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Description:This photomicrograph depicts numerous Gram-positive asporogenous, rod-shaped, Corynebacterium diphtheriae bacteria.

The incubation period is 2-5 days (range 1-10 days), and the onset of symptoms is gradual. Early symptoms of respiratory diphtheria include malaise, sore throat, difficulty in swallowing, loss of appetite, and a mild fever (rarely >101° F). If the larynx is involved, the affected person may become hoarse. Within 2–3 days, an adherent, gray membrane forms over the mucous membrane of the tonsils, pharynx, or both. Attempts to remove the membrane cause bleeding. In severe cases of respiratory diphtheria, cervical lymphadenopathy and soft tissue swelling in the neck give rise to a “bull-neck” appearance. Extensive membrane formation may result in life-threatening or fatal airway obstruction.
Diphtheria toxin can cause serious systemic complications including myocarditis and neuropathies, if it is absorbed from the site of infection. Cutaneous and nasal diphtheria are localized infections that are rarely associated with systemic toxicity. The case-fatality rate of respiratory diphtheria is 5%-10%.

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Content Providers(s):CDC/ Graham Heid
Creation Date:1965
Photo Credit:
Links:CDC - National Center for Immunization and Respiratory Diseases: Division of Bacterial Diseases: Diphtheria
CDC Organization
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Copyright Restrictions:None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.