This document summarizes several human pathogen helminth parasites classified into three groups - Trematoda, Cestoda, and Nematoda. Key details are provided on the life cycles, transmission, clinical symptoms, diagnosis, treatment and prevention of Fasciola hepatica (sheep liver fluke), Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), Ascaris lumbricoids (human roundworm), Ancylostoma duodenale (hookworm), Wuchereria bancrofti (filarial worm), and Drancunculus medinesis (guinea worm).

1. HUMAN PATHOGEN
HELMINTH PARASITES
RATHEESH R.L

2. • Human pathogen helminth parasites are mainly
classified under three groups.
– TREMATODA
• Fasciola hepatica
• Fasciolopsis buski
• Clonorichs sinensis
– CESTODA
• Schistosoma haematobium
• Taenia solium
• Taenia saginata
• Taenia echinococcus

3. – NEMATODA
• Ascaris lumbricoids
• Trichuris trichura
• Ancylostoma duodenale
• Enterobius vermicularis
• Wuchereria bancrofti
• Drancunculus medinesis

5. Fasciola hepatica ( sheep liver fluke)
• HABITAT: It lives in the bile duct of sheep, ox,
goat and man

6. LIFE CYCLE
• The life cycle is completing in two hosts: man
and snails.
• Fasciola hepatica is a parasite living in the liver
and bile duct of man and sheep.
• The adult worm discharges immature eggs in
the bile duct and in stool.
• Eggs become embryonated in water and
releases larvae which invade a suitable snail.

7. • A human eats the raw freshwater plant
containing the cyst will get the infection.
• After ingestion it will spreads to the
duodenum, intestinal wall, peritoneal cavity
and liver.

8. CLINICAL FEATURES
• The disease caused by the fasciola hepatica is
known as fascioliasis.
• In the chronic phase of fascioliasis it cause
liver inflammation and obstruction of the
biliary fluid. other symptoms include:
– diarrhea
– eosinophilia (high number of white blood cells)
– fever
– nausea
– stomach ache
– vomiting.

9. LABORATORY DIAGNOSIS
• MICROSCOPY:
– Eggs can be identify in the stool of infected
persons under a microscope.
• ANTIBODY DETECTION TEST:

10. TREATMENT
• Triclabendazole is the drug of choice

11. PREVENTION
• Avoid eating raw fresh water plants
• Avoid drinking contaminated water
• Drink only purified and boiled water

13. Taenia solium (pork tape worm)
Taenia saginata (beef tape worm)
HABITAT:
Taenia solium: Lives in the intestine
Taenia saginata: Lives in the mucosal wall
of ileum.

14. LIFE CYCLE
• Taeniasis is the infection of humans with the
adult tapeworm of Taenia saginata or Taenia
solium.
• Eggs are passed with feces ; the eggs can
survive for days to months in the environment.
• Cattle (T. saginata) and pigs (T. solium) become
infected by ingesting vegetation contaminated
with eggs

15. • In the animal intestine the eggs rupture with
liberation of onchospheres.
• These onchospheres invade to the intestinal
wall and migrate to the striated muscles of the
animal and they develop into cysticerci.
• A cysticercus can survive for several years in
the animal. Humans become infected by
ingesting raw or undercooked infected meat

16. • In the human intestine, the cysticercus
develops over 2 months into an adult
tapeworm, which can survive for years.
• The adult tapeworms attach to the small
intestine.
• Then the adult female tapeworm starts to
produce eggs and the life cycle will be
repeated.

17. CLINICAL FEATURES
• The infection with the taenia species is known
as taeniasis.
• Most people that have taeniasis don’t have
any symptoms. If signs and symptoms are
present they may include:
– pain
– unexplained weight loss
– blockage of the intestine
– digestive problems
– Fiscomfort
– Hunger
– constipation

18. DIAGNOSIS
• MACROSCOPY:
– Examination of stool for adult worms
• MICROSCOPY:
– Demonstrates the presence of eggs in the feces
• SEROLOGICAL TESTS:
– Indirect haemagglutination
– ELISA
– Immunoflurescent assay.

19. TREATMENT
• The drug of choice are
– Niclosamide
– Albendazol
– mebendazole and
– praziquantal

20. TRANSMISSION
• By eating under cooked beef or pork
• By drinking contaminated water

21. PREVENTION
• Eat the food items only after proper cooking.

22. NEMATODA
(round worm)

23. • The family includes the parasites,
• Ascaris lumbricoids
• Trichuris trichura
• Ancylostoma duodenale
• Enterobius vermicularis
• Wuchereria bancrofti
• Drancunculus medinesis

24. Ascaris lumbricoids ( human round worm)
HABITAT:
lumen of the small intestine

25. LIFE CYCLE
• Life cycle is completed only in man.
• Adult worms live in the lumen of the small
intestine.
• A female may produce up to 240,000 eggs per
day, which are passed with the feces
• Fertile eggs embryonate and become infective
after 18 days to several weeks , depending on the
environmental conditions (optimum: moist,
warm, shaded soil).

26. • After infective eggs are swallowed , the larvae
invade the intestinal mucosa, and are carried
via the portal and systemic circulation to the
lungs.
• The larvae mature further in the lungs (10-14
days), penetrate the alveolar walls, ascend the
bronchial tree to the throat, and are
swallowed.

27. • Upon reaching the small intestine, they
develop into adult worms and the life cycle is
repeated.

28. CLINICAL PICTURE
• The infection caused by the Ascaris
lumbricoids is known as intestinal ascariasis.
• Infections with a large number of worms may
cause abdominal pain or intestinal
obstruction.
• Other symptoms are, abdominal pain,
intestinal obstruction, poor digestion,
diarrhea, appendicitis, cough, dyspnoea and
hemoptysis.

29. DIAGNOSIS
• MICROSCOPY:
– During pulmonary migration larvae can be
identified in sputum and gastric aspirate.
• MACROSCOPY
– Detection of adult worms in stool
– Scratch test

30. TREATMENT
• Albendazole
• Mebendazole
• Piperazine
• Decaris and
• pyrantel pamoate

31. TRANSMISSION
• Contaminated water, foods especially raw
vegetables which may contain eggs of the
parasite.
• Unhygienic sanitation

32. PREVENTION
• Drink clean and boiled water
• Wash hands thoroughly
• Use properly cooked vegetables.

33. ANCYLOSTOMA DUODENALE( HOOK
WORM)
HABITAT:
Small intestine particularly in the jejunum.

34. LIFE CYCLE
• Man is the only host. Adult worms live inside the
jejunum part of the small intestine of man.
• Females lay egg after fertilization which are
passed out with stool.
• Under favorable conditions the eggs will remain
in the soil.
• Then the larvaes are produced in the soil/feces
from the eggs known as rhabditiform larvae.

35. • These rhabditiform larvae will transform to
the form of filariform larvae that are infective
and it will remain in the grass and soil.
• When a person walking bare footed or coming
contact with the filariform larvae, it will
penetrate directly through the skin or hair
follicles to the subcutaneous tissue.
• From the subcutaneous tissue, it will finally
reaches the lymphatic system and small
venules.

36. • Through the blood stream it will reaches to
the heart and lungs.
• In lungs they penetrate pulmonary alveoli,
bronchioles, trachea, larynx and swallowed
back to stomach.
• Again the larvae reach to small intestine and
the cycle is repeated.

37. CLINICAL PICTURE
• The infection by the ancylostoma duodenale is known
as ancylostomiasis or hookworm disease.
• if the patient experience symptoms, they generally
start with itchiness and a small rash caused by an
allergic reaction as the larvae enters to the skin.
• Commonly the symptoms of anemia will also occur.

38. • Other symptoms include:
– abdominal pain
– intestinal cramps
– nausea
– fever
– blood in your stool
– appetite loss
– itchy rash

39. DIAGNOSIS
• MICROSCOPY:
done to demonstrate eggs in stool.
• BLOOD STUDIES
To reveal anemia
• STOOL EXAMINATION
To find out the presence of occult blood in
stool

40. TREATMENT
• Albendazole
• Mebandazole
• Pyrantel pamoate.

41. TRANSMISSION
• Transmission occurs by walking bare footed or
coming in direct contacted with the
contaminated soil.
• Rarely transmission can be occur through oral
route by the accidental drinking of
contaminated water.

42. PREVENTION
• Avoid walking bare foot
• Hygienic sanitary conditions

43. Wuchereria bancrofti
HABITAT:
Adult worms lives in the lymphatic
vessels and lymph nodes of man while as
microfilaria are found in the blood.

44. LIFE CYCLE
• It is a digenetic parasite as it completes its life
cycle in two hosts.
• The primary or definitive host is man, while the
secondary or intermediate host is several species
of mosquitoes belonging to genus Сulex, Aedes
and Anopheles.
• The adult worm lives inside the lymphatic vessels
and lymph nodes of human beings.

45. • After fertilization the female produces larvae.
During day time it remains in deeper blood
vessels and at night in the capillaries of the
skin.
• These larvae does not develop until it is
sucked by the mosquitos.
• During bite the mosquito the larvae reaches to
the mosquito gut.

46. • Then the larvae penetrate the gut and reaches
to the thoracic muscles.
• In the thoracic muscles it changes to the
infective form. ( filariform larvae)
• After 2 moultings these larvae moves to the
mouth of the mosquito and when such
mosquito bites an individual these larvae
enters to the human body especially on the
lymphatics of the patient.

47. • From the lymphatic system it reaches to
various parts of the body and the cycle is
repeated.

48. CLINICAL PICTURE
• The disease caused by the Wuchereria bancrofti
is known as lymphatic filariasis.
• Other symptoms are,
– Fever
– Headache
– Myalgia
– Lymphadenitis
– Lymphadenopathy
– Inflammation of lymphatics
– Lymphatic dysfunction
– Progressive swelling of limbs
– Progressive swelling of genitalia
– Elephantiasis

49. DIAGNOSIS
• MICROSCOPY:
• Doing to demonstrate the larvae form.
• DEMONSTRATION OF ADULT WORM
• By lymph node biopsy
• SEROLOGICAL STUDIES
• ELISA, RIA, CFT, IFA & PCR

50. TREATMENT
• Diethyl carbamazine is the drug of choice.

51. PREVENTION
• Using mesh doors and nets.
• Use mosquito repellents
• Eliminate the breeding grounds of mosquito
• Chemical sprays.

52. Drancunculus medinesis (guinea worm)
HABITAT:
the adult female guinea worm lives in the
sub cutaneous tissue of legs , arms and back.

53. LIFE CYCLE
• Humans become infected by drinking unfiltered
water containing with the of Drancunculus
medinesis.
• Following ingestion, the eggs will die and release
the larvae, which penetrate the host stomach and
intestinal wall and enter the abdominal cavity and
retroperitoneal space.

54. • After maturation into adults, the male worms die
and the females migrate in the subcutaneous
tissues towards the skin surface.
• Approximately one year after infection, the
female worm induces a blister on the skin,
generally on the distal lower extremity, which
ruptures.

55. • When this lesion comes into contact with
water the patients develop local discomfort
and the larvae will spreads to the water.
• Thus is the cycle is repeated.

56. CLINICAL PICTURE
• The infection in man is called as dracunculosis
and is commonly known as guinea worm disease.
• The other symptoms are,
• Fever
• Local swelling
• Local pain
• Chronic skin ulcers
• Visible worms in skin ulcers
• Painful skin bumps
• Nausea
• Vomiting
• Diarrhea

57. DIAGNOSIS
• Detection of adult worm
• Detection of embryo
• Intra dermal test

58. TREATMENT
• Local cleansing of lesion and local application
of antibiotics.
• Mechanical extraction of worms.
• Ambithus is the drug of choice

59. PREVENTION
• DRINK CLEAN AND BOILED WATER.
• USE CLEAN WATER FOR BATHING ALSO.