Medical Dictionary


noun Ehr·lich·ia \er-ˈlik-ē-ə\

Medical Definition of Ehrlichia

  1. :  a genus of gram-negative nonmotile bacteria that are transmitted chiefly by tick bites and are intracellular parasites of humans and animals infecting the cytoplasm especially of circulating white blood cells (such as monocytes and granulocytes) Certain members of the genus Ehrlichia (such as E. equi and E. phagocytophila) are now typically placed in the genus Anaplasma. —see ehrlichiosis

Biographical Note for ehrlichia


\ˈer-ˌliḵ\play ,


(1854–1915), German chemist and bacteriologist. Ehrlich is celebrated for his pioneering research in hematology, immunology, and chemotherapy. He held a series of research positions at several institutions, including Berlin's Charité Hospital, Robert Koch's Institute for Infectious Diseases, and Frankfurt's Royal Institute for Experimental Therapy. His contributions included the invention of a new staining technique for the tuberculosis bacillus discovered by Robert Koch. The technique proved to be vitally important for the microscopic diagnosis of tuberculosis. Ehrlich is also credited with the important discovery that oxygen consumption varies with different types of tissue and that these variations constitute a measure of the intensity of vital cell processes. Perhaps his greatest achievement was his investigation into the mechanisms of bacterial infection and immunity. He developed a method for measuring the effectiveness of sera that was adopted worldwide for the standardization of diphtheria serum. His recognition of the limitations of serum therapy led to his search for synthesized substances that can kill parasites or inhibit their growth without damaging the organism. His researches marked the birth of chemotherapy. His study of the spirochete (Treponema pallidum) that causes syphilis led to his discovery of salvarsan, the first effective treatment for syphilis. With Élie Metchnikoff, he was awarded the 1908 Nobel Prize for Physiology or Medicine.

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to cast off or become cast off

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