Tapeworms in the intestines usually cause mild disease. Immature tapeworms, called larval cysts, can cause serious disease in other parts of the body.
A tapeworm is a parasite that can live and feed in human intestines. This is called a tapeworm infection.
A young and inactive form of the tapeworm is called a larval cyst. It can stay alive in other parts of the body. This is called a larval cyst infection.
A tapeworm in the intestines often causes mild symptoms. Moderate to severe symptoms may include stomach pain and diarrhea. Larval cysts can cause serious disease if they are in a person's brain, liver, lungs, heart or eyes.
Tapeworm infections are treated with anti-parasitic drugs. Treatments for larval cyst infections may include anti-parasitic drugs and surgery to remove the cyst. Other drugs may be used to treat symptoms.
Symptoms depend mostly on where the infection happens in the body.
A tapeworm in the intestines may cause no symptoms. The severity of symptoms depends in part on the number of tapeworms. Symptoms vary. And some symptoms are more likely with some species of tapeworm. Symptoms may include:
Symptoms of larval cyst infection depend on where they are causing disease in the body.
If you experience any of the symptoms of tapeworm or larval cyst infection, get medical care.
Most tapeworms need two different hosts to complete a life cycle. One host is the place where a parasite grows from egg to larva, called the intermediate host. The other host is where the larva become adults, called the definitive host. For example, beef tapeworms need cattle and humans to go through a complete life cycle.
The beef tapeworm eggs can survive in the environment for months or years. If a cow, the intermediate host, eats grass with these eggs on it, the eggs hatch in its intestines. The young parasite, called a larva, passes into the bloodstream and moves to muscles. It forms a protective shell, called a cyst.
When people, the definitive host, eat undercooked meat from that cow, they can develop a tapeworm infection. The larval cyst develops into an adult tapeworm. The tapeworm attaches to the wall of the intestine where it feeds. It produces eggs that pass in the person's stool.
In this case, the cow is called the intermediate host, and the person is the definitive host.
Humans are the definitive hosts for some species of tapeworms. They may get a tapeworm infection after eating raw or undercooked:
Humans may be the intermediate hosts for other tapeworm species. This usually happens when they drink water or eat food with tapeworm eggs. Humans also can be exposed to eggs in dog feces.
An egg hatches in the person's intestines. The larva travels through the bloodstream and forms a cyst somewhere in the body.
The larval cyst matures. But it won't become a tapeworm. Cysts vary by species. Some cysts have a single larva. Others have several larvae. Or they can make more. If a cyst bursts, it can lead to cysts forming in other parts of the body.
Symptoms usually show up years after the infection began. They happen when the immune system responds to the cyst shedding debris, breaking down or hardening. Symptoms also appear when one or more cysts keep an organ from working correctly.
There are two exceptions to the typical life cycle of tapeworms that can infect humans.
Factors that may put you at greater risk of tapeworm or larval cyst infection include:
Tapeworm infections usually don't cause complications. Problems that may happen include:
Complications from larval cysts vary depending on what organ is affected. Serious complications include the following.
These steps can help prevent infections with tapeworms or tapeworm larval cysts.
A health care provider tests for a tapeworm infection in the intestines using a test of a stool sample. A lab test may find pieces of tapeworms or eggs. You may give a sample on more than one day.
Your health care provider treats a tapeworm infection in the intestines with anti-parasitic drugs. These include:
These drugs kill the tapeworm but not the eggs. You need to wash your hands well with soap and water after using the toilet. This protects you and other people from the spread of tapeworm eggs.
Your health care provider will schedule follow-up appointments. They use tests of stool samples to see if the treatment has worked.
Treating a larval cyst infection depends on the location or effects of the infection. Treatments often include:
Other treatments to manage complications and symptoms may include:
You'll likely see your health care provider first. You may be referred to a doctor who treats problems in the brain and central nervous system, called a neurologist. Or you may see a doctor who treats problems in the digestive system, called a gastroenterologist.
To prepare for your appointment, write down answers to the following questions.