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42 Cards in this Set
- Front
- Back
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Where does the adult A. lumbricoides worm live? |
Lumen of the small intestines. The female produces 200,000 eggs which are passed in the feces |
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Two types of eggs are diagnostic in an A. lumbricoides. |
1. Fertilized eggs become infective in 18d-several weeks 2. Unfertilized eggs can be ingested but are not infective |
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How do A. lumbricoides get ingested? |
The eggs are swallowed the larvae hatch. |
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Where do the larvae head in A. lumbricoides? |
Invade the intestinal mucosa carried via to the portal systemic circulation to the lungs |
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Where do A. lumbricoides larvae mature? |
In the lungs Penetrate the alveolar wall ascend the bronchial tree to throat and are swallowed They reach the small intestines and develop into the adult worm |
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What is the timeline to egg to adult in A. lumbricoides? |
2-3 months from ingestion to ovipostion of adult female |
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Where are eggs deposited in E. vermicularis? |
In perianal folds |
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How does infection occur in an E. vermicularis infection? |
Infective eggs are transferred to mouth by hands via scratching. Also from handling contaminated articles or surfaces. |
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Where do E. vermicularis eggs develop? |
Infective eggs are ingested and the larvae hatch in the small intestines |
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Where are adult worms established in E. vermicularis? |
Adults are established in colon |
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How long does oviposition take in E. vermicularis? |
It takes one month from ingestion to adult |
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What is the life span of E. vermicularis? |
two months |
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What is the life span of A. lumbricoides? |
1 to 2 years |
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Where do female deposit their eggs in E. vermicularis? |
Gravid females migrate nocturnally outside the anus and ovipost whil crawling on the skin of the perianal area |
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How long does it take the eggs to mature in E. vermicularis? |
The larvae contained in the eggs develop in 4-6 hours under optimal conditions |
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What is a retroinfection in E. vermicularis |
migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens in unknown |
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Where are eggs deposited in Trichuris trichiura? |
Unembryonated eggs are passed with the stool. |
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What are the stages of eggs development in whipworm? |
They develop into a 2-cell stage Advance cleavage stage Then they embryonate |
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When do Trichuris trichiura become infective? |
Eggs become infective in 15 to 30 days. |
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Where do the whipworm eggs hatch? |
Eggs hatch in small intestines and release larvae they mature and become adults in the colon |
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Where do adult whipworm become established? |
Live in the cecum and ascending colon |
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What portion of the whipworm is threaded into the colon? |
anterior portions are threaded into the mucosa |
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When do the female whipworms begin to oviposit? |
60-70 day after infection 3000-20000 eggs per day |
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How long is the life span of Trichuris trichiura? |
About 1 year |
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What is the diagnostic form of Hookworm |
Egg that are passed in the stool and will hatch in 1 to 2 days |
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What is released from hookworm eggs? |
Rhabditiform larvae |
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How long does it take for the rhabditiform larvae to become filariform? |
5 to 10 days in feces or soil |
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What is the infective form of hookworm? |
Filariform |
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How does hookworm enter the human? |
Skin penetration |
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Where does the filariform travel in the human body? |
blood vessels to the heart then to the lungs. Penetrate pulmonary alveoli ascend the bronchial tree to the pharynx then swallowed |
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Where do adult hookworms live? |
Small intestines |
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How long do hookworms live? |
1-2 years but can live longer |
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Which hookworm requires the transpulmonary migration phase? |
N. americanus |
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What is the diagnostic form of Strongyloides? |
Rhabditiform in the stool |
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Free living cycle of strongyloides |
Rhabtitiform in the stool can molt: 2xs to become infective filariform in stool OR 4xs to become an adult |
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If the rhabditiform becomes an adult what happens? |
Males and females mate and produce eggs Rhabditifrom larvae hatch those can also turn into adults or become infective filariform |
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Infective form of strongyloides? |
Filiariform |
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How is the host infected by strongyloides? |
penetration of host skin |
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The parasitic life cycle of Strongyloides |
Filiariform penetrate skin transported to alveolar spaces carried to bronchial tree to pharynx and swallowed to small intestines |
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Where do strongyloides mature in the host? |
Small intestines molt twice |
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Where exactly do adults live in the host? |
Females thread into the epithelium of the small intestines and produce eggs |
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What happens to the eggs produced by Strongyloides females in the host? |
Autoinfection Rhabditiform mature in host (autoinfection) Rhabditiform larvae are passed into stool (free-living cycle) |
