Respiratory viruses Flashcards
What are the symptoms of ‘seasonal flu’?
STOP
Sore throat
Temperature
Onset (sudden)
Pains and muscle aches
What kind of virus is the influenza virus?
Orthomyxoviridae
Types A, B, C
Which feature of influenza leads to its epidemic nature?
Variation in its two envelope glycoprotein antigens
H (hemagglutinin) binds to cell
N (neuraminidase) protein cleaves new virus to allow spread
Discuss the treatment of influenza
M2 inhibitors
- only influenza A
Neuraminidase inhibitors
- influenza A and B
Discuss the difference in antigenic drift vs shift
Drift
- minor change, same subtype, cause by point mutations, causes epidemics
Shift
- major change, new subtype, cause by gene segment exchange, causes pandemics
Name M2 inhibitors
Amantidine
Rimantidine
Name neuraminidase inhibitors
Oseltamivir
Zanamivir
Which influenza vaccine is more effective in children?
Live attenuated
Name complications of influenza
Pneumonia
ARDS
Organ failure
MI
Stroke
Heart/brain inflammation
What features of influenza leads to enhance susceptibility to s.pneumo?
- Destruction of respiratory epithelium and exposure of BM
- Up-regulation of molecules used by bacteria as receptors
- Impaired function of immunological cells
Differentiate the clinical features of influenza vs RSV
RSV has more
- nasal congestion
- wheezing
- sputum production
and less
- fever
- myalgias
- GIT symptoms
Discuss treatment of RSV infection
Generally supportive
In transplant patients:
Ribavirin
IVIG
Palivizumab (monoclonal Ab)
Discuss immunisation strategies for RSV
- Recombinant vector based vaccines
- use modified replication defective virus
- assoc with thromboembolism - Nucleic acid based vaccines
- based on introducing mRNA encoding RSV antigens - Protein based vaccines
- whole-inactivated virus
- mostly for older adults and mothers - Live attenuated vaccines
- mimic natural infection
- do not appear to cause vaccine enhanced disease - Monoclonal antibodies
- passive immunisation
Which family does human metapneumovirus belong to?
Paramyxovirus
Discuss features of human metapneumovirus
Common in children
Closely related to RSV and similar presentation although less severe
Droplet tranmission
Winter outbreaks
PCR most sensitive
Supportive treatment
Discuss the features of measles
Airborne transmission
Highly contagious
Incubation 9-14d
Multilobar reticulonodular infiltrate on CXR
Secondary bacterial infections common
Name complications of measles infection
Hepatitis
Encephalitis
Keratitis
Mesenteric adenitis
Severe diarrhoea
Discuss the clinical presentation of measles
Prodrome 2-8d
- fever, anorexia, cough, coryza, conjunctivitis, koplik spots
Maculopapular erythematous rash from face to extremities
What is the incubation period of VZV?
2 weeks
Discuss diagnosis of VZV
Clinical (rash + pneumonia)
Tzank smear (lesion scrapings)
Direct immunofluorescence
BAL PCR
Discuss treatment of VZV pneumonia
IV acyclovir for 5-7d
What was the intermediate host of SARS-CoV-1?
Civet cat
What was the intermediate host of MERS-CoV?
Camel
What was the intermediate host of SARS-CoV-2?
Pangolin
What were the 4 major structural proteins targeted for covid-19 vaccine?
Spike protein
Membrane protein
Envelope protein
Nucleocapsid protein
