Viral Upper Respiratory Tract Infections Flashcards
what are the three most common causes of a cold?
rhinovirus, coronavirus and influenza virus
how are viral respiratory infections transmitted? where are the first site of virus host interaction?
fomites or aerosol transmission
epithelial cells
what is the most common presentation of rhinovirus? occasional presentation? rare presentation?
common cold
exacerbation of chronic bronchitis and asthma
pneumonia in children
what is the most common presentation of coronavirus? occasional presentation? rare presentation?
common cold
exacerbation of chronic bronchitis and asthma
pneumonia and bronchiolitis
what is the most common presentation of human respiratory syncytial virus? occasional presentation? rare presentation?
pneumonia and bronchiolitis in young children
common cold in adults
pneumonia in elderly and immunosuppressed
what is the most common presentation of parainfluenza viruses? occasional presentation? rare presentation?
croup and lower respiratory tract disease in young children
pharyngitis and common cold
tracheobronchitis in adults, lower respiratory tract disease in imunosuppressed
what is the most common presentation of adenovirus? occasional presentation? rare presentation?
common cold and pharyngitis in children
outbreaks of acute respiratory disease in military recruits
pneumonia in children, lower respiratory tract and disseminated disease in immunocompromised
what is the most common presentation of influenza A viruses? occasional presentation? rare presentation?
influenza
pneumonia and excess mortality in high risk patients
pneumonia in healthy individuals
what is the most common presentation of influenza B viruses? occasional presentation? rare presentation?
influenza
rhinitis or pharyngitis alone
pneumonia
what causes the typical symptoms of viral disease? what are they?
infected epithelial cells release cytokines
fever, aches etc
what makes viruses specific to the upper respiratory tract? what else utilizes this difference?
temperature requirements of the virus to replicate
basis for attenuated viral vaccines
what is the age effect on viruses?
infants and elderly have more severe respiratory infections
what are the three patterns of virus replication in the respiratory tract?
acute- confined to repiratory mucosal surface
persistent- continued replication on respiratory mucosal surface
systemic- dissemination after primary replication in respiratory tract
which five viruses have an acute pattern of replication?
picornavirus (rhinovirus), coronavirus, paramyxovirus (parainfluenza and respiratory cyncytial virus) and orthomyxovirus (influenza)
which three virus have a persistent pattern of replication?
EBV, adenovirus and papillomavirus
which five viruses have a systemic pattern of replication?
paramyxovirus (mumps and measles), herpesviruses, rubella, picornavirus (polio) and others
what do coronaviruses look like? what type of genome does it contain?
enveloped viruses with spikes around it
- ssRNA virus
what types of coronavirus have shown to be lethal?
SARS and MERS
what constitutes a myxovirus?
they bind to mucin protein on RBC
what viruses are part of the group orthomyxoviridae?
influenza viruses A, B and C
what are the ree genera of paramyxoviridae? which important viruses do they contain?
paramyxovirus- mumps and parainfluenza
morbillivirus- measles
pneumovirus- respiratory syncytial virus
where do orthomyxoviruses and paramyxoviruses replicate? what is their genome? what is their structure?
ortho- nuclear, segmented - ssRNA and enveloped
para- cytoplasmic, nonsegmented - ssRNA and enveloped
what are the major contributorsto the pathogenesis of influenza syndrome?
T cell responses, interferon induction and desquamation of mucus secreting and ciliated cells
what are the symptoms of influenza syndrome?
high fever, headache, tiredness, cough, sore throat, runny/stuffy nose, body aches, diarrhea and vomitiong
what are less frequent outcomes of influenza?
secondary bacterial infection that could turn into a pneumonia, primary viral pneumonia and CNS or muscle involvement
what is the immune response to influenza?
interferon induction, T cell responses and antibody production
what are the treatments and prevention for the flu?
treatment- tamiflu and relenza for Influenza A and B
vaccines- fluzone (trivalent inactivated) and flumist (live attenuated vaccine)
what are the 2014 trivalent vaccines?
H1N1, H3N2 and B/yamagata lineage
what is croup? when is the peak incidence?
laryngotracheobronchitis
peak incidence in winter
what are the symptoms of croup? what are the complications?
starts like a cold in adults and infants. infants may develop a distinct barking cough
complications include pneumonia and respiratory distress
how is croup usually treated?
at home with steam and humidifiers
describe the morphology of adenovirus. who does it affect?
icosahedral naked DNA virus
affects birds, mammals and humans
what is the most common consequence of adenovirus infection?
most are asymptomatic. others involve the respiratory tract, GI tract or the eye
describe the mechanism of adenovirus infection and what immune response is effective against it
infects mucoepithelial cells and persists in lymphoid tissues
antibody is needed for recovery
how is adenovirus transmitted? what vaccines are available?
respiratory droplets, fomites, fecal matter, close contact and poorly sanitized swimming pools
live attenuated vaccines for serotypes 4 and 7 given to military members
