Acute Respiratory Infections Flashcards
What are the 2 more serious Influenza infections?
Influenza A and B
How is influenza transmitted?
It is an airborne virus and is transmitted in droplets - coughing, sneezing and talking
How long can influenza remain on surfaces?
24 hours
What is the average incubation period for an influenza infection?
2 days (1-4)
What are the 2 surface antigen classes that are on flu virus surfaces?
H and N classes
How are flu mutations classed?
According to their surface antigens e.g. H1N1 (swine flu) H7N9 etc.
Define ‘Antigenic drift’
Gradual accumulation of mutations that change the surface antigens and make the virus less susceptible to the antibodies produced during previous infections.
Define ‘Antigenic shift’
Two or more strains combine to form a new subtype with surface antigens that humans have not encountered previously (completely new surface antigens)
What are the symptoms of an influenza infection?
- Fever
- Cough
- Sore throat
- Myalgias
- Frontal/retro-orbital headache
- Fatigue
- Conjunctivitis
How long should it take for someone to get over uncomplicated influenza?
2-5 days
Define ‘Uncomplicated influenza’
Influenza with fever, coryza, generalised symptoms and GI symptoms.
Define ‘complicated influenza’
Influenza requiring hospital admission and/or with symptoms of LRTI (hypoxaemia, dyspnoea, lung infiltrates), CNS involvement and/or significant exacerbation of an underlying medical condition.
What are the risk factors for complicated influenza?
- Neuro, hepatic, renal, pulmonary and chronic cardiac disease
- DM
- Immunosuppression
- > 65
- Pregnancy (up to 2 weeks post partum)
- Morbidly obese (BMI >40)
What are the 4 complications of influenza?
- Primary viral pneumonia
- Secondary bacterial pneumonia
- Myositis and rhabdomyolysis
- CNS complications
What is MERS-CoV?
Middle-Eastern respiratory syndrome related coronavirus