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glossary:parasite [2008/05/15 16:51]
Pat O'Connor
glossary:parasite [2012/10/16 14:40] (current)
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 + An [[organism]] that lives in or on and takes its nourishment from another organism. A parasite cannot live independently. ​
 +Parasitic [[disease]]s include [[infection]]s by [[protozoa]],​ helminths, and arthropods: ​
 +**[[Protozoa]]** -- Malaria is caused by plasmodium, a protozoa, a single-[[cell]] [[organism]] that can only divide within its host organism.
 +**Helminths** -- Schistosomiasis,​ another set of very important parasitic diseases, is caused by a helminth (a worm).
 +**Arthropods** -- The arthropods include insects and arachnids (spiders, etc.), a number of which can act as vectors (carriers) of parasitic diseases.
 +The term "​parasite"​ came from the Greek "​parasitos"​ (para-, along side of + sitos, food) meaning "​eating at the side of, as at the same table."​ The sense of the term later changed to that of a poor friend or relative who lived at the expense of another. Not until the 18th century did "​parasite"​ come into English as a biologic term. 
 +The study of parasites is parasitology. ​
 +A parasite that lives or feeds on the outer surface of the host's body, such as a louse, tick, or leech, is called an **ectoparasite**. Ectoparasites do not usually cause [[disease]] themselves although they are frequently a vector of disease, as in the case of ticks, which can transmit the organisms that cause such diseases as Rocky Mountain spotted fever and Lyme disease.  ​
 +A parasite that lives inside the body of its host is called an **endoparasite**. Endoparasites include organisms such as tapeworms, hookworms, and trypanosomes that live within the host's organs or tissues, as well as organisms such as sporozoans that invade the host's cells
glossary/parasite.txt ยท Last modified: 2012/10/16 14:40 (external edit)