Viral Infection Of The Upper Respiratory Tract Flashcards

0
Q

What are the viral causes of the common cold?

A
Rhinovirus- 30-50%
Coronavirus- 10-15%
Influenza virus- 5-15%
RSV- 5%
Parainfluenza 5%
Adenovirus <5%
Metapneumovirus unknown
Unknown 20-30%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What is the impact of viral respiratory infections in the US?

A
  • colds: 62 million, 20 million schools are lost
  • flu: 36,000 dead, seasonal influenza hospitalized 200,000 more
  • croup: 125,000 children in hospital, nearly all children become infected with RSV by age 2, globally, RSV affects 64 million people and causes 160,000 deaths each year, parainfluenza virus now thought to be the primary cause of croup
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the frequent symptoms of a rhinovirus infection

A

Most-common cold
Occasional-exacerbation of chronic bronchitis and asthma
Infrequent- pneumonia in children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the frequent symptoms of a cornavirus infection?

A

Most- common cold
Occasional- exacerbation of chronic bronchitis and asthma
Infrequent- pneumonia and bronchioles is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the frequent symptoms of human respiratory syncytial virus infection?

A

Most- pneumonia and bronchiolitis in young children
Occasional- common cold in adults
Infrequent- pneumonia in elderly and immunosuppressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the most frequent symptoms for parainfluenza virus infection?

A

Most- croup and lower respiratory tract disease in young children
Occasional- pharyngitis and common cold
Infrequent- tracheobronchitis in adults, lower respiratory tract diseased in immunosuppressed patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the most frequent symptoms for adenovirus infection?

A

Most- common cold and pharyngitis in children
Occasional- outbreaks of acute respiratory disease in military recruits
Infrequent- pneumonia in children; lower respiratory tract and disseminated disease in immunosuppressed patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the frequent symptoms of influenza a virus?

A

Most-influenza
Occasional-pneumonia and excess mortality in high risk patients
Infrequent- pneumonia in healthy individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the symptoms of a influenza b infection?

A

Most- influenza
Occasional- rhinitis or pharyngitis alone
Infrequent- pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the features of a respiratory infection?

A
  • virions reach respiratory tract by fomites or aerosol transmission
  • epithelial cells are the first site for virus and there’s s host interaction
  • incited epithelial cells release cytokines that cause typical symptoms of viral: fever, aches etc
  • temperature differential between upper (cooler) and lower respiratory tract has consequences for pathogenesis- rhinovirus replicate preferentially in URT, differential basis for attenuated viral vaccines
  • age effect: infants and elderly have more severe infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which viruses cause rhinitis, pharyngitis and laryngitis?

A
Rhinovirus
Cornavirus
Parainfluenza virus
RSV
Influenza virus
Adenovirus 
Herpes simplex virus
EBV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which viruses cause tracheitis, bronchitis, bronchiolitis, bronchopneumonia?

A

Parainfluenza virus
RSV
Influenza virus
Adenovirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the pattern for an acute infection in respiratory tract?

A
  • acute infection with replication confined to respiratory mucosal surface
  • picornaviris(rhinovirus), coronavirus, paramyxovirus (parainfluenza and RSV), orthomyxovirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the pattern of persistent virus infection in respiratory tract?

A
  • persistent replication on respiratory mucosal surface

- EBV, Adenovirus, papilloma virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the pattern of systemic replication in respiratory tract?

A
  • dissemination after primary replication in respiratory tract
  • paramyxovirus (mumps, measles), herpesviruses (EBV, VZV, HHV6, CMV), rubella, picornaviris(polio)
  • other viruses: bunya, arena, parvo, pox, reo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the virology of coronavirus?

A
  • named for their crown of spikes
  • assRNA virus
  • most strains cause cold-like symptoms
  • rare new strains cause lethal respiratory diseases: SARS in 2003; MERS in 2013 (fruit bats -> camels -> humans)
16
Q

What does myxovirus name mean?

A

Myxo, Greek for mucus

These viruses bind to mucin protein on RBCs

17
Q

What does ortho mean?

A

Straight right proper

Influenza virus is the right one

18
Q

What does para mean?

A

Besides resembling

Measles virus is a bit like orthomyxovirus but not the same

19
Q

What are the differences between orthomyxovirdae and paramyxoviridae?

A

Ortho- genus influenza virus, types a b and c; nuclear replication; segmented -ssRNA genome*; enveloped

Para- 3 genera: paramyxovirus, (mumps, parainfluenza virus 1-4, Newcastle disease variant) morbillivirus (measles,rinderpest, canine distemper); pneumovirus (RSV); cytoplasmic replication; non segmented -ssRNA genome*; enveloped

20
Q

How does influenza virus cause disease?

A
  • dying epithelial cells
  • interferons
  • T cells
21
Q

What are some results of influenza infection?

A
  • secondary bacterial infection leading to pneumonia
  • primary viral pneumonia
  • CNS or muscle involvement
22
Q

What are some treatments for the flu?

A

Tamiflu(oseltamivir)- influenza a and b

Relenza (zanamivir)- influenza a and b

23
Q

How can we prevent the flu?

A

Flu zone- trivalent inactivated
Flu mist live attenuated vaccine
2014-2015 trivalent vaccines A/California/7/2009 (H1N1); A/Texas/50/2012 (H3N2) this has mutated now so the vaccine doesn’t help this strain but still vaccinating and just treat suspected cases of flu with antivirals; B/Yamagata lineage

24
Q

What is the virology of paramyxoviridae?

A
  • non-segmented negative sense ssRNA genome
  • little genetic variation
  • 3 subfamilies- pneumonoviriniae(RSV), paramyxovirinae(mumps and parainfluenza virus); morbillivirus(measles, canine distemper)
  • MMR vaccine for measles and mumps (and rubella)
25
Q

What is croup?

A

Laryngotracheobronchitis caused by parainfluenza virus and respiratory syncytial virus

  • peak in winter
  • starts like a cold in adults and infants
  • commonly treated at home with steam and humidifiers
  • complications include pneumonia and respiratory distress
26
Q

What are respiratory infections caused by adenovirus like?

A
  • icosahedral naked DNA virus
  • widespread in nature infecting birds, mammals and humans
  • isolated in 1953 from humans by investigators trying to establish cell lines from adenoidal tissue
  • 100 serotonergic, 47 can infect humans
  • most people have been infected with at least 1 type by age 15
  • adenovirus infections are very common but most are asymptomatic
  • most infections involve the respiratory or GI tract or the eye
27
Q

What are the diseases caused by adenovirus?

A
Febrile upper tract infection 
Pharyngoconjunctial fever
Acute disease
Pertussis like disease
Pneumonia
Acute hemorrhagic  cystitis
Epidemic keratoconjunctivitis 
Gastroenteritis
28
Q

What is the adenovirus mechsnism of disease?

A
  • transmitted by aerosol, close contact, fecal-oral, or fingers and ophthalmologist instruments
  • virus infects muco epithelial cells of respiratory and go tract, conjunctiva, cornea
  • virus persists in lymphoid tissue (tonsils, adenoids,Peyers patches)
  • antibody is essential for recovery from infection
29
Q

What is the epidemiology of Adenoviruses?

A

Transmission: respiratory droplets, fecal matter, fomites, close contact, poorly sanitized swimming pools
Distribution of virus: ubiquitous, no seasonal incidence
At risk or risk factors: children younger than 14, military recruits, swimming clubs
Vaccines- live attenuated vaccine serotypes 4 and 7 for the military