To investigate the presence of infectious agents in human atherosclerotic arterial tissues. Atherosclerotic plaques were removed from 128 patients undergoing carotid endarterectomy or other bypass procedures for occlusive disease, and from twenty normal arterial wall samples, obtained from transplant donors with no history of diabetes, hypertension, smoking, or hyperlipidemia. Using the polymerase chain reaction (PCR) or reverse transcription-PCR, these samples were analyzed for the presence of Chlamydia pneumoniae, cytomegalovirus, enterovirus, adenovirus, herpes simplex viruses types 1 and 2, and Epstein-Barr virus. The amplicons were then sequenced, and phylogenetic analyses were performed. Enteroviral RNA was found in 22 of 128 atherosclerotic vascular lesions $(17.2\%),$ and C. pneumoniae and cytomegalovirus were each found in 2 samples $(1.6\%).$ In contrast, adenovirus, herpes simplex viruses, and Epstein-Barr virus were not identified in any of the atherosclerotic samples. Enterovirus was detected in 6/24 $(25.0\%)$ aortas, 7/33 $(21.2\%)$ carotid arteries, 6/40 $(15.0\%)$ femoral arteries, and 3/31 $(9.7\%)$ radial arteries of patients with chronic renal failure. There were no infectious agents detected in any of the control specimens. Using phylogenetic analysis, the enterovirus isolates were clustered into 3 groups, arranged as echovirus 9 and coxsackieviruses Bl and B3. Enteroviral RNA was detected in $17.2\%$ of atherosclerotic plaques, but was not observed in any of the control specimens. This suggests a connection between enteroviral infection and atherosclerosis. These findings differ from those of other studies, which found more frequent incidence of C. pneumoniae and cytomegalovirus infection in atherosclerotic plaques.
