Some studies suggest that people with chronic infection are more likely to have common types of cardiovascular disease (coronary heart disease and strokes) than people without chronic infection. However, these studies have not been able to sort out whether chronic infection occurred before or after the disease developed. Some of the bacteria and viruses (“germs”) that researchers have found in people with coronary disease include Chlamydia pneumoniae, Helicobacter pylori, herpes simplex virus, and cytomegalovirus.