INTESTINAL HELMINTHS & INTESTINAL PROTOZOA

INTESTINAL HELMINTHS & INTESTINAL PROTOZOA

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

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. •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.
Prevention

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

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
•  aa. dysentery:. dysentery: dysenteric stools (pus and blood 
without feces). fever, dehydration, and
      electrolyte abnormalities. 
•  b. non-dysenteric colitisb. non-dysenteric colitis
•  c. appendicitisc. appendicitis
•  d. 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. EpidemiologyEpidemiology
DistributionDistribution
Worldwide distribution, endemic and epidemic.
Traveler diarrhea
Patients with variable immunodeficiency are
increasingly susceptible to infection with Giardia.

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

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

59. DiagnosisDiagnosis
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 controlPrevention and control
Treat the patients and cyst carriersTreat the patients and cyst carriers
Metronidazole
Tinidazole
Treatment of the drinking waterTreatment of the drinking water
Suspect water should be boiled or adequately
filtered to remove the infective cysts before
drinking.

62. CRYPTOSPORIDIUMCRYPTOSPORIDIUM

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

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

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

66. Cryptosporidium oocysts with acid-fast stain

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

68. •Infectious agents are the OOCYSTSOOCYSTS
•In immunocompromised patients ID
50
is about 10
to 30 oocysts
      

70. TREATMENT
•Immunocompetent
–Self-limiting
–Usually symptoms
subside within 10
days
•Immunocompromised
–Cocktail therapy -used
to treat symptoms but
NOT THE DISEASE
–Drugs include: letrazuril,
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 Chlorine not 
effective against effective against 
crypto!!”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