Post-viral syndromes refer to a range of symptoms that persist after the initial infection of a virus has resolved. These symptoms can include fatigue, muscle pain, joint pain, and cognitive difficulties, often affecting daily activities. Common examples of viruses associated with these syndromes include COVID-19, influenza, and Epstein-Barr virus. The exact cause of post-viral syndromes is not fully understood, but they may involve immune system responses or lingering viral particles in the body. Diagnosis typically involves ruling out other conditions, and treatment focuses on managing symptoms and improving quality of life.