Hymenolepis nana ----------------------------- Taeniasis
Hymenolepis nana, The Dwarf Tapeworm
The Hymenolepis nana is also known as the Dwarf Tapeworm. There are 400 species of Hymenolepis. It is the
Hymenolepis nana that is known as the Human Tapeworm. Beetles and fleas are the intermediate hosts (the tapeworm
does not always need this host), and humans are both the primary and definitive hosts and can reinfect themselves.
Once the eggs are ingested they hatch, go through their larval stage in the small intestine, and then move into the
tissue in the gut and grow to adulthood. Hymenolepis nana infestations are prevalent in highly populated areas where
hygiene and sanitary conditions are poor.
Symptoms of the Hymenolepis nana are: anorexia, abdominal pain, and diarrhea, however, symptoms often go
Hymenolepis nana, -- Infection is most common in the Southeast (1% of school children in 1 study) and among
institutionalized children. Among more than 200,000 stool specimens submitted to the state laboratories in 1987 for ova
and parasite analysis, 0.4% were positive for H nana. Because most infections do not produce symptoms, the true
incidence is likely considerably higher.
The vast majority of infections produce no symptoms. Symptom frequency seems to correlate with increasing worm
burden. Among children with clinical infection, symptoms (in order of decreasing frequency) include restlessness,
irritability, diarrhea, abdominal pain, restless sleep, anal pruritus, and nasal pruritus. Rare symptoms include anorexia,
increased appetite, vomiting, nausea, bloody diarrhea, hives, extremity pain, headache, dizziness, behavioral
disturbances, and seizures
Taeniasis is a tapeworm infection
Teniasis; Pork tapeworm; Beef tapeworm; Tapeworm; Taenia saginata; Taenia solium
Tapeworm infestation does not usually cause any symptoms. Infection is generally recognized when the infected person
passes segments of proglottids in the stool, especially if the segment is moving.
self-infection with tapeworm eggs -- cysticercosis (T. solium only), which may cause seizures
rarely, worms may cause obstruction of the intestine
Taeniasis. Infection often is asymptomatic; however, mild gastrointestinal tract symptoms, such as nausea, diarrhea, and
pain, can occur. Tapeworm segments can be seen migrating from the anus or feces.
Cysticercosis. Manifestations depend on the location and numbers of pork tapeworm cysts (cysticerci) and the host
response. Cysts may be found anywhere in the body. The most common and serious manifestations are caused by
those in the central nervous system. Cysts of Taenia solium in the brain (neurocysticercosis) can cause seizures,
behavioral disturbances, obstructive hydrocephalus, and other neurologic signs and symptoms. Neurocysticercosis can
be a leading cause of epilepsy, depending on epidemiologic circumstances. The host reaction to degenerating cysts
can produce signs and symptoms of meningitis. Cysts in the spinal column can cause gait disturbance, pain, or
transverse myelitis. Subcutaneous cysts produce palpable nodules, and ocular involvement can cause visual impairment.
Produces only mild abdominal symptoms. Occasionally appendicitis or cholangitis can result from migrating proglottids.
Risk of development of cysticerosis with Taenia solium.
(Yanko 1988) Trichuris and Ascaris, Toxocara, Hymenolepis and Taenia (ascariasis was
estimated to affect four million people in the United States.)