Tapeworms can cause intestinal infections. When they do, any of a number of tapeworm species may be involved. These may include Taenia saginata (beef tapeworms), Taenia solium (from pork), or Diphyllobothrium latum (from fish). Tapeworms require human hosts to live out their life cycles. They affect people through contact with contaminated human feces found in soil, fresh water, or food. Children can develop these diseases by eating raw or undercooked meat from animals or fish that are infected with tapeworms. Contaminated food contains cysts of the parasite. Your child may have a tapeworm infection and have no symptoms.
When a child eats tapeworm cysts in undercooked beef, pork, or fish, the cyst survives the stomach acids and releases the larvae. The parasite grows within the child’s bowel to become an adult tapeworm. The adult tapeworm has up to 1,000 segments called proglottids, each of which contain 30,000 to 100,000 eggs. A proglottid separates from the adult and travels out of the intestines with the stool. The segment is about 0.5 to 1 inch in length and can sometimes be seen moving in the stool or on the anus. If a child or adult has an adult tapeworm, they will pass segments filled with eggs in their stools.
These eggs are then released onto soil and eaten by cattle or pigs, in which they hatch, enter the bloodstream, and form cysts in the meat, completing the parasitic life cycle. These eggs can also get onto the hands of humans and then into foods that they are preparing. The eggs of the fish tapeworm do not affect humans. These eggs need a different host called a copepod, which is a small fresh-water shrimplike animal. The copepod is eaten by a fish, which then becomes contaminated with the tapeworm, thus completing the life cycle. The eggs of the beef tapeworm also do not affect people. However, when a person eats an egg from pork tapeworms, the egg hatches in the bowel and the larva emerges. The larva then burrows through the wall of the bowel to enter the bloodstream. Because the larva is not in a pig (the preferred host of a pork tapeworm), it cannot go through its normal life cycle. Thus, in its human host, the larva gets stuck in tissues such as the muscles, liver, and brain. Within the tissue, the larva forms a cyst. Cysts within the brain can cause seizures.
When adult tapeworms cause human illness, doctors use the name taeniasis to describe the infection. In contrast, when pork tapeworm larvae lead to illness, it is called cysticercosis.
Tapeworm infections tend to be more common in parts of the world with poor sanitation systems or where beef, pork, and fish are eaten raw or poorly cooked. Some tapeworms can grow up to 30 feet and live as long as 25 years!
Signs and Symptoms
Many tapeworm infections are symptom free. When symptoms are present, they often include
- Nausea
- Diarrhea
- Stomach pain
Fish tapeworm competes with its human host for vitamin B12 in the intestine and, in prolonged cases, can cause pernicious anemia.
Children who ingest pork tapeworm eggs can develop tapeworm cysts (cysticercosis) within their internal organs. If these cysts occur in the brain, they can cause serious symptoms such as seizures, behavioral disturbances, and even death.
When to Call Your Pediatrician
Contact your pediatrician if you notice something moving in your child’s stool that could be a worm segment, your youngster has prolonged stomach pain, or any of the other symptoms appear without another, more obvious cause. If you think your child might have been exposed to tapeworms within the past 2 to 3 months, let your pediatrician know. Make sure your doctor is aware if your child has traveled recently to a developing country.
How Is the Diagnosis Made?
To diagnose a tapeworm infection, your pediatrician will send your child’s stool sample for tests to detect eggs or worm segments of the suspected tapeworm. Children with cysticercosis usually do not have adult tapeworms. Therefore, eggs are not usually found in the stool. Blood tests can be done to look for antibodies to the tapeworm. In patients with seizures, imaging of the brain with computed tomography (CT) or magnetic resonance imaging (MRI) is performed to look for cysts or other abnormalities.
Treatment
Your pediatrician may prescribe oral drugs such as praziquantel or, as an alternative, niclosamide to treat a tapeworm infestation. These medicines are typically given in a single dose.
Other antiparasitic drugs, including albendazole and praziquantel, are available specifically for treating cysticercosis. Anticonvulsant medications should be used to control seizures if they occur.
What Is the Prognosis?
Drug treatment for tapeworms is very effective and can completely kill the parasite. Treatment for the cysts will get rid of them, but the area of the brain may remain abnormal and seizures may continue.
Prevention
To reduce your child’s risk of developing tapeworm infections, do not allow him to eat raw or undercooked fish, beef, or pork. Be sure he always practices good hygiene, including regular hand washing, especially after using the bathroom. To avoid cysticercosis, be sure that all food handlers wash their hands. Proper sanitation is the key to the elimination of tapeworm infestation worldwide.