Anyone who has ever had a cold knows about acute respiratory infections (URIs). An acute URI is a contagious infection of your upper respiratory tract. Your upper respiratory tract includes the nose, throat, pharynx, larynx, and bronchi. Without a doubt, the common cold is the most well-known URI. Other types of URIs include sinusitis, pharyngitis, epiglottitis, and tracheobronchitis. Influenza, on the other hand, isn’t an URI because it’s a systemic illness.