What is cysticercosis?

Definition

Cysticercosis is an infectious disease caused by the parasite
Taenia solium, which is a pork tapeworm.
This parasite invades the central nervous system and causes cysts to form
in various parts of the body, including the eyes, muscles, brain, and nervous
system. Cysticercosis is a major cause of epileptic seizures, especially in the developing world. Although the
prognosis is usually good, cysticercosis can lead to serious consequences,
including blindness, brain damage, and heart failure.

Causes

Cysticercosis is caused by ingestion of T. solium eggs, which are found in foods that have been contaminated or cooked improperly. Once consumed, the eggs hatch and their embryos penetrate the intestinal wall and enter the bloodstream.

Risk Factors

Risk factors for cysticercosis include eating meats, vegetables, or fruits that are contaminated with T. solium. Such contamination can occur if foods are not washed or cooked properly.

Symptoms

In many cases, cysticercosis does not produce symptoms. If the parasite invades
muscle tissue, lumps may be visible beneath the skin. If the eyes are involved,
symptoms may include blurred vision and detachment or swelling of the retina. If
the disease invades the nervous system, it is often accompanied
by seizures, headaches, brain swelling, and problems with balance.

Screening and Diagnosis

Establishing the diagnosis of cysticercosis can be challenging and requires
various tests. Blood tests can be used to detect antibodies to
T. solium. Imaging studies such as X rays, computed
tomography, ultrasonography, and magnetic resonance imaging can aid in visualizing
the cysts. Biopsies can be performed on infected tissue. Electroencephalographs
are useful if seizures are present. A spinal tap (lumbar puncture) may be
appropriate for some persons.

Treatment and Therapy

Consultation with an infectious disease specialist is highly recommended.
Treatment should be tailored to each patient, based on multiple factors, including
the symptoms, the stage of cyst development, and the site and quantity of cysts.
Treatment may involve corticosteroids, anticonvulsant
medications, and antiparasitic agents. Although antiparasitic agents are effective
for expelling parasites, they may produce a reactive localized inflammation.
Multiple courses of treatment may be needed to fully eliminate the cysts. If
seizures are present, referral to a neurologist is helpful for determining
appropriate therapy. In some cases, surgery or shunting may
be needed.

Prevention and Outcomes

Public education is extremely important for preventing cysticercosis. One should properly handle and cook food; fruits and vegetables should be washed thoroughly. One should not consume raw or undercooked pork. The risk of person-to-person transmission can be reduced by exercising good personal hygiene, including frequent handwashing. No vaccine against T. solium infection is available.

Bibliography

Garcia, H. H., et al. “Taenia solium Cysticercosis.” The Lancet 16 (2003): 547-556.

Icon Group. Cysticercosis: Webster’s Timeline History,1909-2007. San Diego, Calif.: Author, 2009.

Penrith, M. L. “Cysticercosis Working Group in Eastern and Southern Africa.” Journal of the South African Veterinary Association 80 (2009): 206-207.

Roberts, Larry S., and John Janovy, Jr. Gerald D. Schmidt and Larry S. Roberts’ Foundations of Parasitology. 8th ed. Boston: McGraw-Hill, 2009.

Singh, Gagandeep, and Sudesh Prabhakar. “Taenia solium.” Cysticercosis: From Basic to Clinical Science. Cambridge, Mass.: CAB International North America, 2002.

World Health Organization. “Taeniasis/Cysticercosis.” Available at http://www.who.int/zoonoses/diseases/ taeniasis.