Respiratory Viruses

Question 1

What conditions are caused by upper respiratory virus infections?

Answer 1

• Sinusitis
• Common cold
• Pharyngitis
• Epiglottitis
• Laryngotracheitis

Question 2

What conditions are caused by lower respiratory virus infections?

Answer 2

• Bronchitis
• Bronchiolitis
• Pneumonia

Question 3

Which respiratory viruses have viremia that targets organs?

Answer 3

Measles virus

Adenovirus

Enteroviruses

Question 4

Influenza viruses can have ___ subtypes of hemagglutinin (HA) and __ subtypes of neuraminidase (NA)

Answer 4

16; 9

Question 5

Explain genetic drift

Answer 5

• Influenza virus genes, made of RNA, are more prone to mutations than genes made of DNA
• If the HA gene changes, so can the antigen that it encodes, causing it to change shape
• If the HA antigen changes shape, antibodies that normally would match up to it no longer can, allowing the newly mutated virus to infect the body’s cells

Question 6

Explain the steps in genetic shift for influenza (using aquatic birds and humans)

Answer 6

1. An aquatic bird passes a bird strain of influenza to an intermediate host
2. A person passes a human strain of influenza to the same intermediate host (chicken or pig)
3. When the viruses infect the same cell, the genes from the bird strain mix with the genes from the human strain to yield a new strain
4. The new strain can spread from the intermediate host to humans

Question 7

Since 2003, what two avian influenza viruses have infected humans?

Why don’t they spread as quickly as other strains of the flu?

Answer 7

H5N1 and H7N9

Theses strains do not transmit easily among people

Question 8

How does influenza lead to cell damage?

Answer 8

• Virus infects ciliated epithelial cells lining the upper respiratory tract, trachea and bronchi
• Virus replication leads to destruction of respiratory epithelium
• Cell damage also due to virus activated cytotoxic T cells

Question 9

Why are those with influenza virus predisposed to bacterial superinfection?

Answer 9

Loss of natural barriers and exposure of binding sites on epithelial cells

Question 10

What secondary infections are the major cause of death in influenza?

Answer 10

Streptococcus pneumoniae

Staphylococcus aureus

Haemophilus influenzae

Question 11

What are some rare complications of Influenza?

Answer 11

• Myositis and cardiac involvement
• Guillain-Barre syndrome
• Encephalitis
• Reye syndrome

Question 12

What types of vaccines are use for prevention and control of influenza?

Answer 12

• Formalin inactiavted - mixture of prevalent antigenic types
• Attenuated infectious viruses - intranasal admin.
• Quadrivalent vaccine (2013)

Question 13

What are some forms of antiviral therapy for influenza?

Answer 13

• Amantadine and remantadine - inhibit uncoating by blocking M2 protein
• Zanamivir (Relenza) and Oseltamivir (Tamiflu) neuraminidase inhibitors (inhibit release of progeny virus)

Question 14

Rhinovirus is the cause of __% of colds

Answer 14

50

Question 15

How is rhinovirus transmitted?

How many serotypes have been identified?

Answer 15

• Transmission by respiratory secretions
  
  • directly from individual to individual
  • via fomites
• 150 serotypes identified

Question 16

What vaccines and antivirals exist for Rhinovirus?

Answer 16

none

Question 17

What virus is most likely responsible for a summer cold with fever, head ache, and fatigue?

Answer 17

Enterovirus

Question 18

What are four types of enterovirus and what vaccines are available against them?

Answer 18

Poliovirus

Coxsackie A virus

Coxsackie B virus

Echovirus

*no vaccine or antiviral therapy

Question 19

What type of enterovirus has been confirmed in 628 people since August 2014 and has caused one death?

Answer 19

ED-D68

Question 20

Coronavirus causes __-__% of common colds

Answer 20

10-15%

Question 21

Coronavirus diseases are limited to which part of the airway?

Answer 21

upper RT

Question 22

What are two recently identified coronaviruses that cause respiratory illness?

Answer 22

2002-2003 - SARS outbreak caused by SARS-CoV

2012 - Acute pneumonia and renal failure - MERS-CoV

Question 23

SARS (Sudden acute respiratory syndrome)

• What is the fatality rate among people with the ilness?
• How is it transmitted?
• What is the source?

Answer 23

• What is the fatality rate among people with the ilness?
  
  • 10%
• How is it transmitted?
  
  • Face-to-face contact, virus in respiratory secretions and feces
• What is the source?
  
  • Bats, and other sanimals sold in markets in China

Question 24

MERS (Middle East Respiratory Syndrome)

• Species ifnected?
• Illness?
• Transmission?

Answer 24

• Species ifnected?
  
  • bats, camels
• Illness?
  
  • Acute severe pneumonia and renal failure
• Transmission?
  
  • Does not pass from person to person readily
  • Non-socomial infections documented

Question 25

Parainfluenza virus * When do infections usually occur? * What lower respiratory complication is prevalent in infants and young children?

Answer 25

* When do infections usually occur? * Fall and winter * What lower respiratory complication is prevalent in infants and young children? * CROUP (subglottal swelling may close airway)

Question 26

What are the types of Parainfluenza virus and what illnesses are they associated with?

Answer 26

* Type I and Type 2 - common cause of croup * Type 3 - similar to RSV in that is a common cause of bronchiolitis in infants * Type 4 - usually mild disease

Question 27

How might you identify a toddler with croup?

Answer 27

* grumpy * little appetite * soar throat * sound of a barking seal * flaring of nostrals * high pitched noise (stridor)

Question 28

Respiratory syncitial virus is a _____ infection of the respiratory tract

Answer 28

localized (no systemic spread)

Question 29

How are the following groups treated for RSV? Healthy infants: Premature or immunocomrpomised infants: Premature infants:

Answer 29

Healthy infants: supportive, oxygen, IV fluids, nebulized cold steam Premature or immunocomrpomised infants: aerosolized ribavirin Premature infants: Passive immunization with anti-RSV Ig and humanized monoclonal antibodies \*no vaccine currently available

Question 30

Metapneumovirus * Clinical spectrum of disease: * How is it identified? * Vaccine?

Answer 30

* Clinical spectrum of disease: * Similar to RSV but generally milder, with most severe disease seen in infants, elderly and immunocompromised * Identified by RT-PCR * Vaccine? * No vaccine or antiviral therapies available

Question 31

Where do you find Hendra and Nipah virus?

Answer 31

Australia and Asia

Question 32

What respiratory diseases are associated with Adenovirus

Answer 32

Acute respiratory disease, sometimes serious (pneumonia)

Question 33

Adenoviruses 1-7 can cause...

Answer 33

Pharyngoconjunctival fever - sudden onset of red eyes, sore throat, fever

Question 34

Adenovirus * Spectrum of disease: * What determines the disease? * Vaccine?

Answer 34

* Spectrum of disease: * respiratory infection, conjunctivitis, GI infections * What determines the disease? * tissue tropism of specific serotype * Vaccine? * no adenovirus vaccine for public, but new attenuated vaccine against adenovirus types 4 and 7 for military recruits

Question 35

Measles virus * Symptoms: * Complications:

Answer 35

Symptoms: cough, conjunctivitis, coryza, photophobia Complications: otitis media, croup, pneumonia

Question 36

What is the most common cause of death in young children with measles?

Answer 36

pneumonia

Question 37

How is adenovirus different from RNA viruses?

Answer 37

It is the DNA virus family

Question 38

What are the human picornaviruses?

Answer 38

Enterovirus Parechovirus Heparnavirus Rhinovirus

Question 39

What are the paramyxovaridae (human)

Answer 39

Movillivirus (measles) Parmyxovirus (parainfluenza) Pneumovirus (RSV) Henipavirus (Hendra, Nipah)