Toxoplasma gondii
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- Toxoplasma gondii
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Toxoplasma is a genus of coccidian protozoa (suborder Eimeriina, order Eucoccidiida) comprising intracellular parasites of many organs and tissues of birds and mammals, including humans. The only known complete hosts are cats and other Felidae, in which both asexual and sexual developmental cycles occur in the intestinal epithelium, culminating in the passage of oocysts in the feces. The intestinal stages do not occur in other hosts.
Toxoplasma gondii is an obligate intracellular species found in a wide range of hosts, including humans and other mammals and birds. The sexual cycle of the organism takes place in the intestinal epithelium of the cat, which is the definitive host. It exists in three forms: tachyzoite, tissue cysts (pseudocysts), and oocysts. Infection (toxoplasmosis) occurs chiefly by ingestion of oocytes shed in cat feces or by ingestion of cysts in raw or uncooked meat.