The term “pinworm” refers to Enterobius vermicularis, a tiny, threadlike, white roundworm (formally known as a nematode) that infects the. Learn about pinworms, the facts on how the infection is spread, and the life cycle of how long it lasts in humans. Gravid females move outside the anus during the night and deposit eggs in the perianal area. The larvae in the egg become infective in approximately 4 hours.
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What Are Pinworms?
The nematode roundworm Enterobius vermicularis previously Oxyuris vermicularis also called human pinworm. Humans are considered to be the only hosts of E.
A second species, Enterobius gregoriihas been described and reported from Europe, Africa, and Asia. For all practical purposes, the morphology, life cycle, clinical presentation, and treatment of E. Eggs are deposited on perianal folds. Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area.
Person-to-person transmission can also occur through handling of contaminated clothes or bed linens. Enterobiasis may also be acquired through surfaces in the environment that are contaminated with pinworm eggs e. Some small number of eggs may become airborne and inhaled. These would be swallowed and follow vermocularis same development as ingested eggs. Following ingestion of infective eggs, the larvae hatch in the small intestine and the adults establish themselves in the colon.
CDC – Enterobiasis – Biology
The time interval from ingestion of infective eggs to oviposition by the adult females is about one month. The life span of the adults is about two months.
Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area. The larvae contained inside the eggs develop the eggs become infective in 4 to 6 hours under optimal conditions.
Retroinfection, or the migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens is unknown. Life cycle image and information courtesy of DPDx.
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