Virology (24) - Coronaviridae & Orthomyxoviridae

Front 1

Are Coronaviridae enveloped or naked?

Back 1

enveloped.

Front 2

Describe the shape of the Coronaviridae nucleocapsid.

Back 2

helical

Front 3

Coronaviridae are so called because projections from the envelope create a "corona."

What are these projections?

Back 3

viral glycoproteins

Front 4

Describe the genome of Coronaviridae.

Back 4

large (+) ssRNA

Front 5

How large are Coronaviridae virions?

Back 5

80-160 nm (medium)

Front 6

Coronaviridae genome sizes range from 25-30 kbp, making them the ____ RNA viruses.

Back 6

largest

Front 7

There are ____ strains of human coronavirus, but many serotypes.

Back 7

two

Front 8

Coronaviruses are the #___ cause of the common cold.

Back 8

#2 cause

Front 9

Corona viruses are responsible for 10-15% of ____ ____ ____ ____.

Back 9

upper respiratory tract infections

Front 10

Can gastroenteritis be caused by coronaviruses?

Back 10

yes - although the viruses are enveloped, they are very durable and can withstand conditions of the GI tract.

Front 11

When might one use diagnostic testing when coronavirus is suspected?

Back 11

SARS

Front 12

Coronavirus grows best in what temperature range?

Back 12

33-35 C (low)

Front 13

What is the primary tissue infected by coronaviruses?

Back 13

epithelial cell of the upper respiratory tract

Front 14

Are coronavirus infections generally strong or mild?

Back 14

mild - except SARS

Front 15

SARS stands for...

Back 15

Severe Acute Respiratory Syndrome

Front 16

Coronavirus - Diagnostics

Back 16

serology used to detect antibody in acute verses convalescent sera (most adults already seropositive)

virus isolation difficult, but not impossible

Front 17

Coronavirus - Treatment? Vaccine?

Back 17

No antiviral or vaccine available for humans.

Are animal coronavirus vaccines

Groups working on SARS vaccine

Front 18

Orthomyxoviridae - enveloped or naked?

Back 18

enveloped

Front 19

Orthomyxoviridae - describe nucleocapsid.

Back 19

spherical or tubular nucleocapsid

Front 20

Orthomyxoviridae - virion size?

Back 20

80-120 nm across

Front 21

Orthomyxoviridae - genome

Back 21

segmented, (-) ssRNA

Front 22

How many segments in Influenza A, B and C?

Back 22

A & B - 8
C - 7

Front 23

Name two important matrix proteins carried in the Orthomyxoviridae virion.

Back 23

M1 & M2

Front 24

Orthomyxoviridae - nucleoprotein

Back 24

made up of four viral proteins complexed with RNA

Front 25

Name the two envelope proteins studded in the Orthomyxoviridae membrane.

Back 25

HA (haemagglutinin)
NA (neuraminidase)

Front 26

HA (haemagglutinin) - function

Back 26

viral attachment protein

Front 27

NA (neuraminidase) - function

Back 27

multifunctional protein involved in virus egress as well as facilitating infecting by dissolving mucous

Front 28

Orthomyxoviridae - where does replication take place?

Back 28

nucleus

Front 29

How are influenzas named?

Back 29

H(#)N(#)

H = HA
N = NA

Front 30

Which antigens are used to differentiate Influenza into strains A, B or C?

Back 30

M1 - matrix protein
M2 - membrane protein (ion channel)
NP - nucleoprotein (type specific antigen)

Front 31

M1

Back 31

matrix protein

Front 32

M2

Back 32

membrane protein (ion channel)

Front 33

NP

Back 33

nucleoprotein (type specific antigen)

Front 34

What are the three important family members of Orthomyxoviridae?

Back 34

Influenza A (bird)
Influenza B (only human)
Influenza C (not a sig pathogen)

Front 35

Describe influenza virus classification.

Back 35

Type (A,B,C) / Place of isolation / Date of isolation / HA and NA antigens (for A)

Front 36

Do orthomyxoviruses cause disease through direct or indirect methods?

Back 36

both

Front 37

What are the direct pathological effects of Orthomyxovirus infection?

Back 37

Cytolysis of epithelial cells of URT (ciliated & goblet cells)

Front 38

What enzyme is used by Orthomyxoviruses to break down mucous?

Back 38

viral neuraminidase

Front 39

How are Orthomyxoviruses released?

Back 39

apical release of virus from infected cell

Front 40

What are some possible complications of Orthomyxovirus infection?

Back 40

pneumonia and Reye's Syndrome (encephalitis)

**infection destroys epithelium & promotes secondary bacterial infection.

Front 41

What is the #1 viral killer in the US?

Back 41

influenza

Front 42

Influenza A - disease course

Back 42

- 1-4 day incubation
- prodrome (malaise & headache that last a few hours)
- followed by acute onset of fever, myalgia and non-productive cough
- symptoms for 3 days with full recovery in 7-10 days

Front 43

What symptom is an indication that a pt has progressed from Influenza A to a secondary disease?

Back 43

purulent sputum is usually present --> productive cough.

Front 44

Why is secondary disease common with influenza infection?

Back 44

Once the epithelial cells are damaged, pt is vulnerable to bacterial infections.

Front 45

In a pt with influenza A, ____ ____ may develop if pt takes aspirin.

Back 45

acute encephalitis

Front 46

How many people in the US have influenza A each year?

Back 46

10-20%

Front 47

During an influenza pandemic year, morbidity may be >__% and mortality >____ (in US).

Back 47

50, 5,000

Front 48

The most mortality from influenza occurs in the ____ ____.

Back 48

elderly population

Front 49

Who is at particular risk rom influenza?

Back 49

>65yo
very young
immunocompromised
chronic pulmonary or cardiac disease (asthmatics, smokers, emphysema, etc)

Front 50

When is flu season in OK?

Back 50

mid-November to early April

Front 51

Influenza A
Each RNA segment encodes a ____ ____.

Back 51

single protein

Front 52

Influenza A
Segment 4 is __ and segment 6 is __.

Back 52

4=HA
6=NA

Front 53

Influenza A
Entire genome is __ segments, but virons tend to have __-__ due to what?

Back 53

8
10-11
packaging redundancy

Front 54

Influenza A
Reassortment occurs during a ____ _____.

Back 54

mixed infection (with different strains of Influenza A)

Front 55

Complete change in one or more viral proteins is called "____ ____" and happens due to reassortment.

Back 55

antigenic shift

(**big change)

Front 56

Whenever Influenza A undergoes an antigenic shift, a ____ or ____ is possible.

Back 56

epidemic/pandemic

Front 57

The RNA-dependent RNA polymerase that orthomyxoviruses use for genome replication is very error prone and generates point mutations in genes, including HA and NA.

This slow change in viral antigens is called ____ ____.

Back 57

antigenic drift

Front 58

How is influenza A usually diagnosed?

Back 58

by pt symptoms coinciding with local outbreak

Front 59

Why is it important to do diagnostic test on infants when Influenza is suspected?

Back 59

need to differentiate from RSV

Front 60

What test can be used to diagnose Influenza A?

Back 60

Serology (not common)
Hemadsorption tests
Direct MAB Immunofluorescence
Hexaplex PCR assay

Front 61

Influenza A
Treatment Options

Back 61

Amantidine & Rimantidine, Ribovarin, Zanamivir & Oseltamivir

Front 62

What do Amantidine and Rimantidine act on?

Back 62

viral M2 proteins - block ion channel activity, penetration & uncoating

Front 63

Influenza A & B
Treatment Options

Back 63

Zanamivir & Oseltamivir

inhibit viral neuraminidase enzyme (needed for viral release)

**prophylactic

Front 64

Ribovarin

Back 64

Requires aerosol inhalation (apparatus)

Used with infants with respiratory syncytial virus (RSV)

**only used in pts with severe respiratory distress

Front 65

Influenza - Immunization

Back 65

killed or live, mix of A & B strains

updated every year