Medical Parasitology

1. Trichuris trichiura
The whipworm
Lecture by: Osman H. Ali

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Introduction
• Trichuris trichiura or Trichocephalus trichiuris is intestinal
nematode worm
• Inhabit a human large intestine (ceacum)
• Causing the disease known as trichiuriasis
• It is soil transmitted infection (eggs are infective stage found in soil)
• Is commonly known as the whipworm because it looks like the whip

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4. • The worms has thin anterior and thick posterior part
• They attach to intestinal mucosa by embedding their anterior part.
• They feed on tissue fluid (not blood).
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Geographical distribution:
• Worldwide distribution
• It is more common in Asia
• Less in Africa and South America.
• Rare in the United states.

6. Morphology (the worm)
Shape: round
• narrow long anterior part end and
shorter and thicker posterior.
Color: pinkish-white
Size:
♀ 35–50 mm long
♂ 30–45 mm, with a coiled
posterior end
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7. Eggs of Trichuris trichiura
•Shape: oval (barrel-shaped)
has polar hyaline mucoid
blugs
• Size: 60 x40 µm
• Color: honey brown
• Shell: Thick
• Contents:
• Mass of granules
(Unembryonated)
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8. T.trichura eggs
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9. Development of T.trichura eggs
1 Eggs are single celled when passed with human feces
2The develop into 2 cell, 4 cell, morula, egg contain larva (in soil ) 3-Thelarvated egg
(infective to human)
• The development of infective eggs in soil takes about 2-3weeks,
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How man become infected?
• Infection to man is by ingestion of the infective eggs (contain larva) that may be in
contaminated food or drink, hands with soil
• The larva hatch in the human small intestine then migrate to large intestine
• They attach to mucosa of the large intestine.
• Then develop into mature worms with in three months
• After mating female produce 2,000–10,000 single-celled eggs per day
• which come out with feces.
• Worms can live up to five years

11. Life cycle
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Pathology & Symptomatology
People with light infections usually have no symptoms.
 People with heavy infection show symptoms like:
• Frequent defecation
• Painful passage of stool
• Stool appearance: contains a mixture of mucus and blood (dysentery).
• The clinical feature is identical to amebic dysentery.

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Complications:
• Colonic obstruction because of the tangle of worms
• Ulceration of large intestine which result in blood loss.
• Iron deficiency anemia
• Rectal prolapse

14. Rectal prolapse
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Laboratory Diagnosis
1 what is /are suitable sample/s?
2what is are suitable diagnostic test/s or technique/s?
3- what is/are the diagnostic stage/s?

16. Summary:
• T. trichuria worm inhabit human large intestine
• The female produces large number of eggs 2,000–10,000 per day
• The worms are not found stool because they attach to the mucosa of
large intestine.
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1 Stool sample is suitable for the diagnosis.
2 suitable diagnostic technique:
A- direct wet examination for feces (heavy infection)
B-Concentration by sedimentation or by floatation to detect (very light
infection)
3 diagnostic stages:
eggs

18. Quality control
• Eggs of T. trichiura should be differentiated from
Capillaria philippensis eggs which may also found in stool.
C. Philippensis egg T.trichiura egg
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Treatment
Several anthelmintics drugs of choice:
• Albindazole
• Mebendozle
Prognosis
The prognosis is good in light infection Poor in heavy chronic
infection

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Prevention & control
• Prevent contamination of soil with human feces
• Construction of latrines
• Washing hands before eating (children, soil worker).
• Washing vegetables & fruits
• Do not use the night soil as fertilizer