The document discusses several intestinal protozoa and helminths including Ascaris lumbricoides, hookworms, Entamoeba histolytica, Giardia lamblia, and Cryptosporidium. It describes the morphology, life cycles, transmission routes, clinical manifestations, diagnosis, and treatment of each parasite. Prevention focuses on proper sanitation, hygiene practices like handwashing, water treatment, and health education.

1. INTESTINAL HELMINTHS &
INTESTINAL PROTOZOA
Submitted By :-
Dr.Laximan Sawant
(L-2011-V-91-M)

2. IntestInal helmInths

3. Ascaris

4. • Ascaris is a genus of parasitic nematode worms known as the
"giant intestinal roundworms".
• One species, A. suum, typically infects pigs,
• while another, A. lumbricoides, affects human populations,
typically in sub-tropical and tropical areas with poor
sanitation.

5. • A. lumbricoides is the largest intestinal roundworm
and is the most common helminth infection of
humans worldwide, an infection known as ascariasis.

6. Morphology
Fertile egg
• mammillated
• thick external layer

7. Morphology Cont.
Infertile egg
• elongated and larger than
fertile egg
• thin shelled

8. Morphology Cont.
 Infertile  Fertile

9. Adult worm:
 tapered ends; length
15 to 35 cm
 Female are larger in
size and have a
genital girdle

10. Adult worm of A. lumbricoides

11. The 3 prominent “lips”

12. TRANSMISSION
 Ascariasis is not spread directly from one person to
another.
 By the FAECAL-ORAL route, i.e., by ingestion of
infective eggs with food or drink.
 Foods that are eaten raw such as salads and
vegetables readily convey the infection, and so is
polluted water.

13. • There is increasing evidence that dust may
play an important role in the dissemination of
ascaris in arid areas.

14. Pre-patency:
2 months
Pneumonitis:
4 – 16 days after
infection,
short duration
(~3 wks)

15. Symptoms
1. Symptoms associated with larvae migration
• eosinophilic pneumonia, cough (Loeffler's Syndrome)
• Breathing difficulties and fever
• Complications - asthmatic attacks, pulmonary infiltration

16. Löeffler Syndrome (Pneumonitis)
Transverse sections of
Ascaris larvae in
pulmonary alveoli

17. Symptoms Cont.
2. Symptoms associated with adult parasite in the intestine
• Usually asymptomatic
• Abdominal discomfort, nausea in mild cases
• Malnutrition
• Sometimes fatality may occur when mass of worm blocks the
intestine

18. Adult Ascaris
worms migrating in
liver

19. Ascaris causing
intestinal
obstruction.

21. Ascaris
(roundworm):
The only
nematode ever
coughed or
vomited up

22. Diagnosis
• Stool microscopy :
• Eosinophilia: eosinophilia can be found, particularly during
larval migration through the lungs
• Ultrasound: ultrasound exams can help to diagnose
hepatobiliary or pancreatic ascariasis.
• Endoscopic Retrograde Cholangiopancreatography (ERCP) :
A duodenoscope with a snare to extract the worm out of the
patient

23. Treatment
• Mebendazole
• Albendazole

24. Prevention
• Proper washing of the vegetables.
• Health education.
• Washing hands before meals.
• Mass treatment for the patients.
• Sanitary disposal for the feces.
• Avoid uses of feces as manures.

25. The Human Hookworms
Necator americanus
Ancylostoma duodenale

26. Morphology
1. Adults: They look like an odd piece
thread and are about 1cm.
2. They are white or light pinkish when
living. ♀is slightly larger than♂.

27. 2. Eggs: oval in shape, shell is thin and colorless.
Content is 2-8cells.

28. Acylostoma duodenale & Necator
americanus -- human hookworms
• Small nematodes (1-1.5 cm)
• Head is slightly bend (hook)
and the ‘mouth’ carries
characteristic teeth
(Ancylostoma) or plates
(Necator,

29. • note the presence of four "teeth," two on each
side.

30. Necator americanus
• Note the presence of two cutting "teeth“.

31. Pathogenesis and Clinical
Manifestations
• Skin penetration and
associated secondary
bacterial infection can
result in “ground itch”
• Pulmonary phase is
usually asymptomatic
• Intestinal phase: worms
attach to the mucosa and
feed on blood. Worms
continuously move to
new places exacerbating
bleeding

32. Hookworms
• The main concern with hook
worm disease is blood loss
• 0.03 ml to 0.26 ml (A.d) per
worm, up to 200 ml per day in
heavy infections
• Chronic heavy infection results
in anemia and iron deficiency

33. Adults in intestinal mucosa

34. Diagnosis
Criterion:
1. Hemoglobin is lower than 120g/L in man, 110g/L in
woman.
2. find hookworm egg
Method:
1. saturated brine flotation technique
2. direct fecal smear
3. culture of larvae

35. TREATMENT
1. Albendazole
2. Mebedazole

36. Prevention
1. sanitary disposal of night soil
2. individual protection
3. health education
4. cultivate hygienic habits
5. treat the patients and carriers.

38.  Entamoeba histolytica
(amoebiasis)

39. Transmission
• Amoebiasis is usually transmitted by the
fecal-oral route,
• but it can also be transmitted indirectly through
contact with dirty hands or objects as well as by
anal-oral contact.

41. Pathology and
Clinical Manifestation
• Pinpoint lesion on mucous membrane
• Flask-shaped ulcers

42. A. Intestinal amoebiasis
• a. dysentery: dysenteric stools (pus and blood
dysentery:
without feces). fever, dehydration, and
electrolyte abnormalities.
• b. non-dysenteric colitis
• c. appendicitis
• d. amoeboma: may become the leading point
of an intussusception or may cause intestinal
obstruction.

44. Histopathology of a typical flask-shaped
ulcer of intestinal amebiasis

45. B. Extra-intestinal amoebiasis
• a. Hepatic
• (1) acute non-suppurative
• (2) liver abscess:
• b. Pulmonary

46. Amoebic Liver Abscess

47. Gross pathology of liver containing amebic
abscess

48. Gross pathology of amebic abscess of liver. Tube of
"chocolate" pus from abscess.

49.  Note the reddish
brown colour of
the pus . This
colour is due to the
breakdown of liver
cells.

50. Diagnosis
1. Stool examination
2. Serologic studies: indirect hemagglutination, skin
tests, ELISA and latex agglutination.
3. Tissue examination: biopsy, aspiration

51. Treatment and Prevention
• Treatment:
• Diodoquin-carriers
• Metronidazole-dysentery, liver abscess

52. Preventing Amoebiasis
• Drink only bottled or boiled (for 1 minute) water.
• Fountain drinks and any drinks with ice cubes are not safe.
Water can be made safe by filtering it through an "absolute 1
micron or less" filter and dissolving iodine tablets in the
filtered water.
• Avoid milk, cheese, or dairy products that may not have been
pasteurized.

53. Food safety
• Thoroughly cook all raw foods.
• * Thoroughly wash raw
vegetables and fruits before
eating.
• * Reheat food until the internal
temperature of the food
reaches at least 167º
Fahrenheit.
• Wash your hands before
preparing food, before eating,
after going to the toilet or
changing diapers,

54. Trophozoites Cysts

55. Epidemiology
Distribution
Worldwide distribution, endemic and epidemic.
Traveler diarrhea
Patients with variable immunodeficiency are
increasingly susceptible to infection with Giardia.

56. Epidemiology
Transmission source
Persons whose feces containing cysts
Monkeys and pigs can also be infected, the infected
pig may be a source of human infection.
Transmission
drinking contaminated water
Infected by
eating contaminated food

58. Diagnosis
Pathogenic examination
(1) Fecal examination
(2) Duodenal fluid or bile examination
(3) Intestinal examination by gelatin capsule

59. Diagnosis
Immunological diagnosis
ELISA: enzyme-linked immunosoebent assay
IFA: indirect fluorescent antibody

60. Cysts have strong resistance
Cysts can keep alive 10 or more days in feces
Cysts are often waterborne, either by taking
inadequately treated municipal water supplies
of contaminated river or stream
Giardiasis is more common in travelers,
Immunodeficiency persons

61. Prevention and control
Treat the patients and cyst carriers
Metronidazole
Tinidazole
Treatment of the drinking water
Suspect water should be boiled or adequately
filtered to remove the infective cysts before
drinking.

62. CRYPTOSPORIDIUM

63.  fecal-oral
 Animal to human
 Contamination of
water supplies (result
of waste runoff)
 *WATER-BORNE
MOST COMMON*
COMMON

64. SYMPTOMS
• Immunocompetent • Immunocompromised
– Mild self-limiting – 50 or more stools per
enterocolitis (watery day
bloodless diarrhea, – Dehydration (fatigue,
abdominal pain, nausea, abdominal cramping,
vomiting, and fever) and nausea)
– Common in AIDS
patients

65. LAB DIAGNOSIS
 Microscopic exam
 Acid
fast stain of stool
sample
 Endoscopic biopsy of
small intestine

66. Cryptosporidium oocysts with acid-fast stain

67. LAB DIAGNOSIS
 Immunodiagnosis
 Immunofluorescence
assay (IFA)
 Enzyme linked
immunoabsorbant
assay (ELISA)
 Polymerase Chain
Reaction (PCR)
 Test of choice

68. • Infectious agents are the OOCYSTS
• In immunocompromised patients ID50 is about 10
to 30 oocysts

70. TREATMENT
• Immunocompetent • Immunocompromised
– Self-limiting – Cocktail therapy -used
to treat symptoms but
– Usually symptoms
NOT THE DISEASE
subside within 10
– Drugs include: letrazuril,
days azithromycin, paramycin,
and hyperimmune bovine
colostral
immunoglobulin
*The only immunity is previous exposure and
extent of this immunity is not known.*

71. PREVENTION
• Wash hands
• Wash fruits and
vegetables
• Avoid untreated water
• Treat contaminated
water
• MAINTAIN PROPER
HYGIENE!!

72. WATER PREVENTION
• Ozone
• UV light
• boiling
• “Chlorine not
effective against
crypto!!”

74. CONTROL OF PROTOZOA IN
DRINKING WATER
 Multiple barrier approach:
 Filtration
 Chemical inactivation- ozone, combination of
disinfectants
 Medium-pressure ultraviolet light (UV)
 Monitoring:
 Presence of protozoa in raw water