Viruses commonly implicated:
(1) rhinovirus
(2) respiratory syncytial virus (RSV)
(3) adenovirus
(4) coxsackie virus
(5) influenza
(6) parainfluenza
(7) human metapneumovirus
(8) human Boca virus
Risk factors for a viral respiratory infection include:
(1) several small children in the home
(2) outbreak in the community
(3) lack of protective antibodies (either naturally acquired or from vaccination)
(4) immune defects in the host (impaired T cell response, other)
Triggers for an asthma exacerbation in a patient with a viral respiratory infection:
(1) inhalation of an allergen
(2) air pollution, smoke or dust
(3) host response to the viral infection (inflammatory response, release of interferons, etc)
