What Is an Upper Respiratory Infection?
1. What Is a URI?
Both viruses and bacteria can cause an upper respiratory infection. However, the most frequent culprit is a virus. There are several types responsible for creating the symptoms seen in a URI. Most common among them are rhinovirus, influenza virus, adenovirus and enterovirus.
Bacterial upper respiratory infections are less common, but they can lead to serious illness. The bacteria most often associated with URIs are beta-hemolytic streptococci Groups A and C.
