Intestinal
parasites
A parasite is an organism which lives at
the cost of end in the body of living organisms. Such parasites are found in
the intestine of human beings.
Intestinal parasites
|
Worm |
Lifecycle |
Features |
|
Round worm (Ascaris lumbricoides) |
The eggs are passed in stools.they are ingested with contaminated
raw vegetable. The worms come out of eggs in the intestine and pass through the
mucous membrane into the lymphatic system and from there into the blood
stream. From there they pass into the heart lungs,bronchi,trachea,oesophagus,
stomach and finally small intestine.There they attain adult state and the females start
laying eggs. |
These are long,tubular,and with tapering ends.They are reddish in
colour,and shine when alive.athe male is 3” to 10”long,while the female is
12”to14” long.The female lays several eggs in one day. The eggs do not cause
disease,but are spread through faeooral route and the worm causes disease.The
worms may get entangled in small intestinal lumen and cause intestinal
obstruction.They may pass into the stomach an be passed out by vomiting. |
|
Thread worm |
The female comes out of the anus at night and lays eggs in the skin
folds of the anus. Then it goes back into the rectum. The eggs are passed
into stools and contaminate fod.Ingestion of such food causes the eggs to
reach is perianal itching.duodenum,where they hatch. Then they become adult. |
These are thin like thread,0.5 cm to 1 cm long. They are visible
in recently passed stools.The male is half as long as the female,the worm is
found in the colon and rectum,stuck to the mucous membrane.There are eggs to
reach is perianal itching. |
|
Hook worm(Ankylostoma duodenale,Necator americanus) |
The female lays eggs which are passed into faeces and contaminated
food or hands. The eggs mix in soil.A larva forms after 5 days. It can
survive in that condition for several months. It survives better in moist and
warm soil,and less so in dry and hot surroundings.It enters human body
through cracks in skin of the foot while walking barefootin contaminated
soil.It causes local inflammation.It enters subcutaneous
tissue,lymphatics,lymph nodes,
veins,heart,lungs,bronchi,trachea,oesophagus,stomach and duodenum.There it
loses its covering and gets converted into adult form in 4 weeks. |
They are cylindrical,the male being 6mm to 10mm long,and the female being 6 mm
to 18 mm long. Ankylostoma duodenale is bigger than necator americanus and
has teeth.The latter has plates instead of teeth.The body is thread
like,while the head is conical.The mouth is round and has teeth or
plates,with which the worm adheres to the mucous membrane and sucks blood.It
causes pain in abdomen,anaemia, flatulence,constipation alternating with
diarrhoea. |
|
Tapeworm(Taenia saginata,taenia soleum) |
Ingestion of the It is found at all segments and ages. It is seen
in eggs by pigs or nonvegetarians. It cattle,resultsin caused by ingestion
their infection of improperly Ingestion of cooked undercooked meat
contaminated meat. Of these animals results in infection of the man. |
The worm has two suckers on its head with the help of which it
adheres to the mucosa of the intestine. The body is tape- like, made of
multiple segments.The patient gets pain in
abdomen,indigestion,anaemia,itching.around anus etc. |
Investigations
1.Examination of the stools shows the
worms.
2.Microscopic examination of the stools
shows the eggs of the worms.
Preventive
measure
1.Hands are washed well with soap and water
after defecation and also before eating food.
2.Files
are prevented from entering the house and sitting on food.
3.Cleanliness and hygiene is maintained in
and around the house.
4.Environmental sanitation is maintained.
5.Sanitary latrines are used.open air
defecation is avoided.
6.Uncooked vegetables, undercooked
vegetables and meat are not eaten.
Treatment
Anthelminthic Agents
|
Worm |
Drugs |
|
Round worm |
Piperazine citrate. Mebendazole. Albendazole. Pyrantel pamoate. |
|
Hook worm |
Mebendazole. Albendazole. PYrantel pamoate. |
|
Thread worm |
Mebendazole. Albendazole Pyrantel pamoate. |
|
Tape worm |
Niclosamide. Mepacrine. Dichlorophen. |
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