About Human Tapeworm

Overview

Taeniasis in humans is a parasitic infection caused by the tapeworm species Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and Taenia asiatica (Asian tapeworm). Humans can become infected with these tapeworms by eating raw or undercooked beef (T. saginata) or pork (T. solium and T. asiatica). People with taeniasis may not know they have a tapeworm infection because symptoms are usually mild or nonexistent.

T. solium tapeworm infections can lead to cysticercosis, which is a disease that can cause seizures, so it is important seek treatment.

Species

Taeniasis in humans is a parasitic infection caused by these tapeworm species

• Taenia saginata (beef tapeworm)
• Taenia solium (pork tapeworm)
• Taenia asiatica (Asian tapeworm)

Taenia saginata and T. solium are found worldwide. Infections with T. saginata occur wherever contaminated raw beef is eaten, particularly in Eastern Europe, Russia, eastern Africa and Latin America. Taeniasis due to T. saginata is rare in the United States, except in places where cattle and people are concentrated and sanitation is poor, such as around feed lots where cattle can be exposed to human feces. Tapeworm infections due to T. solium are more prevalent in under-developed communities with poor sanitation and where people eat raw or undercooked pork. Higher rates of illness have been seen in people in Latin America, Eastern Europe, sub-Saharan Africa, India, and Asia. Taenia solium taeniasis is seen in the United States, typically among Latin American immigrants. Taenia asiatica is limited to Asia and is seen mostly in the Republic of Korea, China, Taiwan, Indonesia, and Thailand.

Symptoms

Most people with tapeworm infections have no symptoms or mild symptoms. Patients with T. saginata taeniasis often experience more symptoms that those with T. solium or T. asiatica infections because the T. saginata tapeworm is larger in size (up to 10 meters (m)) than the other two tapeworms (usually 3 m). Tapeworms can cause digestive problems including abdominal pain, loss of appetite, weight loss, and upset stomach. The most visible sign of taeniasis is the active passing of proglottids (tapeworm segments) through the anus and in the feces. In rare cases, tapeworm segments become lodged in the appendix, or the bile and pancreatic ducts.

Taenia saginata does not cause cysticercosis in humans. It is not clear if T. asiatica causes cysticercosis in humans or not.

Causes and spread

Eating raw or undercooked contaminated beef or pork is the primary risk factor for acquiring taeniasis. Because of this, certain groups with dietary restrictions for these meats may have a lower risk of taeniasis.

A disease called cysticercosis can occur when T. solium tapeworm eggs are ingested. For example, people with poor hygiene who have taeniasis—with or without symptoms—will shed tapeworm eggs in their feces and might accidentally contaminate their environment. This can lead to transmission of cysticercosis to themselves or others unknowingly.

Prevention

One way to prevent taeniasis is to cook meat to safe temperatures. A food thermometer should be used to measure the internal temperature of cooked meat. Do not sample meat until it is cooked. USDA recommends the following for meat preparation.

For Whole Cuts of Meat (excluding poultry)

Cook to at least 145° F (63° C) as measured with a food thermometer placed in the thickest part of the meat, then allow the meat to rest* for three minutes before carving or consuming.

For Ground Meat (excluding poultry)

Cook to at least 160° F (71° C); ground meats do not require a rest* time.

*According to USDA, "A 'rest time' is the amount of time the product remains at the final temperature, after it has been removed from a grill, oven, or other heat source. During the three minutes after meat is removed from the heat source, its temperature remains constant or continues to rise, which destroys pathogens."

Testing and diagnosis

Diagnosis of Taenia tapeworm infections is made by examination of stool samples; individuals should also be asked if they have passed tapeworm segments. Stool specimens should be collected on three different days and examined in the lab for Taenia eggs using a microscope. Tapeworm eggs can be detected in the stool 2 – 3 months after the tapeworm infection is established.

Tapeworm eggs of T. solium can also infect humans, causing cysticercosis. It is important to diagnose and treat all tapeworm infections.

Treatment

Treatment is available after accurate diagnosis. Praziquantel is the drug of choice. Niclosamide is an alternative drug. See your healthcare provider for proper treatment and care.

Animal transmission

The tapeworm that your pet was diagnosed with is more than likely the flea tapeworm (Dipylidium caninum). Dog or cat tapeworm infections are a result of your pet swallowing a parasite-contaminated flea. Only in very rare instances do humans accidentally swallow the contaminated fleas.