A study has linked collective exposure to Chlamydia pneumonia and Herpes Simplex Viruses 1 and 2, as well as Helicobacter pylori, cytomegalovirus with an increased risk for stroke. The working theory is that these pathogens may linger after an acute infection and possibly contribute to a prolonged state of low grade infection. Low grade infection can cause inflammation which in turn can lead to strokes.
The study, published in the online edition of the Archives of Neurology, followed 1,625 adults in Manhattan. During the length of the study 67 people had a stroke. After risk factors, such as smoking, diabetes and family history, were taken into account, the researchers discovered that a significant number of stroke victims were positive for at least one of the pathogens. It was also noted that people with a history of multiple infections were 40% more likely to experience a stroke.
The lead author, Dr. Elkind, pointed out that the study did not prove a cause-and-effect relationship but, only an association, and that the evidence was circumstantial.