Pinworms
Common Name: Pinworm
Scientific Name: Enterobius
Phylum: Nematoda
Class: Secernentea
Other Taxonomy: Order: Oxyurida Family: Oxyuridae Genus: Enterobius
Specimen #: 73
Circumstance: Observed online
Specimen Condition: Specimen presumed alive
Typical Habitat: infection in the United States and Western Europe
Invasive? Not an invasive species
Natural area of growth: infection in the United States and Western Europe
Relationship with humans: In humans, enterobius vermicularis causes the medical condition enterobiasis, whose primary symptom is itching in the anal area.
Evolutionary Significance: from egg to adult—takes place in the human gastrointestinal tract of a single human host. The life cycle begins with eggs being ingested. The eggs hatch in the duodenum (i.e., first part of the small intestine). The emerging pinworm larvae grow rapidly to a size of 140 to 150 micrometers in size, and migrate through the small intestine towards the colon. During this migration they molt twice and become adults. Females survive for 5 to 13 weeks, and males about 7 weeks. The male and female pinworms mate in the ileum (i.e., last part of the small intestine), whereafter the male pinworms usually die, and are passed out with stool. The gravid female pinworms settle in the ileum, caecum (i.e., beginning of the large intestine), appendix and ascending colon, where they attach themselves to the mucosa and ingest colonic contents. Almost the entire body of a gravid female becomes filled with eggs. The estimations of the number of eggs in a gravid female pinworm range from about 11,000 to 16,000. The egg-laying process begins approximately five weeks after initial ingestion of pinworm eggs by the human host. The gravid female pinworms migrate through the colon towards the rectum at a rate of 12 to 14 centimeters per hour. They emerge from the anus, and while moving on the skin near the anus, the female pinworms deposit eggs either through (1) contracting and expelling the eggs, (2) dying and then disintegrating, or (3) bodily rupture due to the host scratching the worm. After depositing the eggs, the female becomes opaque and dies. The reason the female emerges from the anus is to obtain the oxygen necessary for the maturation of the eggs.
Sources: http://en.wikipedia.org/wiki/Enterobius
http://www.nlm.nih.gov/medlineplus/pinworms.html
Scientific Name: Enterobius
Phylum: Nematoda
Class: Secernentea
Other Taxonomy: Order: Oxyurida Family: Oxyuridae Genus: Enterobius
Specimen #: 73
Circumstance: Observed online
Specimen Condition: Specimen presumed alive
Typical Habitat: infection in the United States and Western Europe
Invasive? Not an invasive species
Natural area of growth: infection in the United States and Western Europe
Relationship with humans: In humans, enterobius vermicularis causes the medical condition enterobiasis, whose primary symptom is itching in the anal area.
Evolutionary Significance: from egg to adult—takes place in the human gastrointestinal tract of a single human host. The life cycle begins with eggs being ingested. The eggs hatch in the duodenum (i.e., first part of the small intestine). The emerging pinworm larvae grow rapidly to a size of 140 to 150 micrometers in size, and migrate through the small intestine towards the colon. During this migration they molt twice and become adults. Females survive for 5 to 13 weeks, and males about 7 weeks. The male and female pinworms mate in the ileum (i.e., last part of the small intestine), whereafter the male pinworms usually die, and are passed out with stool. The gravid female pinworms settle in the ileum, caecum (i.e., beginning of the large intestine), appendix and ascending colon, where they attach themselves to the mucosa and ingest colonic contents. Almost the entire body of a gravid female becomes filled with eggs. The estimations of the number of eggs in a gravid female pinworm range from about 11,000 to 16,000. The egg-laying process begins approximately five weeks after initial ingestion of pinworm eggs by the human host. The gravid female pinworms migrate through the colon towards the rectum at a rate of 12 to 14 centimeters per hour. They emerge from the anus, and while moving on the skin near the anus, the female pinworms deposit eggs either through (1) contracting and expelling the eggs, (2) dying and then disintegrating, or (3) bodily rupture due to the host scratching the worm. After depositing the eggs, the female becomes opaque and dies. The reason the female emerges from the anus is to obtain the oxygen necessary for the maturation of the eggs.
Sources: http://en.wikipedia.org/wiki/Enterobius
http://www.nlm.nih.gov/medlineplus/pinworms.html