Keywords: Yersinia pestis.jpg Scanning electron micrograph depicting a mass of Yersinia pestis bacteria the cause of bubonic plague in the foregut of the flea vector Credit Rocky Mountain Laboratories NIAID NIH http //www3 niaid nih gov/biodefense/Public/Images htm Text of cropped caption DD2017 10 0kV X20 0K 1 50µm PD-USGov Yersinia pestis |