An<unk>  <unk>  is an illness caused by an acute<unk> , which involves the<unk>  respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most<unk> s are viral in nature, and in other instances, the cause is bacterial.<unk> s can also be fungal or helminthic in origin, but these are less common. In 2015, 17.2 billion cases of<unk> s are estimated to have occurred. As of 2014, they caused about 3,000 deaths, down from 4,000 in 1990.
Upper respiratory tract infection
Carbon monoxide poisoning
Lower respiratory tract infection
Respiratory tract infection
Post-viral cough
Allergic rhinitis
Croup
Bronchorrhea