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''Ascaris'' is a genus of parasitic nematode worms known as the "small intestinal roundworms", which is a type of helminth. One species, ''Ascaris lumbricoides'', affects humans and causes the disease ascariasis. Another species, ''Ascaris suum'', typically infects pigs. ''Parascaris equorum'', the equine roundworm, is also commonly called an "Ascarid". Their eggs are deposited in feces and soil. Plants with the eggs on them infect any organism that consumes them.〔(【引用サイトリンク】url=http://www.cdc.gov/parasites/ascariasis/ )〕 ''A. lumbricoides'' is the largest intestinal roundworm and is the most common helminth infection of humans worldwide. Infestation can cause morbidity by compromising nutritional status,〔Hall, A., G. Hewitt, V. Tuffrey and N. de Silva (2008). A review and meta-analysis of the impact of intestinal worms on child growth and nutrition. Maternal and Child Nutrition, 4 (Suppl 1): 118-236〕 affecting cognitive processes, inducing tissue reactions such as granuloma to larval stages, and by causing intestinal obstruction, which can be fatal. ==Morphology== * Adult: cylindrical shape, creamy white or pinkish in color * Male: average 15–30 cm and is more slender than female * Female: average 20–35 cm in length The body is long, cylindrical, fusiform (pointed at both the ends), body wall is composed of cuticle, epidermis and musculature. Presence of a false body pseudocoelom not lined by epithelium. Digestive system is complete. Respiration by simple diffusion. Nervous system consists of a nerve ring and many longitudinal nerve cords. Only sexual reproduction. Sexes are separate with sexual dimorphism. Males are usually shorter than females. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ascaris」の詳細全文を読む スポンサード リンク
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