cysticercosis

CYSTICERCOSIS OPTOM FASLU MUHAMMED

Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tape worm.

The disease is spread via the oral route through contaminated food and water, and is primarily a food born disease.

After ingestion the eggs pass through the lumen of the intestine into the tissue and migrate preferentially to the brain and muscles.

Cysticercosis should be differentiated from taeniasis carriage of the adult tape worm in the intestine (which is through ingestion of cysts in an intermediate host, not the ingestion of the eggs as in cysticercosis)

These represents two different stages of the parasite’s life cycle.

Agent: Taenia solium (pork tape worm) The common larval stage of Taenia solium

was also known as cysticercus cellulosa

TRANSMISSON Humans are Taenia solium reservoirs. Eating under cooked pork that contain viable

cysticerci. Large no. of eggs which pass out in the feces The presence of an adult tape worm in the

gut is reasonably harmless. This condition is known as cysticercosis.

LIFE CYCLE

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Two host life cycle Human beings are the only definitive host Both humans and pigs can act as

intermediate host

BASICS OF INFECTION CYCLE Tapeworm larval cyst (cysticercus) is

ingested with poorly infected meat. Larva escapes the cyst and attaches to the

mucosa by the scolex. Feces are contaminated with eggs (persists

for several days in the environment) consumed by pigs (eggs are hatched and form cysticerci)

Humans also can be the intermediate host causing cysticercosis if they ingest eggs.

Two different forms in human:- Human taeniasis Human cysticercosis

Human taeniasis The scolex attaches to the mucosa and

begins forming segments (proglottis) After two months of infection, gravid

proglotids begin to detach from the distal end- excreted in the feces.

Each segment contains 60,000 eggs Worm causes only minor inflammation to the

intestine(mild symptoms- abdominal pain, diarrhoea and naussea)

HUMAN CYSTICERCOSIS Internal auto infection is also possible The invasive oncoshere (embryos) the eggs

are liberated by the action of gastric acid and cross the bowel wall

They estalished at small terminal vessels (muscles, brain, eye) where they grow about the size of 1cm in 2-3 months.

Muscles: small, palpable, movable nodules Chest and arms: mild or no symptoms Ophthalmic cysticercosis: intraocular cysts

floating freely in the vitreous humor, decreased visual acuity

Neurocysticercosis: most symptoms are because of the inflammatory reactions associated with cyst degeneration (that may take years to happen)- epilepsy, hydrocephalus, encephalitis, meningitis

CYSTICERCOSIS IN MUSCLE Cysticerci can develop in any voluntary

muscle in humans Invasion of muscle by cysticerci can cause

myositis, with fever, eosinophilia and muscular pseudo hypertrophy