Immune system or the use of immunosuppressive medication. In contrast, autoimmunity results from a hyperactive immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimoto's thyroiditis, rheumatoid arthritis, diabetes mellitus type 1, and systemic lupus erythematosus. Immunology covers the study of all aspects of the immune system. Immunology is a science that examines the structure and function of the immune system. It originates from medicine and early studies on the causes of immunity to disease. The earliest known reference to immunity was during the plague of Athens in 430 BC. Thucydides noted that people who had
Cat-scratch disease Warthin-Starry silver stain was used to discover a Gram-negative bacillus which was named "Afipia felis" in 1991 after it was successfully cultured and isolated. The causative organism of CSD was originally believed to be "Afipia felis", but this was disproved by immunological studies in the 1990s demonstrating that cat-scratch fever patients developed antibodies to two other organisms, "B. henselae" (originally known as "Rochalimea henselae" before the genera "Bartonella" and "Rochalimea" were combined) and "B. clarridgeiae", which is a rod-shaped Gram-negative bacterium. Cat-scratch disease Cat-scratch disease (CSD) is an infectious disease that results from a scratch or bite of a cat.