The document provides a detailed overview of intestinal nematodes, focusing on their characteristics, life cycles, and specific types like Ascaris lumbricoides and Ancylostoma duodenale. It discusses their morphology, modes of transmission, clinical features, laboratory diagnosis, treatment, and preventive measures. Nematodes are described as thread-like structures with separate sexes, and the document highlights the prevalence of these infections, particularly in underdeveloped regions.

1. INTESTINAL NEMATODES
By- Dr. Manish Tiwari
Mail – mprabhat111@gmail.com

2. INTESTINAL NEMATODES
CHARACTERISTICS
 It belongs to phylum Nemathelminthes.
 They are elongated, cylindrical, bilaterally symmetrical.
 Unsegmented worm with tapering ends.
 The nematode means thread like structure.
 It has no suckers, no hooks.
 Body cavity is present.

3.  Body is covered with tough cuticle.
 Sexes are separate.
 Male is generally smaller than female.
 Fertilization is internal.
 They pass their life cycle in one host except filarial
nematode.

4. DIVISION OF FEMALE NEMATODE
1. Oviparous – Nematode which lay eggs.
 un-segmented egg (Ascaris lumbricoides)
 segmented egg (Hook worms)
1. Viviparous - Nematode which give the birth to
larvae.(W. bancrofti, B. malayi)
2. Ovo-viviparous – lay eggs containing
larvae.(strongyloides stercoralis)

5. CON……
Small intestine Large intestine
 Ascaris lumbricoides
 A. duodenale
 N. americanus
 T. spiralis
 Capillaria Spp.
 Enterobius vermicularis
 Trichuris trichiura

6. ASCARIS LUMBRICOIDES
1. INTRODUCTION
2. GENERAL CHARACTERISTICS
3. MORPHOLOGY
4. EGGS
5. LIFE CYCLE
6. CLINICAL PRESENTATION
7. LAB DIAGNOSIS
8. TREATMENT
9. PROPHYLAXIS

7. 1.INTRODUCTION
 Most common helminthic human infection.
 Largest nematode to infect the human intestine.
 High prevalence in underdeveloped countries.
 It is estimated that ˃250 million people worldwide are
infected by this parasite
 It has simple life cycle.

8. . GENERAL
CHARACTERISTICS
 Family is ascaridae.
 Common name roundworm.
 Infective stage is embryonated egg containing
rhabditiform larva.
 Habitat small intestine particularly the jejunum of
man.

9. Morphology of worm
 The body of ascaris is cylindrical , tapering end.
 Posterior end of male worm is curved ventrally.
 The mouth opens at the anterior end.
 It contain three finely toothed lips, one dorsal & two
ventral.
 Female is larger in size and measure 25-40cm.

10. MALE & FEMALE
MALE WORM
 It measure 15-30cm in length & 3-4 mm diameter.
 The posterior end is curved ventrally to form a
hook.
FEMALE WORM
 It is longer and stouter than the male worm.
 It measure 25 -40 cm in length & 5 mm in diameter.
 the anus is subterminal.
 Tail is straight & conical.
 Valva open at the junction of anterior and middle 3
rd of the body

11. 4. EGGS

12. 5. LIFE CYCLE
 The life cycle of A. lumbricoides is passed in only one host
(man).
 No intermediate host is required.
 Worm reside in the small intestine
 Fertilized eggs contain unsegmented ova which are passed
faeces in the soil.
 Rhabditiform larva developed from unsegmented ovum.

13. Adult worm in intestine
Eggs released in faeces
Developed to infective stage in soil
Eggs ingested and hatched
Larva penetrate intestinal wall
Migrate to blood stream

14. Heart
Alveoli of lungs
Trachea and larynx
Pharynx
Swallowed
Then form adult worm

15. 6. CLINICAL FEATURES

17. 7. LABORATORY DIAGNOSIS
 Macroscopic examination
Adult worm passed though anus, mouth, nose, ear.
 Demonstration of larvae
Detection in sputum during larvaal migration.
 Stool microscopy
Identification of fertilized and un-fertilized eggs.

18.  Serodiagnosis
Ascaris antibody can be detected By indirect
immunofluorescence test(IFA), indirect
haemagglutination assay (IHA).
 Eosinophilia
During the larval migration.

19. 8. TREATMENT
Albendazole 400mg : single dose
Mebendazole 100mg : twice daily for 3 days
Pyrantel pamoate
piperazine

20. 9. PROPHYLAXIS
Proper disposal of human faeces
Avoidance of eating raw vegetables and salads.
Periodic treatment with an effective anthelminthic, in
communities that lack sanitization facilities.

21. ANCYLOSTOMA
DUODENALE
 Old world hook worm
 Habitat – small intestine in man particularly in the
jejunum and rarely in duodenum & ileum.
 Remain attached to the intestinal wall.
 Ancylostomiasis

22. DIFFERENCE BETWEEN A.DUODENALE& N. AMERICANUS.
A. DUODENALE N. AMERICANUS
 Old world hook worm
 Anterior end bends in same direction.
 Six teeth, four on ventral surface &
two on dorsal.
 Larger & thicker.
 More pathogenic.
 New world hook worm.
 Anterior end bends in opposite
direction.
 Four cutting plates, two each on
ventral & dorsal.
 Smaller & thinner.
 Less pathogenic.

23. Morphology of adult worm
They are small , pinkish & fusiform in
shape
 The anterior end is curved dorsally ,
hence the name hookworm.
 The oral cavity provide four hook
like teeth on the ventral surface and two
knob like teeth on dorsal surface.
 Adult worm are rarely seen , because
they attached to the intestinal mucosa.

24. MORPHOLOGY OF EGG
Oval and measure 60 x 40µm.
 Non bile stained.
 Surrounded by thin shell.
 Posses a segmented ova with usually four
blastomeres.
 There is clear space between ovam & egg
shell.
 The egg float in saturated in salt solution
 Eggs are normally released in faeces after 3
– 4 weeks of infection.

25. TRANSMISSION
 Penetration of skin.
 Ingestion of larva.
 Trans-placental transmission.

26. LIFE CYCLE
 Human are the only natural host.
 Adult worm lives in small intestine.
 Eggs passed in feaces.
 Rhabditiform larvae hatch out from the egg in the soil.
 Grows in size by feeding on bacteria and organic matter.
 Third larval stage is filariform larva.

27.  When a person walk barefooted, they penetrate the
skin.
 Larvae enter the venules and reaches right heart and
lungs.
 Crawl over epiglottis to pharynx and are swallowed.
 Get matured and life cycle completed.

28. Adult worm reside in intestine
Eggs discharge in faeces
hatch in soil
Rhabditiform larva developed (non infective)
Filariform larva developed ( infective stage)
Then penetrate skin

29. Migrate via blood stream
Heart & Lungs of alveoli
Trachea & larynx, pharynx
Swallowed
Adult worms in intestine

31. DERMATITIS OR GROUND ITCH
Larvae enter the skin, may lead
to dermatitis.
Intense itching, burning and
develop erythema and oedema.

32. RESPIRATORY
MANIFESTATION
Low grade fever.
Cough.
Dyspnea.
Pneumonia with pulmonary consolidation.
Bronchitis.

33. INTESTINAL MANIFESTION
Low grade fever
Iron deficiency anaemia (hookworm ingest blood)
Nausea
Vomiting
Diarrhea
Abdominal discomfort

34. DIAGNOSIS
Stool examination:
detection of egg and adult
worm.
Blood examination may
reveal microcytic,
hypochromic anaemia.
Occult blood test.

35. TREATMENT
 Mebendazole
 Thiabendazole
 Treatment of iron deficiency anaemia with
replacement iron therapy.
 Folic acid and vitamin B12.

36. ENTEROBIUS VERMICULARIS
1. GENERAL CHARACTERISTICS
2. MORPHOLOGY
3. EGG OF E. VERMICULARIS
4. LIFE CYCLE
5. CLINICAL FEATURE
6. LAB DIAGNOSIS
7. TREATMENT

37. GENERAL CHARACTERISTICS
 Common name - Pin worm , Thread worm and seat
worm
 Habitat - Caecum, appendix
 Infective stage - Embryonated egg

38. MORPHOLOGY

39. EGG OF E.VERMICULARIS
Eggs are colourless.
Non bile stained.
Flattened on one side.
Measure 60µm.
Surrounded by thin shell

40. LIFE CYCLE
 Infection known as enterobiosis.
 It completed in a single host(human).
 Infection occur by ingesting egg.
 Larvae hatch from the egg in the small intestine.
 Male fertilize female and dies.
 Individual may develop autoinfection.

41. Life Cycle

42. CLINICAL PRESENTATION
 The clinical feature of pinworm infection, also called
enterobiasis, includes:-
 itching or prickling pain in the anal area (usually at
night time or in the early morning), intense anal
itching,
 difficulty sleeping,
 rarely abdominal discomfort
 loss of appetite.

43. PATHOGENICITY
 Pin worm infection most frequent in school age
children.
 Children suffering sleepless night due to itching at the
perianal region.
 May show irritability, enuresis and weight loss.
 Scratching predispose to secondry bacterial infection.

44. LABORATORY DIAGNOSIS
1. Detection of adult worm: may be
detected in the perianal region or at the
surface of stool.
2. Demonstration of egg:
Egg not discharge into faeces.
Non bile stained & flattened on one
side
It is contain fully developed larva.
NIH swab
3. No serological test are available.

45. SWAB

46. Scotch tape method

47. TREATMENT
 Mebendazole 100mg in single dose, And repeat after
2 weeks
 Albendazole 400mg in single dose, repeat after 2
weeks.

48. CUTANEOUS LARVA MIGRANS(CLM)
1. INTRODUCTION
2. CAUSATIVE AGENT
3. GEOGRAPHICAL DISTRIBUTION
4. RISK FACTOR
5. LIFE CYCLE
6. CLINICAL FEATURES

49. INTRODUCTION
 Cutaneous larva migrans (CLM) is a parasitic skin infection.
 It is caused by hook worm larva that usually infect the cats,
dogs and other animals.
 Human can be infected with the larva by walking barefoot
on soft soil has been contaminated with animal faeces.
 It is also called creeping eruption.

50. 2. CAUSATIVE AGENT
 There are many types of hook worm can causes cutaneous larva migran.
 It is caused by:
1. Ankylostoma braziliense: it is hookworm of wild and domestic dogs and
cats
2. Ankylostoma caninum: it dog hookworm that found in australia.
3. Uncinaria stenocephala: it is alo dog hookworm that found in europe.
4. Bunostomum phlebotomum: it is cattle hookworm.

51.  NOTE:- it is also caused by ankylostoma duodenale,
nector americanus and strongyloides sterocalis.
3. GEOGRAPHICAL DISTRIBUTION:- it is most
commonly found in the tropical and subtropical country .
 RISK FACTOR:- People of all ages and sex can be
affected by cutaneous larva migrans if they have been
exposed to hookworm larvae.
 Groups at risk include those with occupations or hobbies
that contact with warm, moist, sandy soil. These may
include:

52.  Barefoot beachcombers and sunbathers
 Children in sandpits
 Farmers
 Gardeners
 Plumbers
 Hunters
 Electricians
 Carpenters
 Pest exterminators.

54. CLINICAL FEATURES

58. TREATMENT
 Anthelmintics such as thiabendazole, albendazole,
mebendazole and ivermectin are used.