Iahi: 3.06 - Respiratory Viruses

Front 1

What viruses cause respiratory infections and diseases?

Back 1

- Influenza virus
- Rhinovirus
- Coronavirus
- Parainfluenza Virus
- Respiratory Syncytial Virus (RSV)
- Metapneumovirus
- Adenovirus (sometimes)

Front 2

What cells are infected by influenza virus? How are these cells destroyed/damaged?

Back 2

- Ciliated epithelial cells lining upper resp. tract, trachea, and bronchi
- Virus replication and cytotoxic T lymphocytes damage and destroy respiratory epithelium

Front 3

How long is the incubation period for influenza virus?

Back 3

Short ~24 hours

Front 4

What are the symptoms of influenza virus infection in adults?

Back 4

- Rapid onset of fever
- Malaise
- Myalgia
- Sore throat
- Non-productive cough

Front 5

What are the symptoms of influenza virus infection in children?

Back 5

- Similar to adults
- Higher fever
- GI symptoms (abdominal pain and vomiting)
- Otitis media
- Myositis
- Croup

Front 6

What are the complications of influenza virus infection?

Back 6

- Primary viral pneumonia
- Secondary bacterial pneumonia
- Myositis and cardiac involvement
- Neurological syndromes: Guillain-Barré Syndrome, Encephalopathy, Encephalitis, Reye Syndrome

Front 7

How do you diagnose influenza infection?

Back 7

- Rapid antigen capture (detects Nucleoprotein, NP, ~15 min.)
- RT-PCR

Front 8

Where does influenza virus replicate cellularly? What kind of genome?

Back 8

- Replicates, transcribes in nucleus (unusual)
- (-) ssRNA

Front 9

What kind of drugs are used to treat influenza infections and what are their targets? 3 groups

Back 9

- Zanamivir and Oseltamivir (NA inhibitors)
- Previously Amantadine and Rimantadine (block M2 proteins - inhibits uncoating)
- Ribavirin (inhibits viral RNA synthesis)

Front 10

What kind of vaccines are used to prevent influenza infections? [2]

Back 10

- Formalin inactivated (mix of prevalent antigenic types)
- Attenuated infectious viruses (intranasal and must be kept cold)

Front 11

What is the cause of 50% of common colds? Type - genome?

Back 11

Rhinovirus (Picornavirus = +ssRNA icosahedral)

Front 12

What causes the symptoms of Rhinoviruses?

Back 12

Inflammatory response - infected cells in nose release bradykinin and histamine --> nasal discharge, sore throat, cough, headache

Front 13

What are the temperature considerations of Rhinovirus? Coronoviruses?

Back 13

- Rhinoviruses - grow better at 33 degrees than 37 degrees (sensitive to fever)
- Coronoviruses - grow better at 33 degrees to 35 degrees

Front 14

What immune response is important for limiting re-infection of rhinoviruses?

Back 14

Secretory IgA

Front 15

How are Rhinoviruses transmitted between people?

Back 15

Directly from individual to individual via respiratory secretions (via fomites - door handle, silverware, etc)

Front 16

How do you treat / prevent Rhinoviruses?

Back 16

No effective prevention and control measures yet

Front 17

What is the cause of 10-15% of common colds? Genome?

Back 17

Coronaviruses = +ssRNA (helical)

Front 18

What cells are affected by Coronaviruses? Symptoms?

Back 18

- Epithelial cells of upper respiratory tract
- Watery eyes, sneezing, nasal congestion, sore throat, sometimes fever, chills, headache, other aches, cough

Front 19

What is the cause of SARS? genome?

Back 19

- Coronavirus - +ssRNA helical
- Originated from virus in horseshoe bats in China

Front 20

How was SARS (Coronavirus) spread? 2

Back 20

Face-to-face contact (virus in respiratory secretions and feces)

Front 21

How are Coronoviruses (common cold and SARS treated)?

Back 21

No vaccines available or efficacious therapies

Front 22

What diseases / viruses are caused by "Paramyxoviruses"? Way to remember? Genome?

Back 22

- Parainfluenza (croup)
- RSV (Respiratory Syncytial Virus)
- Mumps and Measles
PaRaMyxovirus
- (-)ssRNA helical

Front 23

What are the important surface proteins on Paramyxoviruses ? [3]

Back 23

- F = Fusion protein (for virus entry)
- HN = Hemagglutinin (viral attachment) and Neuraminidase (viral release)
** HN Not on RSV

(Parainfluenza, RSV, Mumps, Measles)

Front 24

How are Parainfluenza viruses (Paramyxoviradae) spread? When are they more common?

Back 24

- Respiratory secretions
- Fall and winter, common nosocomial infection (hospital acquired)

Front 25

What cells are affected by a Parainfluenza infection (Paramyxoviradae)? Symptoms?

Back 25

- Infect epithelial cells in upper respiratory tract
- Lower respiratory complications in infants and young children, CROUP, subglottal swelling may close airway

Front 26

What virus causes CROUP?

Back 26

Parainfluenza (Paramyxovirus)

Front 27

What are the types of Parainfluenza viruses? Differences?

Back 27

- Types 1, 2, 3 - resp. tract disease ranging from mild common colds to bronchiolitis an/or pneumonia
- Type 4 - usually mild

Front 28

What protects from Parainfluenza infection? what is its target?

Back 28

IgA (against HN - hemagglutinin/neuraminidase) in nasal secretions (short-lived protection)

Front 29

What patient population is affected more severely by Parainfluenza infections?

Back 29

Children w/ T cell deficiencies

Front 30

What is the most common cause of fatal acute respiratory tract infection in infants and young children?

Back 30

RSV (Respiratory Syncytial Virus) - type of Paramyxovirus

Front 31

How common is RSV (Respiratory Syncytial Virus)? when is it most severe?

Back 31

Infects virtually everyone by age 2; re-infections occur throughout life and can be sever in elderly

Front 32

Where does RSV (Respiratory Syncytial Virus) - type of Paramyxovirus infect? Symptoms?

Back 32

- Localized infection of respiratory tract
- No viremia or systemic spread
- Pneumonia from cytopathologic spread of virus (syncytia), Bronchiolitis (by immune response)
- Typical "giant cells" lead to airway obstruction

Front 33

Can you be protected from RSV (Respiratory Syncytial Virus) - type of Paramyxovirus infection?

Back 33

- Maternal antibody does not protect infant (hence most common cause of fatal acute resp. tract infxn in infants and young children)
- Natural infection does not prevent re-infection

Front 34

What type of immune response to RSV (Respiratory Syncytial Virus) - type of Paramyxovirus is mediated by adults? Infants?

Back 34

- Adults - Th1 response --> IFN-γ --> activates macrophages, NK cells, CMI and B cells
- Infants - Th2 response --> IgG4, IgG1, IgE and IL-4 lead to mast cell degranulation, IL-5 leads to eosinophilia and wheezing

Front 35

What are the symptoms of RSV (Respiratory Syncytial Virus) - type of Paramyxovirus infection for children <1 yo, children, older children and adults?

Back 35

- <1 yo - fever, cough, dyspnea, cyanosis
- Children - febrile rhinitis and pharyngitis
- Older children and adults - common cold

Front 36

How do you treat healthy infants, premature or immunocompromised infants, and premature infants with RSV (Respiratory Syncytial Virus) - type of Paramyxovirus? is there a vaccine?

Back 36

- Healthy infant - supportive tx, oxygen, IV fluids, nebulized cold stream
- Premie or Immunocompromised - aerosolized ribavirin
- Premie - passive immunization w/ anti-RSV Ig and humanized monoclonal Abs
* NO vaccine *

Front 37

What are the symptoms and treatments for Metapneumovirus (Paramyxovirus)? where is the infection located?

Back 37

- Acute respiratory illness similar to RSV (most severe cases seen in infants, elderly, and immunocompromised)
- Upper RTI - common cold, bronchitis, wheezing, pneumonia
- No vaccine or antiviral therapies
- Most children infected by 5 yo

Front 38

What are the two emerging respiratory viruses with high mortality rates? where did they come from?

Back 38

Hendra and Nipah virus - Paramyxoviruses (jumped from bats to people)

Front 39

What kind of viruses are Adenoviruses? Symptoms? are they systemic?

Back 39

- DS linear DNA virus
- Respiratory infection (pharyngitis), conjunctivitis (pink eye), GI infections, hemorrhagic cystitis (inflam. of urinary bladder)
- Resp. infections --> systemic infections (viremia) in immunocompromised

Front 40

What can happen to the respiratory tract when infected with Adenovirus?

Back 40

- Destructive productive infection
- Persistent infection w/ virus shedding
- Latent infections in lymphoid tissues like tonsils or adenoid tissue

Front 41

What populations of patients are Adenovirus infections associated with? [2]

Back 41

- Military recruits - acute respiratory disease
- Children / bone marrow transplant recipients - acute hemorrhagic cystitis

Front 42

How are Adenoviruses spread?

Back 42

- Aerosol, close contact, or fecal-oral
- Fingers spread virus to eyes (conjunctivitis)

Front 43

What types of cells are affected by Adenoviruses?

Back 43

- Mucoepithelial cells in respiratory tract, GI tract, conjunctiva or cornea
- Persists in lymphoid tissue (e.g., tonsils, adenoids, Peyer patches)

Front 44

What immune responses are important for Adenoviruses? [2]

Back 44

- Antibody is important for prophylaxis and resolution
- Cell-mediated immunity also important

Front 45

is viremia popular in influenza

Back 45

not really

Front 46

how does amantadine and rimantadine work on influenza strains

Back 46

block M2 protein and inhibiting viral uncoating

Front 47

how does Ribavirin treat influenza

Back 47

inhibits synthesis of viral RNA

Front 48

how does Zanamivir and Oseltamivir treat influenza

Back 48

they are neuraminidase inhibitors

Front 49

what does SARS stand for

Back 49

sudden acute respiratory syndrome

Front 50

what does MERS stand for? how is it different from SARS? [2]

Back 50

Middle East Respiratory Syndrome

different genome that SARS, can infect more than just humans; Bats, Camels

Front 51

what virus causes Measles

Back 51

Morbillivirus

Front 52

what virus causes Hendra or Nipah? what type of virus class does it belong to

Back 52

Henipavirus [a paramyxoviridae]

Front 53

what does HPIV stand for? what is the difference in infection btw HPIV 1-4?

Back 53

Human parainfluenza virus

1,2= infect later in life, cause Croup.

3= a lower respiratory virus common in 1st yr of life

4= usually asymptomatic or mild

Front 54

does paramymixoviruses go to viremia?

how is Bronchitis caused?

pneumonia caused?

Back 54

not viremia or systemic

-bronchitis is an immune response

-pneumonia= cytopathogenic effect [infected cells of URT fall into lower tract and cause pneumonia?

Front 55

between adults and children, who is more likely to produce a histamine/prostiglandin D2 response to RSV? Why?

Back 55

Children, they have the Th2 tract activated by the virus

Front 56

what does hMPV stand for? who does it infect/where?

Back 56

human Metapneumovirus: is a L-RTI for children. second most common LRTI, to RSV

Front 57

can Adenoviruses go systemic? is there an immunization available?

Back 57

yes -

immunization only available for military recruits