Tuesday, September 18, 2012

Common Worm Infestations

Common worm infestations are medically termed helminthiasis. The word 'helminth' has been derived from the Greek word 'helm-in-thos' that means worm. The evolution of helminthiasis is as old as mankind. Helminths or worms are intestinal parasites and their prevalence is very high in developing countries. Over crowding in localities and deteriorating socio-economic conditions are the main cause of worm infestations/infections. Human beings have been documented as the reservoir for nematodes. Though some host-parasite relationships are relatively benign but almost all the worms are capable of causing serious pathological lesions leading to health complications. However, the population density of worms or intestinal helminths, influence their pathogenicity. We find that majority of the infected individuals are asymptomatic. Most of the intestinal helminths do not multiply within the human host.
There are two major groups of intestinal helminths or worms: A)  Nematodes and B)  Cestodes

A)    Nematodes
  1. The roundworm or Ascaris lumbricoides is the largest (15-35 cm in length) and most common nematode parasitizing the intestine of humans. The prevalence of roundworm infestation/infection is around 20% worldwide. Treatment with antihelminthics is effective to kill the adult roundworms but fails to kill larvae.
  2. Hookworm infestation/infection is common in all tropical and sub-tropical countries. Ancylostoma duodenale and Necator americana are predominant parasites. A single hookworm draws around 0.2 ml blood in 24 hours. Hookworm infestation may cause severe anemia. In such cases, effective means of treatment of anemia would be removal of hookworms by effective drugs before administration of treatment of anemia.
  3. The human whipworm, Trichuris trichuria is cosmopolitan in distribution. The whipworm may coexist with roundworm. Small children develop heavy infections due to autoinfection. Effective treatment of trichuriasis is available but self medication is not recommended.
  4. Other nematode infestations are Strongyloidiasis and Enterobiasis. Distribution of the intestinal parasites Strongyloides stercoralis and Enterobias vermicularis is worldwide. A number of drugs are available to give 100% cure.
B)    Cestodes (Tapeworm Infections)
The distribution of tapeworm infections is worldwide. Man serves as a definitive host for tapeworm species like Taenia saginata, Taenia solium and Hymenolepis nana. For Echinococcus granulousus, man serves as an intermediate host.

Prophylaxis for worm infestations:
  • Personal hygiene and sanitation is the chief method of control.
  • Administrative measures should be taken up to educate people on personal hygiene.
  • Mass treatment of the infected population with medically recommended safe and effective drugs.
  • Avoid eating raw vegetables.
  • Administrative measures to prevent contamination of drinking water and food stuffs.
  • Finger nails should be cut short and hands should be washed thoroughly with soap & water, after toilet and before meals.
  • Patient with enterobiasis should wash anal area immediately after waking up to avoid dispersal of eggs.
  • The infected person should be advised to sleep alone.
  • It is preferable to treat entire family if someone in the family has enterobiasis.