Medical research is plagued by reports of “associations”.  Research studies often look for a single pathogen in chronic disease; and fail to consider multiple pathogens can work together to cause chronic disease, or that different pathogens can cause the same chronic disease, which leads to reports of an “association” rather than a cause. A doctor in medical practice may not be allowed to treat a patient based on reports of an “association” between a pathogen and a chronic disease. Causes of chronic disease can only be found when researchers and physicians take a broader view, have the courage to theorize and report a cause, and researchers and physicians begin to diagnose immortal bacteria and parasites and observe the results of treatment.