an organism that can reproduce itself in a host
A chronic disease is one that persists over a long time, and may have cumulative effects on the body. Since Ebola (also known as Hemorrhagic Fever) is a relatively short acting, frequently terminal disease, it is more likely to be termed "acute" rather than "chronic".
GBS is termed a syndrome rather than a disease because there is no conclusive evidence to support the possibility that a specific disease-causing agent such as a bacteria or a virus is the direct cause of the malady.
4 autoimmune disease
Pigeons feces carry fungi like histoplasmosis and cryptococcus neoformans as well as other infectious bacterial disease chlamydia psittici. Most of these infections are what are termed as "opportunistic infections", meaning they usually do not cause problems for people unless they are immune compromised (luekemias, chemotherapy and AIDS). Hope that answers your question... SS Medical Student TAMU
Their growth seems to be dependent upon continuous stimulation of the immune system by an infectious agent, such as H. pylori, or some other entity, termed an antigen, that the body recognizes as foreign.