Trichinella spiralis. Trichinella spiralis Common name: Trichina worm- The Pork worm Trichinella spiralis means spira, how this coils up in its host . diseases: Trichinosis, Trichiniasis, is a zoonotic disease. it is passed between humans and animals.
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The sperm fertilizes the egg, but the female doesn’t release the eggs until they have hatched within her uterus, which is usually within the fifth or sixth day of infection.
Female worms can produce approximately 1500 newborn larvae (immature L1) during a life span (4-16 weeks), before expulsion by the host immune system.
Expel active larvae
or early cleavage stage.
Ovoviviparous: Eggs laid containing embryo or
larva (L1). Some hatch out prior to passage
Viviparous: Expel active larvae
Anterior end: slender with small non papilated mouth.
posterior end ventrally curved
with 2 copulatory appendages
Female: 3.5mm single ovary
Posterior end bluntly rounded
Measures 80-120 um by 5.6 u at birth
And grows but little until it has entered
A muscle fiber, size 900 um
The mucosa of small intestine
Directly into the lymphatics
The larvae carried to all parts of body,
but the larvae developing only in striated muscle.
1--Penetration of the adult females into mucosa
The first symptoms appear between 1- 2 days after ingestion.
The worms migrating in the intestinal epithelium
Inflammation of duodenal and jejunal mucosa:
sweating, and diarrhea.
Ten days after infection the larvae will penetrated the muscle fibers, carried to all parts of body, This causes
Adult female worm:
The anterior two-thirds of the body being very thin
(looks like a whip)
and the remaining posterior end is thick and linear.
Size: 3.5-5cm in length
Adult Male worm:
smaller than the female, 3.0-3.5cm.
The posterior end is curved and has a single spicule
enveloped with sheath.
(looks like a whip).
has a single spicule
enveloped with sheath
Size: 50-55 x 25-30μm
Shell: thick egg shell with 2 polar plugs
Content: immature egg cells
3000-10000 eggs daily daily output
• Eggs pass out immature
• Embryo develops inside the egg (that takes about 3weeks at 25C)
• Mature eggs swallowed 1st stage larvae hatch in small intestine and penetrate villi
• Then migrate to large intestine and attach to mucosa with the thin anterior end
• After 2-4 month females mature and lay eggs.
4- abdominal pain
5- anemia may be the result of hemorrhaging when the worms mucosal damage))penetrate the intestinal wall
Children’s infection can cause rectal prolapse, The reason is the cecum is damaged by the worm, the cecum can be pushed out from the anus.
1- Eggs or worm in feces. Eggs are oval, barrel shaped,
2- Eosinophilia may occur.
3- In heavy infection proctoscopy or sigmoidoscopy,can show the worms attached to the mucosa.
4- Visual detection of adult worms on prolapsed rectum.