Nematodiasis is caused by the nematode wormHome | Contact Us | Sitemap | Login| Bookmark this site!   

NEMATODIASIS is caused by the nematode worm.


Ascariasis is caused by the largest nematode Ascaris lumbricoides (round worm).  It lives in the small intestine of man lying freely in the lumen.  Sexual dimorphism is well distinct; only sexual reproduction takes place.  Ascaris infection may be due to migrating larvae and by adult worms. The symptoms caused by the migrating larvae are fever, cough and dyspnoea. The symptoms caused due to adult worms are abdominal pain, vomiting, headache, irritability, dizziness and night terrors.


Ancylostomiasis is caused by two hook worms Ancylostoma duodenale and Nectar americus.  The adult worms live in the intestine of man particularly in the jejunum. Infection occurs when man walks bare foot on the faecally contaminated soil. It penetrates through the thin skin between toes, the dorsum of the feet and the inner side of the soles.  The characteristic symptoms of Ancylostomiasis are Ancylostome dermatitis or ground itch, gastrointestinal disorders and severe anemia by adult worms.


Enterobiasis is caused by Enterobius vermicualris commonly known as pin worm, thread worm, or seat worm.  The pinworm infection is more frequent in children than in adults. The symptoms include severe itching around the anus, loss of appetite, sleeplessness and sometimes inflammation in the vermiform appendix.


Trichuriasis is caused by Trichuris trichura, commonly known as whip worm.  The adult worms live in the large intestine of man, particularly in the caecum; also in vermiform appendix. The symptoms of the disease are acute appendicitis, mucus diarrhoea and abdominal pain.


Trichinosis is caused by Trichenella spiralis, the trichinia worm.  It is one of the smallest nematodes infecting man. Human becomes infected by eating undercooked raw meet containing cyst larvae mainly pork. Larvae mature to adult worms and attaches to the wall of small intestine. The early symptom of trichinosis is eosinophilia .the invasion of larva to the muscle is associated with muscle pain, swelling of the eyelids and facial oedema.


Strongyloidiasis is caused by the nematode Strongyloides stercoralis, commonly called thread worm. Parasitic pathogenic females live in the human small intestine and lay eggs in the mucosal epithelium releasing rhabditiform larvae .these larvae becomes infective filariform larvae. Larvae migrating through the lungs may provoke cough, haeomoptysis, and dyspnoea .severe infection of the intestine causes vomiting, diarrhoea and constipation.

Filariasis or Elephantiasis:

Filariasis is caused by Wuchereria bancrofti commonly called as filarial worm. The adult worms inhabit the lymphatic vessels, lymphatic nodes, testes and epididymis .The female worm discharges microfilariae that circulate in the blood. Humans are only definitive host. Insect vectors serve as intermediate host includes species of mosquito's .The infection of the filarial worm causes enlargement of the limbs, mammae and scrotum.


Loiasis is an infection caused by the filarial nematode Loa loa, the African eye worm or Loa worm. Humans and baboons are definitive host. The adult Loa worm migrates the skin and occasionally crosses the eye beneath the conjunctiva.  Ocular infections include swelling of lids, congestion, itching and pain.


Insects act as vectors in transmitting harmful parasitic infections .Important disease spreading insects are mosquitoes, flies, fleas, bugs, ticks, mites and lice.

Laboratory diagnosis:

Depending on the nature of the parasitic infections, the following materials should be collected:
  1. Blood:  where the parasite itself or any stages of development circulates in the blood stream. Examination of blood film forms one of the main procedures for diagnosis For eg .In malaria, the parasites are found inside the erythrocytes.
  2. Stool:  Examination of stool forms an important part in diagnosis of intestinal parasitic infections and also Helminth parasites .In protozoal infection, either trophozoites or cystic forms may be detected. In helmithic infection, either the adult worm or their eggs are found.
  3. Urine: when the parasite lives in the urinary tract ,examination of urine can diagnose the infection.
  4. Sputum: Examination of sputum will be useful and important if the parasite localizes in the respiratory tract.
  5. Biopsy material: spleen puncture, bone marrow puncture, skin biopsy, muscle biopsy, rectal biopsy, liver biopsy, lumbar puncture
  6. Indirect evidences: Changes indicative of internal parasitic infection are
    1. Cytological changes in the blood
    2. Biochemical alteration of the blood
    3. Serological tests
    4. Intradermal reaction test


  • Therapeutic Prophylaxis: The parasite is attacked with in the host, there by preventing the dissemination of the infective agents.
  • Eradication of the infection in the reservoir hosts and destruction of intermediary hosts.
  • Personal prophylaxis may be further ensured.
Diagnostic Procedures | Helminths | Introduction to parasitology | Medical Parasitology | Protozoology