When a cat's lungs are infected, they will initially have symptoms such as difficulty breathing, fever, runny nose, and lack of energy. They are usually caused by bacterial infection. You should take the cat to the pet hospital for examination and treatment in time. Pay attention to keeping the home environment clean, clean the cat's living area regularly, and change the water, cat litter, and cat food frequently to prevent it from deteriorating over time and causing odor, which will affect the cat's health.