Some science behind the scenes

Respiratory infections

See also antivirals and antibiotics in the activity sections.

Upper respiratory tract infections (URI or URTI) are illnesses caused by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx or larynx. This commonly includes: tonsillitis, rhinitis, pharyngitis, laryngitis, sinusitis, and the common cold. Pain and pressure of the ear caused by a middle ear infection (Otitis media) and the reddening of the eye caused by viral Conjunctivitis are often associated with upper respiratory infections.

Over 200 different viruses have been isolated in patients with URIs. The most common virus is called the rhinovirus. Other viruses include the coronavirus, parainfluenza virus, adenovirus, enterovirus, and respiratory syncytial virus. Up to 15% of acute pharyngitis cases may be caused by bacteria, commonly Group A streptococcus in Streptococcal pharyngitis ("Strep Throat").

Symptoms of URI's commonly include cough, sore throat, runny nose, nasal congestion, headache, low grade fever, facial pressure and sneezing. Onset of symptoms usually begins 1–3 days after exposure. The illness usually lasts 7–10 days.