Nematodes comprise a large group of organisms, the majority of which are free-living. Characteristically, they are nonsegmented round worms, and the sexes are separate and usually morphologically distinct. The life cycles of parasitic nematodes can be rather simple. For example, some species of nematodes lay eggs that leave the host in feces and embryonate in soil. In these cases, the eggs enter the host by the oral route and the worms develop to adults in the intestinal tract. Other species of nematodes have more complex cycles, involving intermediate invertebrate or vertebrate hosts, often with complex migration routes, once inside the host. The route of entry into the host can also vary, with some species being capable of penetrating directly into the host through the unbroken skin. Nematode parasites have been selected for life in a broad spectrum of niches within the mammalian host, including intracellular and intramulticellular environments.
KeywordsBlood Meal Adult Worm Reservoir Host Female Worm Ascaris Lumbricoides
Unable to display preview. Download preview PDF.
- Campbell WC (ed): Trichinella and Trichinosis. New York, Plenum, 1983Google Scholar
- Croll NA (ed): The Organization of Nematodes. London and New York, Academic Press, 1976Google Scholar
- Crompton DWI, Nesheim MC, Pawlowski ZF (eds): Ascariasis and Its Public Health Significance. London and Philadelphia, Taylor and Francis, 1985Google Scholar
- Kim CW (ed): Trichinellosis. Albany NY, New York State University Press, 1985Google Scholar
- Zuckerman BM (ed): Nematodes as Biological Models, Vol 1, 2. London and New York, Academic Press, 1980Google Scholar