Viral Infection Of The Upper Respiratory Tract Flashcards
What are the viral causes of the common cold?
Rhinovirus- 30-50% Coronavirus- 10-15% Influenza virus- 5-15% RSV- 5% Parainfluenza 5% Adenovirus <5% Metapneumovirus unknown Unknown 20-30%
What is the impact of viral respiratory infections in the US?
- 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
What are the frequent symptoms of a rhinovirus infection
Most-common cold
Occasional-exacerbation of chronic bronchitis and asthma
Infrequent- pneumonia in children
What are the frequent symptoms of a cornavirus infection?
Most- common cold
Occasional- exacerbation of chronic bronchitis and asthma
Infrequent- pneumonia and bronchioles is
What are the frequent symptoms of human respiratory syncytial virus infection?
Most- pneumonia and bronchiolitis in young children
Occasional- common cold in adults
Infrequent- pneumonia in elderly and immunosuppressed
What are the most frequent symptoms for parainfluenza virus infection?
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
What are the most frequent symptoms for adenovirus infection?
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
What are the frequent symptoms of influenza a virus?
Most-influenza
Occasional-pneumonia and excess mortality in high risk patients
Infrequent- pneumonia in healthy individuals
What are the symptoms of a influenza b infection?
Most- influenza
Occasional- rhinitis or pharyngitis alone
Infrequent- pneumonia
What are the features of a respiratory infection?
- 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
Which viruses cause rhinitis, pharyngitis and laryngitis?
Rhinovirus Cornavirus Parainfluenza virus RSV Influenza virus Adenovirus Herpes simplex virus EBV
Which viruses cause tracheitis, bronchitis, bronchiolitis, bronchopneumonia?
Parainfluenza virus
RSV
Influenza virus
Adenovirus
What is the pattern for an acute infection in respiratory tract?
- acute infection with replication confined to respiratory mucosal surface
- picornaviris(rhinovirus), coronavirus, paramyxovirus (parainfluenza and RSV), orthomyxovirus
What is the pattern of persistent virus infection in respiratory tract?
- persistent replication on respiratory mucosal surface
- EBV, Adenovirus, papilloma virus
What is the pattern of systemic replication in respiratory tract?
- 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