Adult onset diabetes can be caused by a chlamydia infection, which causes endothelial dysfunction, inflammation, and dysbiosis. Chronic chlamydia creates reduced immunity, and a favorable environment for secondary bacteria, viruses, and parasites. Intestinal parasites can cause mechanical obstruction in the pancreas and common bile duct. Chlamydia pathogens and parasites have been found inside tumors in the pancreas, gallbladder, and liver. (H-pylori is an intestinal pathogen known to cause of cancer, which has also been found in pancreatic cancer).
In mice, acute chlamydia was shown to trigger the development of diabetes, and to accelerate insulin resistance (worsening of diabetes). Acute infections with immortal pathogens can trigger chronic disease, and worsen existing chronic diseases, including adult onset diabetes. As chronic infection persists, pathogens spread to become co-morbid diseases.