Belongs to orthomyxovirus group and exists in two main forms, A and B (e.g. influenza A)
Human immunity develops against the haemagglutinin antigen and the neuraminidase antigen on the viral surface (e.g. H1N1 = swine flu)
- Incubation period is usually 1-3 days.
- Illness starts with fever, shivering and generalised aching of the limbs.
- Associated severe headache, soreness of throat and persistent dry cough that can last several weeks.
- Secondary bacterial infection, particularly Strep.pneumoniae and H.influenzae (causative agents of CAP).
- Bed rest and paracetamol.
- Antibiotics in people with chronic bronchitis, heart or renal disease (‘at risk’ pts).