Tapeworm infections in humans may take place in two ways:-
If ingested as eggs they can develop into larvae, these larvae can migrate out of the intestine and may reach other parts of the body like liver and lungs and form cysts in those tissues.
If ingested in the form of larvae then they grow into adult tapeworm in the intestine. Presence of tapeworms in the intestine is asymptomatic.
Infection by ingestion of tapeworm eggs is common with pork tapeworm (cysticercosis) and dog and sheep tapeworm (echinococcosis). Infection may be caused by ingestion of raw muscle tissues of infected animal.
There are several species of tapeworm that cause infection in humans:-
Hymenolepis nana (dwarf tapeworm), Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), Diphyllobothrium latum (fresh water fish tapeworm) are some of them. Infections of pork & beef tapeworms are the most common types in humans.
Inadequate hygiene, ingestion of raw food and improper sanitation facilities for human and animal feces are the risk factors for taeniasis.
Most of the cases of taeniasis are asymptomatic. If the symptoms are seen then they are nausea, loss of appetite, weight loss, abdominal pain, weakness, malabsorption and diarrhea. It's also possible to notice segments of the adult tapeworm (proglottids) in stool.
Some tapeworms attach to the intestinal lining and may cause inflammation and irritation.
However, if the larva has migrated out of the intestines and have formed cysts in some tissues there could be organ and tissue damage manifested as fever, allergic reaction (against larvae), bacterial infections, masses or lumps of cysts and neurological symptoms or seizures (if the larvae locate themselves in brain).
Taeniasis infection can be diagnosed by stool test (microscopic examination of stool). Tianiasis infection in the tissues can be diagnosed by blood test (detection of antibodies against the worm), CT (Computerized tomography) scan or MRI (Magnetic resonance imaging).
Medications used for the treatment of tapeworm infection belong to a category known as anti-helminthics like praziquantel, albendazole and niclosamide.
The choice of drug depends upon the species of infecting tapeworm and site of infection. In case of infection in various parts of body anti-inflammatory drugs are given to reduce swelling. Surgery and organ transplantation are also done in severe cases.
Pork tapeworm can migrate to tissues and parts of the body and grow there and interfere with the normal functioning of the organ. The condition is called as cysticercosis.
Pork tapeworm can also infect central nervous system and brain and cause neurocysticercosis characterized by headache, seizures, meningitis, dementia, visual impairment and death.
Sheep and dog tapeworm migrate to liver and develop into larvae. Due to the growth of these larvae there is a pressure on the adjacent blood vessels that obstructs the blood circulation. Surgery or liver transplantation is needed in severe cases.
There may be intestinal obstruction due to tapeworm infection.
