Non Pathogenic Amoeba and Free living pathogenic Amoeba

1. College of Health Sciences
Dep. of Medical Laboratories
Parasitology Theory
3rd stage
Lecture 3
Dr.: Shameeran S. Ismael
BVM & S, M.Sc Medical Microbiology(Parasitology),
PhD Molecular Parasitology

2. Non Pathogenic Amoebae
Non Pathogenic orcommensals Amoebae:
1. Endolimax nana
2. Iodamoeba butschlii
3. Entamoeba gingivalis
4. Entamoeba coli
5. Entamoeba hartmani
6. Blastocystis hominis(pathogenic in immuno-
compromised host)

3. 1. Endolimax nana
• Endolimax nana is a small non-pathogenic amoeba
with world wide distribution. Its life cycle is similar
to that of E. histolytica but is non invasive

4. Keys
Kingdome: Protista
Phylum: Protozoa
Sub-phylum: Sarcomastigophora
Class: Sarcodina
Order: Amoebida
Family: Entamoebeidae
Genus:Endolimax
Species: nana

5. Disease: Amoebiasis
Final host: Man
Site of infection: Large intestine
Infective stage: Mature cyst
Diagnostic stage: Trophozite and Cyst
Life cycle: Direct
Infection: Occur by ingestion of the contaminated food &
water with mature cyst
Shameeran S. Ismael protozology
theory.Dep.Medical Laboratories, 2020

6. Morphology
Have two stages:
1,Trophozoite:
• Trophozoite of E. nana measures from 6-12 μm.
Motility is sluggish with blunt hyaline pseudopodia
• Have a single nucleus with a large karyosome, no
peripheral chromatin on the nuclear membrane

7. 2.Cyst :
• Cysts of E. nana are 6 - 9 μm in diameter. They can
be spherical or ovoid in shape
• Have 4 pin-point nuclei with a large karyosome
which is often irregular in outline.

9. 2. Iodamoeba butschlii
Have two stages:
1. Trophozoite stage:
• Trophozoites of I. butschlii are 8 - 20 μm and are
actively motile.
• Have single nucleus with a large prominent
karyosome, which is separated from the nuclear
membrane by a mass of chromatin granules. No
peripheral chromatin (bull’s eye like)
• The cytoplasm appears granular containing vacuoles
with ingested bacteria and debris.

10. 2. Cyst
• Cysts of I. butschlii are 9 - 15 μm in diameter
• Have one nucleus, eccentrically placed.
• Chromatoid bodies are not present.
• Glycogen is present as a compact well defined mass
staining dark brown with iodine.
Trophozoite form Cyst form

11. 3. Entamoeba gingivalis
• Just have one stage is Trophozoite stage and there is
no cyst
• Its size is ranges from 8 to 20 μm and
morphologically resembles that of E. histolytica
• Trophzoites characteristically exhibit active motility .
The multiple pseudopods vary in their appearance

12. •Have a single nucleus contains a central karyosome
surrounded by peripheral chromatine

13. 4. Entamoeba coli
Have two stages:
1.Trophozoite:
• The trophozoite is larger than that of E. histolytica
ranging from 15-50 μm in diameter. It exhibits blunt
pseudopodia with sluggish movement.
• Have a single nucleus with a moderately large
eccentric karyosome with the chromatin clumped on
the nuclear membrane.
• The cytoplasm appears granular containing vacuoles
with ingested bacteria and other food particles.

14. 2. Cyst:
• Cysts of E. coli are 15 - 30 μm in diameter
• Have 1 - 8 nuclei. Chromatoid bodies are not
frequently seen but when present they are usually
splinter-like with pointed ends.
• Glycogen is usually diffuse but in young cysts is
occasionally found as a well defined mass which
stains reddish brown with iodine.

15. 5.Entamoeba hartmani
1. Trophozoite
• Morphology of the trophozoite is similar to those of
E. histolytica/dispar but they do not contain ingested
red blood cells and the motility is less rapid.
Trophozoite form
Cyst form

16. 2. Cyst
Cysts of E. hartmanni 7-9 μm in diameter and contain 1
- 4 nuclei. Chromatoid bodies are usually present in
young cysts as elongated bars with bluntly rounded
ends.
Glycogen is usually diffuse, but in young cysts it is
often present as a concentrated mass, staining reddish
brown with iodine.

17. 6. Blastocystis hominis
• Blastocystis hominis was previously considered a
yeast. It has recently been reclassified as a protozoa
Morphology:
Have three stages: Vacuolated, amoeboid and granular
stage
1.Vacuolated form is usually seen in stool sample,
characterized by a large central vacuole which pushes
the cytoplasm and the nucleus to the periphery.

18. 2. Amoeboid form, is a polymorphous cell slightly larger
than the vacuolated form and is seen in stool sample
3. Granular form, is seen in old culture
Vacuolated form

19. Pathogenic free living Amoebae
• Free-living amoebae (FLA) , also called opportunist
amoebae are small, freely living, widely distributed in
soil and water. They are included two groups of
Amoebae:
1. Naegleria produces primary amoebic
meningoencephalitis (PAM)
2. Acanthamoebae produces granulomatous amoebic
encephalitis (GAE)

20. • The infection produced by free living amoebae is
called Tetrramoebiasis
• Another term used for these amoebae is amphizoic, it
is mean has ability to live in two worlds, as free-
living organisms (exozoic) and as endoparasites
(endozoic).

21. 1. Naegleria
• Naegleria fowleri (commonly referred to as the brain-
eating amoeba) is a free-living microscopic ameba. It
can cause infection of the brain called primary
amebic meningoencephalitis (PAM). The ameba is
commonly found in warm freshwater (e.g. lakes,
rivers, and hot springs) and soil. PAM is a waterborne
disease.

22. Keys
Kingdome: Protista
Phylum: Protozoa
Sub-phylum: Sarcomastigophora
Class: Sarcodina
Order: Schizopyrenida
Family: Vahlkampfiidae
Genus: Naegleria
Species: fowleri

23. Disease: primary amoebic meningoencephalitis
or naegleriasis
Final host: Man
Site of infection: brain
Infective stage: Cyst
Diagnostic stage: Trophozite (Both amoeboid and
flagellate forms)
Life cycle: Direct
Shameeran S. Ismael protozology
theory.Dep.Medical Laboratories, 2020

24. Infection: Acquire infection by swimming in fresh
water lakes or swimming pools containing infective
forms Trophozoite (both forms) of N.fowleri or
acquired by inhaling dust containing infective forms.
Note:
• You cannot be infected with Naegleria fowleri by
drinking contaminated water.
• The infection cannot spread from one person to
another.
• Naegleria fowleri is not found in salt water, like the
ocean

25. Morphology
• Have two stages including Trophozoite and cyst.
There are two forms of Trophozoite: amoeboid and
flagellate form
• Ameboid form: found in tissue , forms a single
pseudopod,
• dimensions 7 by 20μm, With a nucleus contain a large
central karyosome
• Flagellate form: with two flagella, pear-shaped, do
not divided
• Cyst form: uninucleate, circular 7-10μm in diameter,
nucleus is similar to troph

28. Naegleria cyst & trophozoite

29. Life cycle
• Life cycle is completed in external environment.
Amoboid form is multiplies by binary fission. Amoeboid
form is invasive stage of the parasite.
• Flagellate form of trophozoite helps in the spread of
N.fowleri to new water bodies
• The amoebae invade the nasal mucosa, pass through the
olfactory plate into the meninges and initiate an acute
purulent mengingitis. N. fowleri normally eat bacteria, but
during human infections, the trophozoites
consume astrocytes and neurons

30. Life cycle

31. Pathogenesis

32. • This acute infection is developed by the entry of N.
fowleri through nasal cavity when water is forced or
splashed into the nose. N. fowleri causes destruction
of neurons and explains why this is also known as the
“brain‐eating amoeba”; this term shows that the
enzymes and toxins of this parasite are typically
involved in the destruction (eating‐up) of the brain

33. Clinical signs
• Incubation period : 2- 15 days (Average 5 days). PAM
is characterized by similar signs and symptoms to
those of viral or bacterial meningitis including fever,
headache, stiff neck, vomiting, anorexia, seizures,
ultimately death typically occurs within 3–7 days
after the appearance of these signs and symptoms

34. • The virulence of the strain and the size of the
inoculums are involved in determining the time span
between initial contact with the pathogenic N.
fowleri and the appearance of clinical signs and
symptoms that may vary from 2 to 3 days to up to as
long as 7–15 days

35. Diagnosis
1.Detection of motile Trophozoites in saline or wet
preparation of spinal fluid, nasal discharge or tissue
biopsy
• Microscopy: -Staining with Wright or Giemsa stains
or Fluorescent stains -Appeared as small pink nuclei
with sky blue cytoplasm

36. 2. Culturing

37. Prevention
• Public education
• Adequate chlorination of public water supply
including swimming pools are the possible prevention
measures

38. Note:
• Be careful while Swimming in Warm Water,
Swimming pool etc.
• Wear Nose-Clips for Swimming.
• Use Chlorine in Swimming Pool

39. Treatment
• Treatments Involve Surgery and use of Impavido (But
it is not very effective).
• There is no such Vaccines for this Disease

40. Thanks for attention,
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