What is Caused by a virus and usually follows an upper respiratory infection?

A common condition caused by a virus that often follows an upper respiratory infection is acute bronchitis. This inflammation of the bronchial tubes can develop after a cold or flu, leading to symptoms like coughing, mucus production, and wheezing. Most cases are viral and resolve on their own, but symptoms can linger for weeks. Rest, hydration, and over-the-counter medications can help alleviate discomfort.