What is an upper respiratory infection (URI) primarily caused by?

An upper respiratory infection (URI) is primarily caused by bacteria or viruses. This encompasses a range of infections that affect the nasal passages, sinuses, throat, and larynx. The common cold, influenza, and sinusitis are all examples of URIs, which are mainly caused by viral pathogens such as rhinoviruses, influenza viruses, and coronaviruses, although bacterial infections can also contribute to URIs in certain situations.

The significant point is that the majority of upper respiratory infections are viral in origin, which is why people often experience symptoms during cold and flu seasons when these viruses are more prevalent. Bacterial URIs may occur subsequent to a viral infection when the immune system is already compromised or when bacteria that typically do not cause illness take advantage of the weakened state of the respiratory tract.

While genetic factors can play a role in a person’s susceptibility to infections, and environmental pollutants can aggravate respiratory conditions, they are not the primary causative agents of URIs. Excessive physical activity does not directly cause URIs, although it may influence overall health and immunity. Therefore, the most accurate choice to describe the primary cause of upper respiratory infections is bacteria or viruses.