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Flashcards in Respiratory Viruses Deck (39)
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1
Q

What conditions are caused by upper respiratory virus infections?

A
  • Sinusitis
  • Common cold
  • Pharyngitis
  • Epiglottitis
  • Laryngotracheitis
2
Q

What conditions are caused by lower respiratory virus infections?

A
  • Bronchitis
  • Bronchiolitis
  • Pneumonia
3
Q

Which respiratory viruses have viremia that targets organs?

A

Measles virus

Adenovirus

Enteroviruses

4
Q

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

A

16; 9

5
Q

Explain genetic drift

A
  • 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
6
Q

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

A
  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
7
Q

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

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

A

H5N1 and H7N9

Theses strains do not transmit easily among people

8
Q

How does influenza lead to cell damage?

A
  • 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
9
Q

Why are those with influenza virus predisposed to bacterial superinfection?

A

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

10
Q

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

A

Streptococcus pneumoniae

Staphylococcus aureus

Haemophilus influenzae

11
Q

What are some rare complications of Influenza?

A
  • Myositis and cardiac involvement
  • Guillain-Barre syndrome
  • Encephalitis
  • Reye syndrome
12
Q

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

A
  • Formalin inactiavted - mixture of prevalent antigenic types
  • Attenuated infectious viruses - intranasal admin.
  • Quadrivalent vaccine (2013)
13
Q

What are some forms of antiviral therapy for influenza?

A
  • Amantadine and remantadine - inhibit uncoating by blocking M2 protein
  • Zanamivir (Relenza) and Oseltamivir (Tamiflu) neuraminidase inhibitors (inhibit release of progeny virus)
14
Q

Rhinovirus is the cause of __% of colds

A

50

15
Q

How is rhinovirus transmitted?

How many serotypes have been identified?

A
  • Transmission by respiratory secretions
    • directly from individual to individual
    • via fomites
  • 150 serotypes identified
16
Q

What vaccines and antivirals exist for Rhinovirus?

A

none

17
Q

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

A

Enterovirus

18
Q

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

A

Poliovirus

Coxsackie A virus

Coxsackie B virus

Echovirus

*no vaccine or antiviral therapy

19
Q

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

A

ED-D68

20
Q

Coronavirus causes __-__% of common colds

A

10-15%

21
Q

Coronavirus diseases are limited to which part of the airway?

A

upper RT

22
Q

What are two recently identified coronaviruses that cause respiratory illness?

A

2002-2003 - SARS outbreak caused by SARS-CoV

2012 - Acute pneumonia and renal failure - MERS-CoV

23
Q

SARS (Sudden acute respiratory syndrome)

  • What is the fatality rate among people with the ilness?
  • How is it transmitted?
  • What is the source?
A
  • 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
24
Q

MERS (Middle East Respiratory Syndrome)

  • Species ifnected?
  • Illness?
  • Transmission?
A
  • Species ifnected?
    • bats, camels
  • Illness?
    • Acute severe pneumonia and renal failure
  • Transmission?
    • Does not pass from person to person readily
    • Non-socomial infections documented
25
Q

Parainfluenza virus

  • When do infections usually occur?
  • What lower respiratory complication is prevalent in infants and young children?
A
  • 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)
26
Q

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

A
  • 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
27
Q

How might you identify a toddler with croup?

A
  • grumpy
  • little appetite
  • soar throat
  • sound of a barking seal
  • flaring of nostrals
  • high pitched noise (stridor)
28
Q

Respiratory syncitial virus is a _____ infection of the respiratory tract

A

localized (no systemic spread)

29
Q

How are the following groups treated for RSV?

Healthy infants:

Premature or immunocomrpomised infants:

Premature infants:

A

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

30
Q

Metapneumovirus

  • Clinical spectrum of disease:
  • How is it identified?
  • Vaccine?
A
  • 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
31
Q

Where do you find Hendra and Nipah virus?

A

Australia and Asia

32
Q

What respiratory diseases are associated with Adenovirus

A

Acute respiratory disease, sometimes serious (pneumonia)

33
Q

Adenoviruses 1-7 can cause…

A

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

34
Q

Adenovirus

  • Spectrum of disease:
  • What determines the disease?
  • Vaccine?
A
  • 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
35
Q

Measles virus

  • Symptoms:
  • Complications:
A

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

36
Q

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

A

pneumonia

37
Q

How is adenovirus different from RNA viruses?

A

It is the DNA virus family

38
Q

What are the human picornaviruses?

A

Enterovirus

Parechovirus

Heparnavirus

Rhinovirus

39
Q

What are the paramyxovaridae (human)

A

Movillivirus (measles)

Parmyxovirus (parainfluenza)

Pneumovirus (RSV)

Henipavirus (Hendra, Nipah)