I bet a lot of you are like me when you watch the TV show House, you probably sit there and try to figure out what obscure disease their patient has. Well, I was watching an episode the other day (must have been an old one) and actually figured out what the poor schoolteacher had; she had a case of neurocysticercosis from the eggs of the pork tapeworm.
What is the pork tapeworm?
Taenia solium is a tapeworm that people get from eating raw or undercooked “measly pork”. The pork meat has cysticerci (the larval stage) which in the human intestine mature to an adult tapeworm. Here the tapeworm attaches to the intestine and produces thousands of eggs.
Does the pork tapeworm cause disease while in the intestine?
Most people are asymptomatic and only become aware of the tapeworm by noticing segments of the worm in their feces. Symptoms of infection, if any, are general: nausea, intestinal upset, vague abdominal symptoms such as hunger pains, diarrhea and/or constipation, or chronic indigestion.
What is cysticercosis?
Human cysticercosis occurs either by the direct transfer of Taenia solium eggs from the feces of people harboring an adult worm to their own mouth (autoinfection) or to the mouth of another individual, or indirectly by ingestion of food or water contaminated with the eggs. When the person ingests the eggs, the embryo escape from the shell and penetrates the intestinal wall, gets into the blood vessels, where they spread to muscle, or more seriously, the eyes, heart or brain.
How serious is cysticercosis?
The severity of cystercercosis depends on which organs are infected and the number of cysticerci. An infection consisting of a few small cysticerci in the liver or muscles would likely result in no obvious disease and go unnoticed. Those that form in voluntary muscle tend to be asymptomatic, but may cause some pain. On the other hand, a few cysticerci, if located in a particularly “sensitive” area of the body, might result in irreparable damage. For instance, a cysticercus in the eye might lead to blindness, or a cysticercus in the brain (neurocysticercosis) could lead to traumatic neurological damage, epileptic seizures or brain swelling that can kill.
Is this a problem in the United States?
This condition is relatively common in Mexico and large parts of Central America. It is seen most frequently in the Southwest U.S., but can be seen in other parts of the country. It is most frequently associated with immigrants to this country.
How long after infection do symptoms of cysticercosis appear?
It may be as short as a few weeks or up to 10 years or more.
Is it treatable?
It can be treated with anti-parasitic drugs like praziquantel and steroid therapy to control brain swelling. Occasionally surgical intervention may be required to relieve symptoms.
How do you prevent this disease?
In the U.S., laws have been passed that requires meat inspection for cysticerci prior to meat being put on the market of human consumption.
Adequate cooking of meat destroys the tapeworm larvae and will prevent infection by tapeworm. Freezing meat to -5C for 4 days, -15C for 3 days, or -24C for 1 day kills the larvae as well.
Good hygiene and hand washing after using the toilet will prevent self-infection in a person already infected with tapeworms in addition to contamination of foodstuffs by human feces.