December 18, 2012
The trichinella spiralis is the smallest known nematode. There are three different types of ecological life cycles of the nematodes. The cycles are called urban, sylvatic, and marine cycles. The trichinella species is found worldwide. They are prevalent in Mexico, the northern hemisphere, parts of South Asia, Africa, South America, and Middle East. In the urban cycle the nematodes are carried by pigs and rats. In the sylvatic cycle they are hosted by walruses, wales, and polar bears.
The male’s nematode is 1.4 mm in length. The female is twice the size of the male. The body of the worm is more slender at the anterior than the posterior. The anterior end of the female contains hatching juveniles. The female is ovo-vivparious. This means that she produces eggs but doesn’t lay them until they have already hatched in the uterus. The nematode is also made up of three layers. The outer layer is called the cuticle layer. The cuticle layer protects the nematode so they can invade in the digestive tracts of animals. The life cycle of the nematode begins after ingestion of the first from the intermediate host. The worm molts four times within the first thirty hours and then mates. Then they move through the veins into the bloodstream. The larvae grow within the muscles causing a cyst. After a cyst is formed the worm cannot migrate any further. The only way the species can continue the life cycle is to be ingested by another host. Humans may know this parasite through the disease that is causes. This nematode can cause a serious infection in the human body calls trichinella or trichinosis. The human body can obtain this worm by eating meat that is already infected. The onset of the infection typically occurs within the first 24-48 hours after ingestion. The stage usually takes 4-8 weeks to complete and produces a different range of symptoms. Generally...
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