Many medical scientists have proposed infectious pathogens cause chronic disease, or are associated with chronic disease, for decades. Some propose bacteria, viruses, parasites and fungus; and others specifically state chlamydia species, viruses such as EBV and coronavirus, parasites such as toxoplasmosis and Lyme disease, h-pylori, streptococcus, and others. Many note the impact of specific pathogens and co-pathogens, and the overall infectious burden, as accelerating or worsening chronic disease.
Chlamydia species are intracellular bacteria that can damage cell function and host other pathogens. Chlamydia can mix intracellularly with other pathogens inside the cell; viruses can become intracellular during the reproduction phase; h-pylori attacks epithelium and burrows into collagen causing atrophy and creating ports for other pathogens to enter; and parasites can start in the intestine and migrate to other abdominal organs and the brain. Immortal pathogens, alone or in combination, can evolve into chronic disease over time. The type of chronic disease may depend on the type of pathogen, the mode of transmission and attack, the infectious burden, and the duration of infection. The more immortal pathogens a person acquires, across the placenta and during life, the greater the likelihood of developing a chronic disease over time.