23 - Respiratory Infections Caused by Viruses Flashcards

1
Q

How are the folowing respiratory viruses spread?

Rhinovirus

Enteroviruses

Coronavirus

Parainfluenzavirus

Respiratory Syncytial Virus

Metapneumovirus

Infleunza Virus

Adenovirus

A

Respiratory transmission leads to repication in the upper respiratory tract which leads to upper and sometimes lower respiratory infections and diseases

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2
Q

How are the following viruses spread?

Enteroviruses

Measles virus

Adenovirus

A

Respiratory transmission leads to replication in upper respiratory tract

which can lead to respiratory disease (some serious like pneumonia) or to viremia which will then target organs and symptoms

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3
Q

What time of year do people get Rhinovirus?

A

March to October

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4
Q

What time of year do people get coronavirus?

A

December through April

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5
Q

What time of year do people get Enterovirus?

A

June through October

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6
Q

What time of year do people get Adenovirus?

A

ALL YEAR!

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7
Q

What time of year do people get Parainfluenza Virus?

A

PIV-3 is March through July

PIV 2, 3 is August though November

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8
Q

What time of year do people get Respriatory Syncytial Virus?

A

November though May

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9
Q

What time of year do people get Influenza?

A

November through March

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10
Q

What time of year do people get Metapneumovirus?

A

ALL YEAR!

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11
Q

How does Rhinovirus accomplish antigenic diversity and how many serotypes are identified? Who can be infected with it? WHt temps does ti grow best at?

A
  • Genetic variation leadsing to antigenic diversity-150 sertypes identified RV-A (75 type), RV-B (25 types), RV-C (51 types)
  • humans are only host
  • grows at 33-37 degrees
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12
Q

How is Rhinovirus transmitted? How do we prevent adn control it?

A
  • transmitted by respiratory secretions directly from person to person via fomites
  • Prevention and control are maintained by hand washing and disinfectants, there is not a vaccine
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13
Q

What are Rhinoviruses the major cause of? How do Rhinoviruses infect/cause damage?

A
  • Rhinoviruses cause the majority of common colds
  • Rhinovirus infects a relatively small proportion of the cells lining the nose and other upper respiratory epithelium therefore memebrane damage is mild
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14
Q

How do Rhinoviruses cause symptoms? How is it treated?

A

cold symptoms are due to the body’s response to infection

immune response= induction of inflammaotry mediators (histamine, kinins, interluekins, prostaglandins) resulting in dilation and leakage of blood vessels and mucus secretions, along with activation of sneeze and cough reflexes

Most rhinovirus infections are mild and self limiting. complications are exacerbations of reactive ariway diseases (asthma, COPS, otitis media, sinusisits chronic bronchitis)

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15
Q

How are enteroviruses often transmitted? What does it lead to? what are complications is there a vaccine?

A
  • transmitted mainly via respiraotry route (ex: enterovirus D68 and some enterovirus C types)
  • colds and “flu” like symptoms
    • common cold symptoms, fever, headache
  • comlicationsL serious respiratory disease, sstemic disease
  • no vaccine or antiviral therapy available
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16
Q

What are symptoms of Acute Flaccid Myelitis (AFM)? What virus is it associated with?

A
  • weakness
  • loss of muscle tone
  • facial droop
  • difficulty swallowing
  • slurred speech
  • paralysis

Enterovirus EV D68 is associated with this

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17
Q

What does Coronavirus cause? What are the symptoms? Is there a vaccine? anatomically where does it infect?

A
  • common cold! (second most prevalent cause representing 10-15% of total)
  • watery eyes, sneezing, nasal congestion, sore throat, sometimes fever, chills, headache, other aches, cough
  • disease limited to upper RT infects epithelial cells (optimal temp is 33-35)
  • no vaccine
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18
Q

WHat are the 3 Coronaviruses that cause severe respiratory illness?

A

SARS-CoV

MERS-CoV which causes acute pneumonia and renal failure

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19
Q

Who does Middle East Respiratory Syndorme (MERS-CoV) infect?

A

humans, bats, camels

does not pass from person to person easily

acute pneumonia and renal failure

20
Q

What are the 4 types fo Parainfluenza virus? Who does it infect?

A

Lower respiratory complications in infants and young children; CROUP subglottal swelling may close airway

  • Types 1 and 2 are common cause of croup
  • Type 3 is similar to RSV in that it is a common cause of bronchiolitis in infants
  • Type 4- usually mild disease
21
Q

What are the symptoms of croup and is there a vaccine for Parainfluenza virus?

A

NO vaccine!

  • URI-like symptoms
  • Barking, seal-like cough
  • inspiratory stridor
  • symptoms worse at night
  • hypoxia uncommon
  • steele sign on radiograph
22
Q

Where does Respiratory syncytial virus infect? What does it cause?

A
  • localized infection of respiratory tract, no systemic spread
    • Bronchiolitis, pneumonia or both- pneumonia more common in elderly/immunocompromised
    • febrile rhinitis and pharyngitis-children
    • common cold-older children and adults
  • blockage of narrow airways of infants
    • vius induced CPE includes syncytia (multinucleated cells)
    • induction of inflammatory cytokines
23
Q

Who does RSV infect and during what time of year? Why are there evaccine challenges

A
  • Infects virtually everyone by age 2
    • different disorders are associated with different ages (see attached image)
  • outbreaks during winter months
  • natural infections do not prevent re-infection, infections throughout life, can be severe in the elderly which presents vaccine challenges
24
Q

how do we treat an otherwise healthy infant with RSV? How about a premature or immunocompromised infant?

A
  • otherwise healthy infant: treatment si supportive, oxygen, IV fluids, nebulize cold steam
  • premature or immunocompromised infants: aerosolized ribavirin, passive immunization with anti-RSV Ig and humanized monoclonal antibodies against viral fusion protein
25
Q

Is there a vaccine currently approved for RSV?

A

No vaccine currently approved but many are in clinical trial! (aka probs NOTT but here is the card anyway <3 DO i hear automatic 5 anyone?)

  • inactivated vaccines have shown poor results with increased disease severity upon natural infection
  • live attenuated vaccine have no increase in disease severity with natural infection but poor long term protection
  • additional vaccine partices
    • nanopartices F protein
    • subunit F protien
    • Enhancing maternal immunity
26
Q

Who gets Metapneumovirus and to what virus does it have a similar spectrum of disease? What is it the 2nd most common cause of? At what age do people usually get it?

A
  • clinical spectrum of disease is similar to RSV but in general milder, with the most severe disease seen in infants, the elderly and immunocompromised
  • 2nd most common cause (after RSV) of lower respiratory tract infection in young children
  • by 5 yrs most children seropositive, re-infection common later in life
27
Q

How do we identify Metapneumovirus? Is there a vaccine?

A

Identified by RT-PCR

No vaccine or antiviral therapies available; approaches similar to RSV for treatment, emphasizing anti-fusion protein immunity

28
Q

What does it mean to say that influenza has genetic variation?

A
  • the flu has genetic variation which means antigenic differneces
    • 16 subtypes of hemagglutinin (HA)
    • 9 subtpes of neuraminidase (NA)
29
Q

What is the difference between antigenic shift and antigenic drift?

A

drift is small changes/mutations

shift is a whole new subtype! Big changes!

30
Q

What is the pathogenesis of Influenza? Where does it infect?

A
  • it is an acute respiratory disease
  • virus infects epithelial cells lining the upper respiratory tract, trachea, bronhi
  • virus replication-destruction of respiratory epithelium
  • cell damage also due to virus activated cytotoxic cells
  • viremia is NOT involved in the pathogenesis
31
Q

What does influenza do to normal tracheal mucosa and what does this lead to?

A

destruction of epithelial cells and cilia! leading to…

decreased clearance

risk of bacterial infection

viremia rare

32
Q

How long does influenza last? What is the major cause of death?

A
  • influenza is self-limiting so it usually lasts 3-7 days bu is more severe in young and old patients
  • secondary bacterial infections are the major cause of death
    • streptococcus pneumoniae
    • staphylococcus aureus
    • heamophilus influenzae
33
Q

What are 4 rare complications of influenza?

A
  • myositis and cardiac involvement
  • Guilain Barre syndrome
  • encephalitis
  • reye syndrome
34
Q

What are the 3 kinds of vaccines for influenza virus?

A
  • chemically inactivated-mixture of prevalent antigenic types (hemagglutinin and neuraminidase)
  • attenuated infectious viruses- intranasal administration
  • quadrivalent vaccine available in 2013
35
Q

What are the 3 antiviral therapies are available to treat influenza?

A
  • amantadine adn rimantadine- inhibit uncoating by blocking M2 protein (currentl not used due to high degree of antiviral resisitance)
  • Zanamivir (relenza) and oseltamivir (tamiflu) neuraminidase inhibitors inhibit the release of progeny virus
  • Baloxavir marboxil (xofluza) new! cap dependet endonuclease inhibitor that inhibits “cap snatching”
36
Q

What does adenovirus cause? What does ti cause in immunocompromised people? What does it cause in the respiratory tract?

A
  • a wide specturm of disease including respiratory infection (pharyngitis), conjuctivitis, GI infections, hemorrhagic cystisis (inflamamtion of bladder)
    • in immunocompromised causes systemic infections
  • In respiratory tract, can cause destructive productive infection, persistent infection with virus shedding, or latent infections in lymphoid tissues liek tonsils or adenoid tissue
37
Q

Is there a vaccine for adenovirus? How do we treat severe adenovirus that is found in the immunocompromised?

A

Not for gneral public, but yes for military recruits (adenovirus type 4 and 7)

Cidofovir used to treat severe infection in immunocompromised people

38
Q

What 3 adenovirus strains are associated with severe infection? What strains cause Pharyngoconjunctival fever?

A
  • serious infection (often pneumonia): adenovirus 14 , 4 and 7
  • Pharyngoconjunctival fever: adenovirus 1-7
    • elementary school kids with red eyes, sore throat, and fever
39
Q

What 2 virus families and associated viruses are DNA viruses? Are these viruses enveloped or naked?

A
  • Adenoviridae family is naked capsid (Adenovirus)
  • Herpesviridae family is enveloped (EBV, HHV-6, CMV, HSV)
40
Q

What 4 Virus families and associated viruses are RNA viruses? are they positive sens or negative sense? Are the naked or enveloped?

A
  • Picornaviridae: Rhinovirus, Coxsackie virus, echovirus, enterovirus
      • RNA, Naked
  • Coronaviridae: Coronavirus, SARS-CoV, MERS-CoV
    • +RNA, Enveloped
  • Orthomyxoviridae: Influenza A, B, C virus
    • -RNA, Enveloped
  • Paramyxoviridae: Parainfluenza virus, respiratory syncytial virus, metapneumovirus, measles virus
    • -RNA, Enveoped
41
Q

Most respiratory infectious are caused by _______

A

viruses

42
Q

_________are the most common illnesses resulting in missed school or work

A

respiratory infections

43
Q

Most of the viruses that cause respiratory disease are ______-

A

Most of the viruses that cause respiratory disease are localized rather than systemic infections

44
Q

It has been difficult to develop effective vaccines against respiratory viral pathogens due to_________

A

their genetic variability and our ability to elicit protective immunity

45
Q

______ and _______ individuals tend to be the most severely affected by respiratory viral pathogens

A

very young and elderly individuals tend to eb the most severely affected by respiratory pathogens