Color enhanced TEM of ultrathin sections of Corynebacterium diptheriae. In high iron medium, unusual branching is visible. Corynebacteria are rod-shaped, gram-positive and nonmotile. Though many of the species are pathogens in domestic animals, birds and plants, the most important is the secies C. diptheriae--the causative agent of diptheria in humans. The disease is characterized by the formation of a false membrane on any mucous surface and occasionally on the skin. In nasal diptheria, fever is a much more evident symptom. Adenitis is often severe, with serious discharge from the nostrals, which may be blood tinged. Myocarditids and late neuritis are commonly present. TEM Magnification = x21,500 at 70mm