Taenia solium “The Pork Tapeworm”

Taeniasolium“The Pork Tapeworm”

Taenia solium Taenia solium causes two different diseases… • 2.) taeniasis – digestive tract • Develops when adult tapeworm infects human intestine • 3-6 feet long • Asymptomatic but continuous source of eggs in the feces • 1.) cysticerosis – muscle tissues • Eggs cross digestive tract, enter circulation, and lodge in muscle tissues • If it’s in the brain it’s neurocysticerosis

Taenia solium Pig muscle infected with cysticerci Morphology Larvae • Tapeworm Larvae enters body and forms… • cysticerci which are 6- 18mm wide by 4 - 6mm in length when found in the muscle tissue. • However, it may also be found in other tissues such as in the C.N.S. where they may grow up to several cm in diameter!

Taenia solium Affects in the Human - Larva The annual mortality rate is approximately 50,000 cases worldwide!

Taenia solium Eggs or gravid proglottids are passed through “feces” Pigs become infected by consuming infected eggs or gravid proglottids In the pig’s intestine, the oncosphere hatches The oncosphere invades the intestinal wall and migrates to the striated muscles, where they develop into cysticerci In the human intestine, the cysticercus develops over 2 months into an adult tapeworm, which can survive for years. The tapeworm attaches to the small intestine by their scolex. Life Cycle

Taenia solium Hosts to T. solium • Humans are the only definitive host for T. solium (absolute host specifity).

Taenia solium Taenia solium eggs T. solium eggs

Taenia solium Intermediate Host - Pigs Intermediate Host (Pig) consumes infected eggs T. solium eggs

Taenia solium Definitive Host - Humans Definitive Host (Human) consumes infected pork (Measly) Pork is infected with tapeworm cysticerci Intermediate Host (Pig) consumes infected eggs T. solium eggs

Taenia solium Rostellum (with roughly 30 hooks) The gravid proglottids are 12mm x 6mm each scolex The strobila consists of between 800 and 1000 proglottids. Each proglottid may produce 50,000 eggs respectively! Morphology Adults The adult tapeworms are around 10 feet, but may grow up to 27!

Taenia solium • However, sometimes there are non-specific symptoms that form such as constipation or diarrhea. • Occasionally, appendicitis can result from migrating proglottids. • Very rarely is there perforation of the intestinal wall, but when it does occur it is called peritonitis. • 25% of cysticercosis infections are aquired by the autoinfection.

Taenia solium Risk Factors • 50,000 cases reported globally a year! • However it is VERY rare in Islamic countries where there is little consumption of pork • Poorer countries or more at risk for these parasites because they are in close contact with pigs and eat undercooked pork more often than developed countries. • Latin American Countries especially are at high risk and experience many cases of pork tapeworms.

Taenia solium • Don’t eat poop. • Try to keep stable, sanitary conditions in impoverished areas. • Ensure that pork is cooked thoroughly before eaten. Prevention

Taenia solium Diagnosis and Treatment Diagnosis • Cysticercosis - can appear from 10 days to 10 years after infection. • Taeniasis - eggs occur in stool 8-12 weeks after infection. • Stool samples can diagnose both cysticercosis and teniasis but is not possible during the first 3 months following infection. Treatment • Treatment is simple and very effective. Praziquantel is the drug of choice. • Appropriate drug therapy seems to be the only treatment. There is no immunization available at this time.

Microscopic examination of stool for ova and proglottids CT and/or MRI and serologic testing for patients with CNS symptoms Infection with adult T. solium worms can usually be diagnosed by microscopic examination of stool samples and identification of eggs and/or proglottids. However, T. solium eggs are present in ≤ 50% of stool samples from patients with cysticercosis. Cysticercosis is usually diagnosed

when CT or MRI is done to evaluate neurologic symptoms. Scans may show solid nodules, cysticerci, calcified cysts, ring-enhancing lesions, or hydrocephalus. The CDC's (Centers for Disease Control and Prevention's) immunoblot assay (using a serum specimen) is highly specific and more sensitive than other enzyme immunoassays (particularly when > 2 CNS lesions are present; sensitivity is lower when only a single cyst is present).

TREATMENT For intestinal infection: Praziquantel or niclosamide For neurocysticercosis: Corticosteroids, anticonvulsants, and sometimes albendazole or praziquantel and/or surgery Intestinal infection is treated with praziquantel 5 to 10 mg/kg po as a single dose to eliminate adult worms. Praziquantel should be used with caution in patients who also have neurocysticercosis because by killing cysts, praziquantel

may trigger an inflammatory response associated with seizures or other symptoms. Alternatively, a single 2-g dose of niclosamide is given as 4 tablets (500 mg each) that are chewed one at a time and swallowed with a small amount of water. For children, the dose is 50 mg/kg once. Symptomatic neurocysticercosis is treated with corticosteroids (prednisone 60 mg po once/day or dexamethasone 6 mg po once/day) to reduce inflammation and symptoms and anticonvulsants to prevent seizures.

Anthelmintic treatment of neurocysticercosis is complicated, and consultation with an expert is recommended. Choice of treatment depends on the location, number, and stage of cysticerci, and clinical manifestations. Not all patients respond to treatment, and not all patients must be treated (cysts may already be dead and calcified, or the inflammatory response to treatment may be worse than the disease). When anthelmintic treatment is used, albendazole 400 mg po bid for 8 to 30 days is the drug of choice; praziquantel33.3 mg/kg potid on day 1 followed by 16.6 mg/kg potid for 29 days is an alternative. Either prednisone or dexamethasone is given concurrently with the

anthelminthic to reduce the inflammation that occurs in response to dying cysts in the brain. Neither albendazolenorpraziquantel should be used in patients with ocular or spinal cord cysticerci. Surgery may be necessary for obstructive hydrocephalus (due to intraventricularcysticerci), infection of the 4th ventricle, or spinal or ocular cysticercosis

Contains hooks (Rostellum) bladderworm or cysticercus of Taenia solium.

Taenia solium Taenia solium eggs Taenia solium removed Scolex of Taenia Solium

Taenia solium “The Pork Tapeworm”