Major impediments to understanding infectious causes of chronic disease are the lack of a more detailed medical history of chronic diseases in household members; a history of animal contact, particularly with sick animals; and lack of available broad-based blood testing for bacterial, viral and parasitic pathogens. Blood testing asks, “Does the patient have this pathogen?”, rather than “what pathogens are in the patients’ blood?”. Veterinarians know the risk of transmission of many animal pathogens to humans; and wrote about the potential danger of transmission of Bartonella to humans, in 2011, recognizing humans and animals get the same diseases from the same pathogens and advising greater caution concerning animal pathogens.
Chlamydia antibody blood testing is done for only 3 of the major chlamydia pathogens, out of 15 known species and potentially more than 300 suspected species. Testing for lesser known chlamydia species, and for viral pathogens, must be ordered one at a time, causing undue expense and the potential for missing the root infectious cause. Some labs stopped offering blood testing for H-pylori and only offer a stool test, which can miss the diagnosis of H-pylori in other parts of the body, such as organs along the gastrointestinal tract and the eye. Parasites may be suggested by high levels of monocytes in the blood; but diagnosis by direct inspection of stool can be unreliable and does not diagnose parasites that migrated to other parts of the body, such as internal organs, the eye, and the brain.
In medical practice, a doctor must understand the role of pathogens in chronic disease, recognize signs of infectious pathogens, guess at the pathogens, and get permission for “expensive” blood testing from superiors and insurance to perform blood testing for a specific pathogen. High throughput sequencing reveals hundreds of pathogens in a blood sample, could allow discovery root infectious causes of chronic disease, and could lead new medical breakthroughs in research and originating from experience in medical practice. We need broad-based diagnostic testing of blood, such as high-throughput sequencing, to be routinely available in research and practice.