What characterizes an upper respiratory infection (URI)?

An upper respiratory infection (URI) is defined as an infection that primarily affects the upper sections of the respiratory tract, specifically the nasal cavity, pharynx, and larynx. This region is responsible for filtering, warming, and humidifying the air we breathe before it enters the lower respiratory tract. URIs are commonly caused by viruses, such as the common cold or influenza, and can lead to symptoms like a sore throat, nasal congestion, and cough.

The focus on the upper respiratory tract distinguishes URIs from lower respiratory infections, which involve the lungs and structures such as the trachea and bronchi. By understanding that URIs specifically target the nasal passages, throat, and voice box, one can better identify and manage the symptoms and complications associated with these infections.