Amoeba infecting brain and eyes

2. 
 Among the many genera of free-living amoebae that
exist in nature, members of only four genera have an
association with human disease: Acanthamoeba spp.
Balamuthia mandrillaris, Naegleria fowleri and
Sappinia pedata.
 They are aerobic unlike other amoebae which are
anaerobic
Introduction

3. 
 They have also been called amphizoic amoebae
because these amoebae have the ability to exist as
free-living organisms in nature.
 Only occasionally invade a host and live as parasites
within host tissue.
Introduction

4. 
 Among thses four genera:
Naegleria fowleri is called as brain eating
amoeba
 Acanthamoeba Keratitis is called eye eating
parasites
Introduction

5. 
 Naegleria fowleri, commonly found in warm
freshwater (like lakes, rivers, and hot springs) and
soil, is the only species of Naegleria known to infect
people.
 Naegleria fowleri is an amoeboflagellate, as it has a
transitory, pear-shaped flagellate stage along with
amoeboid trophozoite and resistant cyst stages in its
life cycle
Naegleria fowleri

6. 

7.  Naegleria loves very warm water. It can survive in water as
hot as 113 degrees Fahrenheit.
1. Warm lakes, ponds, and rock pits
2. Mud puddles
3. Warm, slow-flowing rivers, especially those with low water
levels
4. Untreated swimming pools and spas
5. Untreated well water or untreated municipal water
6. Hot springs and other geothermal water sources
7. Thermally polluted water, such as runoff from power plants
8. Aquariums
9. Soil, including indoor dust
Occurance

8. 
 N.fowleri exists in three forms;
1. Trophozoite or amoeboid form
2. Flagellate form
3. Cyst or resting form
Forms of N. fowleri

9. 
 Found on surface of vegetation and mud.
 The trophozoite moves rapidly by producing
rounded pseudopodia(lobopodia)
 Size → 6-15µm in diameter.
 Slug shaped
 Observed in the CSF and in tissue of brain .
Trophozoite form

10. 
 Pear shaped cell with 2 flagella
 Found in surface layer of the water
 Rapidly motile
 Not found in CSF or brain
Flagellate form

11. 
 They are uninucleated and possess double cyst wall.
 Found on the surface of vegetation and mud.
 Not found in CSF or in brain.
Cyst or resting form

12. 

13. 
 Trophozoites infect humans or animals by
penetrating the nasal mucosa and migrating to the
brain via the olfactory nerves causing primary
amoebic meningoencephalitis (PAM).
 N. fowleri trophozoites are found in cerebrospinal
fluid (CSF) and tissue, while flagellated forms are
occasionally found in CSF.
Infection

14. 

15. 

16. 
 Naegleria fowleri causes an acute, fulminating
hemorrhagic meningoencephalitis principally in
healthy children and young adults with a history of
recent exposure to warm fresh water.
 The striking feature of PAM is the rapid onset of
symptoms following exposure.
 The disease progresses rapidly, and, without prompt
diagnosis and intervention, death usually occurs
within a week or less
Primary Amoebic
Meningoencephalitis

17. 
 The time from initial contact(swimming, diving,
water skiing, or simply immersing head in water) to
onset of illness is usually 5–7 days, and may even be
as short at 24 hours.
Initial contact

18. 

19. 
 The earliest symptoms are sudden onset of bifrontal
or bitemporal headaches, high fever,nuchal rigidity,
followed by nausea, vomiting, irritability and
restlessness.
 Photophobia may occur late in the clinical course,
followed by neurological abnormalities, including
lethargy, seizures, confusion, coma, diplopia or
bizarre behavior, leading to death within a week.
Symptoms

20. 
 Few patients have survived PAM.
 Large dose of antifungal agent amphotericin-B (1
mg/Kg/day I.V. for several days) or ketoconazole
(800 mg daily orally for one month).
Azithromycin, a macrolide antimicrobial, has been
shown to be effective against Naegleria both in vitro
and in vivo
Survival

21. 
 Chlorination of heavily used swimming pools,
especially during summer months.
 In high-risk areas, monitoring of recreational waters
for N. fowleri amoebae should be considered by local
public health authorities
 APPROPRIATE warnings posted, particularly
during the hot summer months.
Preventions

22. 

23. 
 Sir Aldo Castellani
 Delicate structures of clear cytoplasm that protruded
fromthe cell-acanthopodia
 22 species of Acanthamoeba have been
distinguished bycyst morphology,
immunofluorescence antibody tests, orisoenzyme
studies
ACANTHOMOEBA KERATITIS

24. 
Found in all types of water bodies.
Highly resistant to temperature
extremes.
Occurance

25.  2 forms:
 i) Dormant cyst ii)Active Trophozoite( infectious)
 Adverse conditions- encyst in double wall of cellulose
 Cysts are hardy and survive up to 1 yr- size 15-45 um.
 Convert to trophozoite in favourable conditions-
motile andfeed on bacteria, fungi, and unicellular
organisms.
Forms

26. 

27. 

28. 
 Relatively uncommon
 First case reported in 1974
 Direct corneal contact withorganism
 Contact with liquid contaminated with organism
 Contact lens use
 Contaminated contact lens solutions- made from
distilledwater/ tap water with salttablets
ACANTHAMOEBA
KERATITIS

29. 
 Severe eye pain
 Redness irritation
 FB sensation
 Photophobia
 reactive ptosis
 enlarged pre-auricular lymph node
Symptoms

30.  Pain 50-100 %
 Reduced corneal sensation 29%
 Epithelial defects
 erosions 60%
 Stromal ring infiltrate 6-29%
 Other stromal infiltrate 33%
 Radial keratoneuritis 2-57%
 Limbitis 84-94%
 Hypopyon 39%
 Cataract 20%
Signs

31. 
Epithelitis

32. 
Late disease

33. 

34. 