza

Question 9

Influenza types B and C are antigenically ____?

Answer 9

Stable

Question 10

Virulence factors for flu?

Answer 10

Gene recombination and mutation

Hemagglutinin and Neuraminidase are factors both of attachment and cause some symptoms

Question 11

High rate of gene recombination and mutation – New major antigenic types and subtypes sweep the world every 2-4 years

Answer 11

virulence for Influenza virus (Myxovirus)

Question 12

Influenza virus (Myxovirus) Surface antigen changes due to:

Answer 12

gene recombination and gene mutation

Question 13

recombination of 8 strands of RNA

Answer 13

gene recombination

Influenza virus (Myxovirus)

Question 14

causes antigenetic shift and drift

Answer 14

Gene mutation

Influenza virus (Myxovirus)

Question 15

factors both of attachment and cause some symptoms

Answer 15

Hemagglutinin and Neuraminidase

Influenza virus (Myxovirus)

Question 16

(a) Animal-specific envelope (e.g. human strains infect humans; avian strains infects avians; swine strains)
(b) Surface antigen changes (e.g. Avian Influenza (H5N1)
(c) Adaptation of virus envelope to enter and replicate in human cell

Answer 16

Other virulence factors…

Influenza virus (Myxovirus)

Question 17

Antiviral (for influenza/myxovirus) medications available – start treatment within __ hours to be effective

Answer 17

48

Question 18

Vaccine for Influenza virus (Myxovirus)?

Answer 18

(1) Made with the most common 3 antigens
(2) Required annually to match antigenic strains moving toward USA (World Health Org., CDC, and DoD labs track location and movement of strains around the world)

Question 19

RNA viruses that cause common cold?

THESE THREE FOR COMMON COLD testing purposes

Answer 19

Rhinovirus, Respiratory Syncytial Virus (RSV), and Corona virus

Question 20

overall most prevalent agent (over 160 antigen types) of cold

Answer 20

rhinovirus

Question 21

Second most common agent of colds

Answer 21

corona virus

Question 22

(b) Multiple antigenic types (about 30 types)
(c) New Highly Virulent Variants in Recent Years

• SARS (Severe Acute Respiratory Syndrome) (several thousand cases, about 30% mortality)
• MERS-CoV (Middle East Respiratory Syndrome – Corona Virus) – severe acute respiratory illness (fever, cough, shortness of breath), several hundred persons ill and about 30% mortality since 2012 (mostly Jordan, Saudia Arabia); camels are likely source

Answer 22

corona virus

Question 23

aka Human Orthopneumovirus, - the primary agent of colds in infants and young children

Answer 23

Respiratory Syncytial Virus (RSV)

Question 24

(a) Hundreds (thousands ?) of antigenic types exist; Antigenic groups A and B
(b) Can cause severe infections
(c) Immunoglobulins are not necessarily protective against future infections
(d) Development of vaccine is very challenging

Answer 24

Respiratory Syncytial Virus (RSV)

Question 25

Rhinovirus, Respiratory Syncytial Virus (RSV), and Corona virus transmitted by?

Answer 25

Transmitted by droplets and contact (especially hands and eyes) and by inhalation of droplets

Question 26

a. Enveloped RNA virus - member of Paramyxovirus family; 4 antigenic types b. Causes croup, bronchitis, cold-like symptoms; especially in children

Answer 26

Parainfluenza virus

Question 27

Mostly bronchitis in children? Can be severe

Answer 27

Parainfluenza virus

Question 28

a. Enveloped RNA virus - member of Paramyxovirus family, subfamily Pneumovirus (discovered 2001) b. Causes upper and lower respiratory tract illness (very prevalent)

Answer 28

Human Metapneumovirus (hMPV)

Question 29

Human Metapneumovirus (hMPV) is or is not enveloped?

Answer 29

It is enveloped, dude

Question 30

(1) Common cold, bronchiolitis, PNEUMONIA, croup (2) Outbreaks primarily in late winter – early spring (3) Incubation 3-5 days; shedding for few weeks (4) Affects all ages; more frequent and more severe in young children (5) Similar signs/symptoms to RSV (same taxonomic family)

Answer 30

Human Metapneumovirus (hMPV)

Question 31

Outbreaks primarily in late winter – early spring? Shedding?

Answer 31

hMPV Human Metapneumovirus

Question 32

a. DNA Virus, non-enveloped (>50 types); members of the family Adenoviridae b. Etiologic agent of 5% to 10% of all viral infections (50% of infections before age 5)

Answer 32

Adenovirus

Question 33

Adenonvirus... DNA or RNA? Enveloped or non-enveloped?

Answer 33

DNA non-Enveloped

Question 34

(1) "Acute Respiratory Disease" in military recruits (80%) -- types 4, 7 (2) Conjunctivitis -- types 2,3,5,7,8,19,21,37 (3) Atypical pneumonia -- type 37 (4) Cold-like disease -- types 1, 2, 5, 6 (5) Gastrointestinal disease (15%) -- types 40, 41 (6) Also: Croup/Bronchitis, Sore Throat, Cystitis

Answer 34

Adenovirus

Question 35

50% of viral infections before age 5?

Answer 35

Adenovirus

Question 36

"Acute Respiratory Disease" in military recruits (80%) -- types 4, 7

Answer 36

Adenovirus

Question 37

viral conjuncitivitis?

Answer 37

adenovirus Less purulent than bacterial pinkeye