COENUROSIS: Tapeworm Larva Cysts ~ Soft Tissue, Muscles, Eyes, & CNS

It's important to distinguish the significant difference between a human Tapeworm Infection & Coenurosis.

Humans are definitive hosts for many types of tapeworms, the most common being T. saginata & T. solium (beef & pork tapeworms).  These develop into reproductive adult worms in the intestines of humans.  A person infected with these species has a Tapeworm Infection.

In contrast, the four species that cause human Coenurosis can only grow into mature reproductive worms in their definitive canid hosts, such as dogs, wolves, foxes, & coyotes.

Humans who ingest eggs from any of these four Taenia species are intermediate hosts, where the eggs can mature into larvae but not into adult worms.

Many animals serve as intermediate hosts, including rodents, rabbits, cattle, sheep, goats, & humans by ingesting the eggs.

Once ingested, the eggs hatch in the intestines, releasing oncospheres.  These circulate in the blood & lodge in body organs, subcutaneous tissue, skeletal muscles, eyes, CNS, or spinal chord.

After about three months, the oncospheres develop into cystic-like larva balls called coenuri.

The cycle perpetuates when a canid (definitive host) ingests the tissue of an infected intermediate host. 

When this happens, the maturing larva reside in the small intestine of the definitive host, mature into adult worms, & begin producing eggs.  These pass through feces into the environment once again.

The species T. brauni, T. serialis, & T. glomerulus cause subcutaneous tissue & muscle infection.  When coenuri develop in muscles, a painful nodule often results, & a visceral larval migrans syndrome may develop.

Subcutaneous coenuri produce a nodule similar to those in muscle tissue, but it tends to be painless.  The nodules are usually smaller than 6 centimeters in diameter.  They are commonly located in the trunk but can also be found in the neck, head, or limbs. 

Systemic allergic symptoms have also been reported in cases of Coenurosis of the breast. 

In the eye, the coenuri take on either an intraocular or orbital form in the subconjunctival space, eyelids, or extrinsic muscles.  The symptoms are blurred vision or diplopia. 

If coenuri enter the brain, meningeal symptoms may include headache, transient hemiparesis, & epileptiform seizures, increased intracranial pressure, & loss of consciousness.  The full-blown syndrome is a space-occupying lesion.

The tapeworm larva group together to form fluid-filled cysts in various body tissues.  A cysts starts out small, but as the larva grow, it can reach the size of an egg.

The cysts of T. multiceps are usually between 2 and 6 cm in diameter & can contain a few to over a hundred worm larva.  They encyst in subcutaneous tissue, CNS, muscles, or eyes.

T serialis & T. glomerata cysts present in the CNS, muscles, or soft tissue. 

T. brauni cysts occupy these same areas but occur in the eye more frequently than the other three species.

When a cyst occurs in the brain, symptoms are headaches, seizures, vomiting, paralysis affecting one side of the body (hemiplegia), paralysis involving one limb (monoplegia), & loss of ability to coordinate muscles & muscle movements.  These symptoms are due to buildup of inter-cranial pressure from the growing cyst or from the cyst pressing on other parts of the brain.

If a cyst occurs in the spinal chord, it can cause severe pain, inflammation, & loss of feeling in some nerves.

A cyst in the eye causes decreased vision & headaches.

In muscular & subcutaneous tissue, the cyst can cause disfiguring nodules that protrude out of the body.  These nodules can be painful & cause loss of muscle function.

CT scans and MRIs are used to detect fluid-filled cysts in all areas of the body.  Serological & microscopic tests can confirm Taenia larva when a portion of a cyst is surgically removed for examination & biopsy.

Because of a lack of specific diagnostic techniques, Coenurosis can be misdiagnosed as Cysticercosis, Neurocysticercosis, or Echinococcos, which are other parasitic diseases of soft tissue, muscles, eyes, organs, or CNS.

If a person with symptoms lives in an area with poor sanitation, high wild dog population, or known endemic tapeworm, the chance of having Coenurosis is high.

This disease occurs more often in children because they spend more time outside than adults & are more likely to come into contact with canid feces.

Also at risk of infection are persons who reside, camp, garden, landscape, work, or hike in rural, wooded, or wildlife areas.

Praziquantel (Biltricide):  Causes cell membranes of worms to become permeable.  In this way, the worm loses intracellular calcium.  This in turn causes the worm to become paralyzed.

Niclosamide (Niclocide):  By causing the death of cells in the head & adjoining segments, this drug causes the worm to let go of whatever it's attached to in the human body.  The worm is then excreted in the feces.

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