The immune system plays an important role in disease causes and prevention. Infectious diseases are often as much about how particular cats respond to infection as well as the cause of infection itself. What vaccinations to give and their timing is a rapidly evolving area that we are paying close attention to. Diseases like asthma or inflammatory bowel disease are associated with an over-response of the immune system. The medications used for the treatment of problems such as cancers can have effects on the immune system.