The document discusses several types of parasitic nematodes (roundworms) that infect humans, including Ascaris lumbricoides (the large roundworm), hookworms, Enterobius vermicularis (pinworm), Guinea worms, and Trichinella spiralis (trichina worm). It describes the life cycles, modes of transmission, symptoms, treatment and prevention of infections caused by these parasites.

1. CYLINDRICAL WORLD
BY hasan askari BDS RDS MS
MUHAMMAD BIN QASIM MEDICAL
AND DENTAL COLLEGE
KARACHI
 SCRIPT BY: DR HASAN ASKARI
 DIRECTED BY: DR HASAN ASKARI
 PRODUCED BY:DR HASAN
ASKARI

2. Phylum Nematoda
 Nematodes (from Greek nema a thread) are
long, thin often threadlike “worms”.
 The head is small and possesses only small
sense organs and the overall appearance is of
an organism that narrows at both ends.

3. http://www.ucmp.berkeley.edu/phyla/ecdys
ozoa/nematoda.html
1 mm long nematode

4. Phylum Nematoda
 The nematodes are quite species diverse
(about 15,000 species.
 Most nematodes are under 5cm and many are
microscopic.

5. Phylum Nematoda
 Nematodes use their pseudocoelom as a
hydrostatic skeleton. Fliud filled cavity
 The body has a thick cuticle (made primarily of
collagen) secreted by the underlying epidermis,
which resists the high hydrostatic pressure
exerted by the fluid in the pseudocoelom.

6. Phylum Nematoda
 Beneath the epidermis is a layer of longitudinal muscles.
 Muscles in nematodes are not arranged in antagonistic
pairs, the antagonistic role is played by the cuticle.
 Contraction of a longitudinal muscle on one side is
transmitted through the hydrostatic skeleton and
stretches the cuticle on the opposite side of the body.
 When the muscle relaxes, the cuticle contracts and the
body returns to its resting position.

7. Phylum Nematoda
 Nematodes have a complete gut with a mouth,
muscular pharynx, intestine, rectum, and anus.
 Most nematodes males are smaller than females.
Mail have tail.
 Fertilization is internal and juveniles go through
several developmental stages, each time molting
or shedding their cuticle.

8. Free-living nematodes
 Free-living nematodes live in the sea, in fresh
water, and in the soil. They occur worldwide in all
environments and most live in the interstitial
spaces of sediments and soils.

9. Free-living nematode
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg8.htm

10. Free-living nematodes
 Most free-living nematodes are carnivorous.
 However, some feed on algae and fungi
,plants, especially the roots.

11. Free-living nematodes
 Many root feeding nematodes are major
agricultural pests. These species pierce root
cells and suck out their contents.
 Nematodes are estimated to destroy 12% of
the world’s cash crops annually.

12. Parasitic nematodes
 There are a great many species of parasitic
nematodes and they attack virtually all
groups of animals and plants.
 Parasitic forms include ascarids, hookworms,
Guinea worms, trichina worms, pinworms,
and filarial worms.

14. Ascaris lumbricoides: large
roundworm of humans
 It’s estimated that worldwide as many as 1.4
billion people are infected with Ascaris
lumbricoides which lives in the small intestine.
 Females may be a foot long and produce
200,000 eggs a day.
 Infection occurs when parasite eggs are eaten
with uncooked food or when soiled fingers are
put into the mouth.

15. ascaris
 Disease: ASCARASIS
 Pathogensis and clinical findings:
 Larval migration is most lethal than presence
of worm in intestine.
 Mostly affect lungs.
 Inflammation with an eosinophilic exduate .
 Usually children.
 Infection are asymptomatic.
 Ascaris pneumonia (fever,cough,abdominal
pain and even intestinal obstruction.

17. ascaris
 Epideminlogy common disease in tropics.
 Laboratory diagonsis egg in stool oval
irregular surface.
 Treatment mebendazole and pyrantel
pamoate
 Prevention proper disposal of feces

18. Ascaris lumbricoides: large
roundworm of humans
 The ingestion of worm eggs via food and
water contaminated with human feces .these
eggs hatch in small intestinal wall and travel
through the blood stream to the lungs where
they break out of the alveoli (often causing
pneumonia).
 Then they make their way up the trachea
where they are swallowed and eventually
settle in the small intestine.

19. Ascaris lumbricoides: large
roundworm of humans
 In the intestines the worms cause abdominal
symptoms and allergic reactions and may
produce an intestinal blockage.

20. life cycle of ASCARIS

21. 9.8
Figure 15.05a
Male (top) and female Ascaris lumbricoides

23. Hookworms Nector (NEW
WORLD) and ancylostoma
 Hookworms are named for the dorsal curve in
their anterior end.
 Hookworms are quite small, the commonest
species Necator americanus is only 11mm
long. However, because they feed on blood a
heavy infection can produce severe anemia.

24. http://www.virginmedia.com/images/hookworm.jpg

25. Hookworms
 Large plates in the hookworm’s mouth are used
to cut the intestinal lining of the host.
 The parasite then pumps blood through its gut,
partially digesting it before excreting it.
 Because hookworms suck more blood than they
use, they can cause debilitating anemia. In
children a hookworm infection can stunt growth
and cause a general lack of energy.

26. 9.9
Figure 15.06
Section through hookworm
attached to dog intestine

27. Hookworms
 Hookworms do not permanently attach in
one spot, but move around the gut and
reattach when they are ready to feed.
 Hookworms have evolved sophisticated anti-
clotting factors that keep platelets from
clumping and forming a clot while the
hookworm is feeding.

28. Hookworms
 Pathogensis and clinical finding excess loss of
blood from intestine.
 0.1 to 0.3 mL/day
 Weakness and pallor may leads to
microcystic anemia due to blood loss.
 Ground itch vesicles at site of entry of larva
 Pneumonia and eosinophilia at larval
migration.

29. Hook worm
 Epidemiology tropical area.
 Prediposing factor Walking barefooted on
soil
 Labortory diagonsis
 Eggs in stool ,ocult blood in stool ,eosinophil.
 Treatment mebendazole and pyrantel
pamoate
 Prevention sewage properly and wear shoes

31. Hookworms
 The life cycle of hookworms is similar to that
of ascarids.
 Infection occurs after a larva hatches from an
egg and penetrates the skin of a person. It
then makes its way to the lungs where
eventually it is coughed up and swallowed
and travels to the intestines.

32. Hookworm life cycle

34. ENTEROBIUS VERMICULARIS
Pin worm
 Disease pinworm infection enterobiasis
 Pathogensis and clinical finding effected site
perianal pruritus .
 Epidemiology common in tropical
 chidren younger than 12 years.

35.  Labortory diagonsis
 Eggs recovered from peroanal skin by using
scotch tape techniques.
 There eggs are not found in stool.
 Small white adult found in the stoolnear anus
of diapered children.
 Treatment mebendazole or pyrantel
pamoate.
 Prevention no mean

37.  Infection in human no animal involve.
 Iinfection by ingestion the worm eggs in small
intestine then change to larvae in colon.
 Male female meet at colon .
 In night female migrates from anus and
reseales thousands of fertilized eggs on the
perianal skin .

39. Guinea worms
 Guinea worm infections (also referred to as
Dracunculiasis) are now confined to sub-Saharan
Africa.
 Humans become infected when they drink water
containing the crustaceans.

40. Guinea worms
 The immature worm penetrates the gut wall
and wanders through the body, maturing and
growing.
 After about a year the female makes her way
to the surface of the skin (usually in the legs)
causing very painful blistering.

41. Guinea worms
 To ease the pain, sufferers immerse their feet
in water. This bursts the blisters and the
female worm then protrudes from the sore
and lays her eggs, thus continuing the life
cycle.

42. Guinea worms
 There is no cure for Guinea worms and the
only way to remove one is to slowly over the
course of weeks wind the worm out on a
stick.
 If the worm breaks,
a serious bacterial
infection results.

44. Interestingly, the traditional symbols for medicine
and healing the staff of Asclepias (showing a
snake entwined around a staff) and the caduceus
(which shows two snakes entwined about
a winged staff) very likely are derived from the
Guinea worm removal technique.

45. Guinea worms
 Guinea worm infection is avoidable with
relatively simple precautions such as
preventing people walking in drinking water
sources and boiling or filtering water before
drinking it.

46. Guinea worms
 Since the mid 1980’s a campaign to eradicate
Guinea worms coordinated by the U.N. and
the Carter Center has had tremendous
success.
 In 1986, an estimated 3.5 million people were
infected, but by 2000 the number of cases
had been reduced to about 75,000 and by
2006 to 11,000.

47. Guinea worms
 Guinea worms have been eliminated from
Pakistan, India, and Iran and infections
greatly reduced over much of sub-Saharan
Africa.
 The major barrier to elimination at this point
is the ongoing conflict in southern Sudan
where the majority of cases now occur.

48. Guinea worms
 The Carter Center and the fight against
Guinea worms. (4 minutes)
 http://www.youtube.com/watch?
v=u4kQWvUv_Ns

49. 9.12
Figure 15.11
Elephantiasis of leg
caused by filarial worms

50. Trichina worms
 Trichinella spiralis is a tiny nematode that causes
the potentially fatal disease trichinosis.
 Humans typically become infected by eating
undercooked pork. Trichinella lives in cysts
formed in individual muscle cells of the host.
http://en.wikipedia.org/wiki/File:Trichinella_larv1_DPDx.JPG

51. Trichina worms
 Trichinella when it hatches from an ingested cyst
in its host’s gut drills through the wall of the gut
where females produce living young.
 These juveniles travels in the circulatory system
to a muscle.
 The juvenile penetrates an individual muscle cell
and breaks the cell down so it can be remade.

52. Trichina worms
 Trichinella, just as a virus does, manipulates the
host cell’s DNA. It causes the cell to recruit a
blood supply to supply food to the cell and also
produce collagen to form a cyst around the cell.
 The Trichinella juvenile awaits ingestion by
another host. When ingested it emerges from its
cysts enters the mucosal lining of gut, develops
into an adult and continues the life cycle.

53. Trichinella life cycle in humans
http://www.trichinella.org/bio_lifecycle.htm

54. Trichina worms
 Adults usually do not persist long in the gut
before being expelled by the host’s immune
system.
 Trichinella occurs commonly in wild animals such
as foxes, wolves and bears. Smaller mammals
such as skunks, raccoons and rats, which
commonly associate with people, are the main
sources of domestic pig infections.

55. http://www.foodsafetyindia.nic.in/images/Trichinella_LifeCycle.gif

56. Trichina worms
 Pigs may become infected by eating fecal matter
or the bodies of animals infected with the
parasite. Humans are an inadvertent host of
Trichinella.
 In humans, infection with a few Trichinella
parasites may cause no symptoms, but heavy
infections can cause intense muscle pain and in
some cases death.