An anemia which develops as a result of long–term infection or disease is termed as anemia of chronic infection. Causes Certain chronic infections and diseases cause several changes in the blood production (hematopoietic) system. These include a slightly shortened red blood cell life span, decreases in the amount of iron that is available in the fluid portions of blood, and decreases in the activity of the bone marrow. In the presence of these three effects a low to moderate grade anemia develops. The symptoms of the anemia often go unnoticed in the face of the primary disease. Conditions associated with the anemia of infection and chronic diseases include such diverse diseases as chronic bacterial endocarditis, osteomyelitis, juvenile rheumatoid arthritis, rheumatic fever, Crohn’s disease, and ulcerative colitis. Chronic renal failure may produce a similar anemia because it causes reduced levels of erythropoietin, the hormone which stimulates the production of red blood cells in the bone marrow.