Today is our topic of discussion General characteristics of helminthes
General characteristics of helminthes
1. They do not possess organs of locomotion, so locomotion is by muscular contraction & relaxation.
2. The outer covering is called cuticle or integument; it is resistant to intestinal digestion and may be armed with spines or hooks.
3. Nervous system and excretory system are primitive. IT (AM) andhom soone
4. Digestive system is complete, partially lost (rudimentary) or absent; entirely disappeared in tapeworms (cestodes); greatly or nearly absent in many of the trematodes; complete in most nematodes.
5. Reproductive system is well developed.
6. Both self-fertilization and cross-fertilization may take place.
10. The co-existence of several species of helminths in the same individual (poly-helminthism) is widely prevalent.
11. In some helminths, the life cycle is direct & relatively simple; involving only one host species and a brief period of development of an infective stage. Example – pin worm (Enterobius vermicularis).
12. Worms & larvae that migrate through or reside in tissue generally produce eosinophilia, focally in tissue, in the blood or in both.
Classification of helminths:
1. Cestodea (tapeworm)
2. Trematodea (fluke)
3. Nematodea (roundworm and threadworm).
Common features of nematode:
1. Cylindrical body shape and do indeed have a body cavity.
2. Its body covering is a cuticle and the digestive tube ends in the anus.
3. The sex of nematodes has distinct male and female pattern.
4. Their attachment organs range from lips, teeth, filariform extremities and dentary plates.
Helminthiasis:
A disease that is caused by infestation with parasitic worms.
Helminthic diseases common in Bangladesh:
Hookworm disease (ankylostomiasis), ascariasis, enterobiasis, strongyloidiasis, trichuriasis and taeniasis.
Soil-transmitted helminths:
Soil-transmitted helminths refer to the intestinal worms infecting humans that are transmitted through contaminated soil. These are –
1. Ascaris lumbricoides
2. Whipworm (Trichuris trichiura)
3. Hookworm (Ankylostoma duodenale and Necator americanus)
[ Note: Arise of complications in any of helminthic infestation (helminthic crisis) usually an indication for the referral of the case. In a state of helminthic crisis, anti-helminthic medications are usually avoided. After subside of the acute state, medications may be given. Most of the helminthic crisis is managed conservatively; a few may require surgical intervention ]
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