What is the morphology of Hymenolepis nana?
Morphology of Hymenolepis nana It is small and thread like worms measuring 1-4 cm in length with a diameter of 1mm. Body consists of a scolex, a long neck and strobili consists of nearly 200 proglolttids. The size of the storbila is usually inversely proportional to the number of worms present in the hosts.
What is a major morphological difference between hymenolepis Diminuta and Hymenolepis nana?
H. diminuta may be distinguished from R. nana by its greater size, being 20 to 60 mm in length and 3 to 4 mm in width; and its having a small pear-shaped scolex bearing four deep suckers with an unarmed rostellum Fig. 13-11).
What is the intermediate host for hymenolepis Diminuta?
Arthropods, especially beetles, serve as intermediate hosts for Hymenolepis spp. The arthropod intermediate host is required for H. diminuta, but not H. nana, and humans can become infected with the latter by direct ingestion of eggs.
What type of organism is Hymenolepis nana?
Dwarf tapeworm (Hymenolepis nana, also known as Rodentolepis nana, Vampirolepis nana, Hymenolepis fraterna, and Taenia nana) is a cosmopolitan species though most common in temperate zones, and is one of the most common cestodes (a type of intestinal worm or helminth) infecting humans, especially children.
What is the infective stage of hymenolepis Diminuta?
Hymenolepis diminuta is a cestode of rodents infrequently seen in humans and frequently found in rodents. Eggs of Hymenolepis nana are immediately infective when passed with the stool and cannot survive more than 10 days in the external environment .
What is the infective form of hymenolepis Nana?
The cestode, Hymenolepis nana, also called the dwarf tapeworm, causes hymenolepiasis, which is usually asymptomatic. Some weakness, headache, anorexia, and abdominal pain may occur. When passed in the stool, the eggs are infective and are ingested by beetles or flies, which serve as intermediary hosts.
Can hymenolepis Diminuta cause Autoinfection?
About 20 to 30 days after initial ingestion, the worm begins to shed eggs in the stool. H. nana adults live for only 4 to 6 weeks, but eggs shed in the stool are immediately infective. Self-inoculation or internal autoinfection allows colonization to persist for years.
What is the larval stage of Hymenolepis Nana?
Hymenolepis nana is unique among tapeworms in that the adult worm develops after the egg is ingested. The hooked oncosphere then invades the intestinal mucosa and develops into a cysticeroid larva.
What is the common name for hymenolepis Diminuta?
Map to
| Mnemonic i | HYMDI |
|---|---|
| Common name i | Rat tapeworm |
| Synonym i | – |
| Other names i | ›Hymenolepsis diminuta |
| Rank i | SPECIES |
What cestode causes Autoinfection?
H. nana (dwarf tapeworm) is the smallest but most common tapeworm that colonizes people. It can be transmitted directly from person to person. Self-inoculation or internal auto-infection permits accumulation of a large number of worms that can cause anorexia, abdominal pain, and diarrhea.
What is the name of the encysted larva for H Diminuta?
Once in the intestine, the eggs hatch to form oncospheres, which penetrate the mucosa to encyst as cysticercoid larvae. Four or 5 days later, the larval cyst ruptures into the lumen to form the relatively small, adult H. nana tapeworm (15 to 50 mm in length).
What is the size of Hymenolepis diminuta?
Adult Hymenolepis diminuta reach 20 to 60 cm, and up to 90 cm . The cestode has a long cylindrical body with 4 suckers and an apical organ at its scolex with no rostellar hooks. Hymenolepis diminuta, along with all cestodes, lacks any trace of a digestive tract, and it absorbs all required substances through its external covering.
What is the pathophysiology of hymenolepiasis?
Hymenolepiasis is caused by two cestodes (tapeworm) species, Hymenolepis nana (the dwarf tapeworm, adults measuring 15 to 40 mm in length) and Hymenolepis diminuta (rat tapeworm, adults measuring 20 to 60 cm in length). Hymenolepis diminuta is a cestode of rodents infrequently seen in humans and frequently found in rodents.
What is the size of a Hymenolepis egg?
Eggs of Hymenolepis diminuta. These eggs are round or slightly oval, size 70 – 85 µm X 60 – 80 µm, with a striated outer membrane and a thin inner membrane. The space between the membranes is smooth or faintly granular.
What are the signs and symptoms of Hymenolepis nana?
Hymenolepis nana and H. diminuta infections are most often asymptomatic. Heavy infections with H. nana can cause weakness, headaches, anorexia, abdominal pain, and diarrhea. Hymenolepis diminuta eggs in wet mounts.