Rev 02/21/2024
Enterobius vermicularis an important human parasite species
Prevalence differs widely in different regions of the world. Personal hygiene, hand-washing are important avoidance tactics. Infections can be especially prevalent in young children playing on the ground.
E. vermicularis is an intestinal parasite of humans. Usually found in the intestinal lumen but occasionally in the intestine wall or in tissues outside the intestinal tract.
Cameron, 1929 noted: "The genus Enterobius is a peculiar one among the parasites of primates in that its life history tends to make it a parasite of the individual. Its eggs do not tend to be broadcast as do those of the other helminths and consequently there must be a tendency for any one species of parasite to restrict itself to the same species of host.........to one genus of host rather than to one species; in other words the evolution of the parasite is slower than that of the primate".
Different species are parasites of humans, chimpanzees, orangutangs, monkeys, loris, baboons, gorillas and others
Pinworm parasites of vertebrates.
In E. vermicularis, the entire life cycle, from egg to adult, takes place in the intetine of a single host between 2 and 8 weeks.
There are four molts; the first two within the egg before hatching and two before becoming adults. Larvae hatching from eggs gow rapidly to lengths of +/- 150 microns and migrate through the small intestine to the colon. Females survive up to 13 weeks and males about 7 weeks. Mated famales establish feeding sites in the mucosa of the intestine. The body of the gravid female becomes filled with 11,000 to 16,000 eggs. The females migrate to the rectum and anus where they release eggs and then die.
The parasitic disease in humans is known as enterobiasis or oxyuriasis. Usually not very dangerous. Sometimes infections occur in the pelvic region or urinary tract of women.
May cause symptoms similar to appendicitis.
Cameron, T.W.M. 1929. The Species of Enterobius Leach, in Primates. J. Helminthol. 7:161-182.
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