viral infections of lower respiratory respiratory 2 Flashcards
(33 cards)
What is the most common cause of LRTIs in infants and young children?
Respiratory Syncytial Virus (RSV).
What are the antigenic subtypes of RSV?
Type A (more frequent) and Type B.
What clinical features are associated with RSV bronchiolitis?
Fever, respiratory distress, wheezing, crackles, atelectasis, hypoxia.
What is the peak season for RSV?
Winter.
How does RSV cause disease?
G-protein mediates attachment, F-protein mediates fusion; syncytia formation and cell injury.
What complications can RSV cause?
Interstitial pneumonia, asthma/COPD exacerbation, bacterial superinfections.
What is the recommended prevention for RSV?
Vaccination, hygiene, antivirals for severe cases.
What virus is similar in clinical and epidemiologic features to RSV?
Human Metapneumovirus (HMPV).
How is HMPV diagnosed?
RT-PCR is required to differentiate it from RSV.
What family does HMPV belong to?
Paramyxoviridae.
What are the three clinical phases of Hantavirus Pulmonary Syndrome (HPS)?
Prodromal, cardiopulmonary, convalescent.
What are the symptoms during the prodromal phase of HPS?
Fever, headache, myalgia, vomiting, diarrhea.
What is the cause of pulmonary edema in HPS?
Capillary leak from immune-mediated endothelial damage.
What is the most common Hantavirus strain in the US?
Sin Nombre virus.
How is Hantavirus transmitted?
Aerosolized rodent excreta, direct contact, ingestion of contaminated food.
What is the treatment for Hantavirus?
Supportive care. No specific antiviral treatment.
How is Hantavirus diagnosed?
RT-PCR for viral RNA; ELISA for IgM and IgG.
What is the genome structure of the influenza virus?
Enveloped, segmented (8 segments), negative sense RNA.
What are the main glycoproteins of Influenza and their functions?
HA binds sialic acid (attachment), NA cleaves sialic acid (virion release).
What causes antigenic drift in influenza?
Accumulation of point mutations in HA and NA leading to minor changes.
What causes antigenic shift in influenza?
Reassortment of RNA segments between different strains, leading to major changes.
What type of influenza is zoonotic and can cause pandemics?
Influenza type A.
What are complications of influenza?
Bacterial pneumonia, sinusitis, otitis media, ARDS, encephalitis, Guillain-Barré.
What vaccines are available for influenza?
Live attenuated (nasal spray) and killed inactivated (injection).
