Respiratory viruses Flashcards
What precaution is taken for droplet infections?
- Surgical mask
What viruses cause common cold?
- Coronavirus
- Rhinovirus
- RSV
- Adenovirus
What are the 3 types of influenza viruses?
- A: mammalian and avian species
- B & C: humans
Which influenza causes pandemics?
- Influenza A
What is the genome of the influenza virus?
- 8 segments
- Antigens: haemagglutinin (HA) and neuraminidase (NA)
What is antigenic drift?
- Minor antigen changes
- Transcription errors by DNA polymerase
- YEARLY EPIDEMICS
What is antigenic shift?
- Major antigenic change
- Genetic re-assortment when two viruses attack host at same time
- PANDEMIC
What is the pathogenesis of influenza?
- Droplet enters
- HA binds to receptors on host
- NA cleaves sialic acid to allow virus to enter
- Virus causes lymphocyte destruction
- Loss of cilia + inflammation of trachea and bronchi
- Droplet spread
What are consequences of viral infection?
- Influenza** pneumonia**
- Bacterial superinfection, leading to pneumonia
- Myocarditis, encephalitis
- Reye’s syndrome
- Death
What treatment is given for influenza?
- Antipyretics
- Analgesia
- Antivirals (Oseltamivir)
Who is the influenza vaccine recommended for?
Yearly for:
- healthcare workers
- young children
- at risk groups: chronic illness, immunosuppression, pregnant women, obese, older people
Who is RSV most common in?
- Young children: LRTI
What is RSV bronchiolitis?
- Inflammation of bronchioles
- first most common cause of childhood hospitalisation
- tachypnoea, wheeze
- apnoea
- cyanosis
- lower lung hyperinflation
What is the treatment for RSV?
- No effective vaccine
- Antiviral: ribavirin
- Droplet precautions
What is parainfluenza and what does it cause?
- Four serotypes (4a + 4b)
- Croup (laryngotracheobronchitis)
- second most common cause of childhood hospitalisation
What is adenovirus and what does it cause?
- 50 serotypes
- Causes RTI, diarrhoea and conjunctivitis
What test is done for viruses?
- PCR
serology and culture not done
What is avian influenza?
- Disease of birds caused by influenza A
- Humans get infection from infected poultry
new viral infection
What is MERS-CoV?
- Middle eastern respiratory corona virus
- Camels major reservoir host
- majority in saudi arabia, first case in UAE
What is the structure of SARS-Cov-2
- 4 main structural proteins: spike, envelope, nucleocapsid, membrane
- 16 non-structural proteins, 5-8 accessory proteins
- Binds to ACE2 receptor in lungs
How is COVID spread?
- Primarily droplet
- Aerosol, fomite
How many COVID infections are asymptomatic?
- 80%
- 15% moderate
- 5% severe
How is COVID diagnosed?
- PCR
- Antigen testing
