How a Tapeworm Infection Is Diagnosed

Tapeworms in poop look like little grains of white rice that may be moving. If you see tapeworms in your toilet, call your healthcare provider.

Tapeworms often don't cause obvious symptoms, and most people do not know they are infected. However, some tapeworm species, like the pork tapeworm (Taenia solium), carry the potential for serious, long-term complications.

If you see tapeworm in your poop, getting an accurate diagnosis is essential. Stool tests are used to determine the exact species of tapeworm to determine the proper treatment.

This article discusses tapeworm infections and how they are diagnosed.

Self-Checks

You aren't likely to notice any significant changes in the appearance of your poop unless a worm or a proglottid (tapeworm segment) passes during a bowel movement, and you happen to notice.

Tapeworms or tapeworm segments may be visible in the stool when they are passed along with a bowel movement. In particular, a head-like part of the tapeworm that has suckers and hook-like structures that attach to the intestine called a scolex, may be seen.

Scolices (more than one scolex) can appear round, diamond-shaped, or elongated, depending on the species. It's important to bring a stool sample containing any scolices to a physician or to a lab for a stool test.

What Do Tapeworms Look Like?

Although there are many different types of tapeworms, nearly all share similar physical characteristics:

• Flat, ribbon-like body
• A head with sucker-like appendages (which the worm uses to attach to the intestines)
• A neck
• A series of connected segments called proglottids that sometimes contain eggs and can break off from the head and neck

Most tapeworms that affect humans can grow up to 30 feet long, with the exception of dwarf tapeworms that reach a maximum of around 2 inches.

Labs and Tests

Your healthcare provider will order stool testing to determine the type of tapeworm infection and bloodwork to check for certain complications.

Stool Tests

Tapeworm infection may be diagnosed through a stool test. Tapeworms or eggs leave the body by passing through the intestines and ultimately end up in the stool. The part of the worm that leaves the body will differ based on the type of tapeworm that is causing the infection.

An ova and parasite exam looks for eggs (ova) and parasites (which include tapeworms). The technicians will use a microscope to examine eggs or worm segments called proglottids. Each species has unique characteristics that help to make an identification.

You will need to collect a stool sample for lab analysis. Your healthcare provider will likely provide a container and instructions. The Centers for Disease Control and Prevention recommends testing three different samples.

Blood Tests

Infection with the fish tapeworm (Diphyllobothrium latum) may lead to a lack of vitamin B12, which may cause anemia. A physician may order a blood test to check for these complications. Other blood tests may also be used, but this is not common.

Physical Exam

A physical exam may not turn up anything for most tapeworm infections, although it's important to discuss any new signs and symptoms, even if they're not related to the digestive tract. In the case of cysticercosis (infection with pork tapeworm), there’s the potential for cysts to form under the skin. A physician might be able to feel these cysts during a physical exam.

In the case of an infection with the beef tapeworm, Taenia saginata, it’s possible that eggs could be found during an examination of the perianal area (the skin around the anus). The eggs might be collected by applying a piece of cellophane tape to the perianal area. The eggs will stick to the tape, and the tape can be put on a slide for examination under a microscope.

Imaging

In the case of a pork tapeworm infection that has spread beyond the intestine and into other organs and body tissues, imaging tests might be needed to look for cysts and determine if there is any other damage.

Stool tests might not be positive for pork tapeworms in 50 percent or more of people who have cysticercosis. Two imaging tests that are often used to diagnose cysticercosis or neurocysticercosis in people that have symptoms of infection in the nervous system are computed tomography (CT) scan and magnetic resonance imaging (MRI).

CT Scan

A CT scan is a type of X-ray that is used to take images of the organs, tissues, and structures inside the body. The preparation for this test may include fasting for a few hours beforehand. Contrast dye may be given through an IV in order to better see certain parts of the body.

This test usually involves lying on a table that will slide into the CT machine. The machine will rotate around to take the images, and it will be important to stay still or hold your breath at times as instructed by a technician. 

MRI

An MRI is an imaging test that can be used to see structures inside the body, including the spine and the brain. It’s painless and non-invasive, although in some cases contrast dye may be given in an IV to get a better view of certain areas of the body.

Patients will lie on a table which slides into the MRI machine, which is a large tube. Earplugs or headphones may be offered as the machine may make a certain amount of noise.

Differential Diagnoses

Most people with a tapeworm infection don’t have symptoms, but if there are gastrointestinal symptoms such as diarrhea and abdominal pain, it may be necessary to rule out other digestive conditions such as:

• Appendicitis
• Enteritis (inflammation of the small intestine)
• Gallbladder inflammation
• Gastroenteritis
• Irritable bowel syndrome (IBS)

In the case of cysticercosis and neurocysticercosis (when the central nervous system is affected because the infection spread), it may be necessary to rule out conditions that could be causing symptoms in other areas of the body outside of the digestive tract and/or in the central nervous system, including:

• Brain abscess
• Encephalitis
• Epilepsy
• Meningitis
• Tumors 

Summary

The most common sign of a tapeworm infection is seeing a tapeworm in poop. Tapeworms like look like grains of rice and may be moving.

Tapeworm infections are diagnosed using a stool sample to analyze the type of tapeworm. In some cases, imaging studies may be needed to determine the extent of infection.  

If you see tapeworm in your poop, see your healthcare provider. Some tapeworm species can cause serious, long-term health problems.