Appendicitis is an inflammation of the appendix, which is a small pouch attached to the large intestine. It is caused by a blockage, usually due to infection. Viral infections do not cause appendicitis directly, but can weaken the immune system, making it more likely for bacteria to travel to the appendix and cause an infection. Bacteria such as E. coli, Salmonella, and Shigella can then lead to inflammation and appendicitis. In some cases, a viral infection can cause a blockage in the appendix, leading to appendicitis. Therefore, while viruses are not the direct cause of appendicitis, they can contribute to its development.