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In this article we will discuss about Hymenolepis Nana.
Morphology of Hymenolepis Nana:
H. nana (Fig. 107.21) is a cosmopolitan parasite. It is small and measures up to 25-40 mm in length by one mm in diameter. Its scolex (Fig. 107.22) is minute, rhomboidal and has four suckers and a short rectractile rostellum armed with 20-30 hooklets in one single row.
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The rostellar hooklets are shaped like tuning forks and its neck is long and its segments (Fig. 107.23) are about 200. It egg is spherical, contains an oncosphere enclosed in an inner envelope with two polar thickenings from which polar filaments (Fig. 107.24).
Life Cycle of Hymenolepis Nana:
When fully embryonated eggs in human faeces are ingested by man, only one host, they hatch in the intestine, then the free oncospheres penetrate into the villi of the small intestine and metamorphose into young cercocysts or cysticercoids (larvae, Fig. 107.25) which migrate into the lumen, become attached by their scolices to the small intestine and develop into mature worms which lay eggs.
Clinical Features of Hymenolepis Nana:
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There is generalized toxaemia due to absorption of the metabolic wastes of the parasite. The general symptoms are headache, dizziness, anorexia, pruritus of nose and anus, periodic diarrhoea and abdominal pain.
In the Laboratory, the characteristic eggs can be demonstrated microscopically in the patient’s stool.
Treatment of Hymenolepis Nana:
Niclosamide, Hexylresorcinol crystalloid. Quinacrine and Mebendazole are very effective.
Prophylaxis:
This comprises:
1. Avoidance of ingestion of eggs, through contaminated food or drink. Contamination may occur from toilet seats, soiled linen or directly from anus to mouth.
2. Personal hygiene and
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3. A well balanced diet which reduces susceptibility to infection.
