1. Naegleria fowleri & Acanthamoeba
Ashley Skellie & Karissa Jensen

2. Naegleria fowleri

3. Background Single-celled amoeba 30+ Naegleria species
Discovered in Australia
Infections are rare
Image: L & R: Trophozoites of N. fowleri in brain tissue, stained with H&E (L) and trichrome (R). Center: Ameboflagellate trophozoite of N. fowleri. Credit: DPDx and GS Visvesvara.

4. Taxonomy Kingdom Protista Subkingdom Protozoa Phylum Sarcomastigophora
Subphylum
Sacodina
Superclass
Rhizopodia
Class
Acarpomyxea
Order
Schizopyrenida
Family
Vahlkampfiidae
Genus
Naegleria
Species
fowleri

5. Geographic Distribution
Worldwide
United States
Australia
Czech Republic
Great Britain
Mexico
Czechoslovakia
Prevalent in the summer months

6. Hosts Definitive Intermediate Inhabitants of: Humans None Soil
Warm, freshwater
Geothermal springs
Recreational pools
Heated tap water

7. Means of Infection Inhaled through the nose
Cannot spread from human to human
Migrate to the brain via olfactory nerves
Neti Pots

8. Morphology Cyst Trophozoite Flagellated form Reproduce asexually
8-12 um diameter
Single-walled
Spherical
Trophozoite
10-15 um diameter
Infectious form
Reproductive form
Flagellated form
Reproduce asexually
Binary fission

9. Life Cycle

10. Pathogenesis Primary Amoebic Meningoencephalitis
Leads to destruction of brain tissue
Early Symptoms
Headache
Fever
Nausea
Vomiting
Stiff neck
Later Symptoms
Confusion
Lack of attention
Loss of balance
Seizures
Hallucinations
Death within 1 to 12 days

11. Diagnosis & Treatment Early diagnosis is key Amphotericin B Miconazole
Cerebral spinal fluid
Tissue biopsy
Autopsy
Amphotericin B
High toxicity
Miconazole
High mortality rate

12. Control Vectors
Avoid swimming, diving, or jumping into water when temperatures are high and water levels are low
Hold head above water
Hold nose shut; nose plugs
Avoid digging up/disrupting sediment while swimming.

13. Acanthamoeba

14. Background Part of same superclass as Naegleria fowleri
Microscopic amoeba
Rare infection found worldwide
Many species infect humans
Accidently discovered in 1930

15. Taxonomy Kingdom Protista Subkingdom Protozoa Phylum Sarcomastigophora
Subphylum
Sacodina
Superclass
Rhizopodia
Class
Lobosea
Subclass
Gymnamoebia
Suborder
Acanthopodina
Family
Acanthamoebidae
Genus
Acanthamoeba

16. Hosts Definitive Intermediate Inhabitants of: Humans None
All types of water
Heating, ventilating, and air conditioning systems
Dust
Soil

17. Morphology Cyst Trophozoite Double-walled Dormant Highly resistant
Infectious stage
Reproduction

18. Means of Infection Ruptured skin Inhaled through the nose Eye 

19. Life Cycle

20. Pathogenesis Granulomatous Amoebic Encephalitis
Attacks brain & spinal cord
Headaches
Stiff neck
Nausea
Vomiting
Tiredness
Confusion
Lack of attention
Loss of balance
Seizures
Hallucinations
Immunocompromised

21. Pathogenesis Acanthamoeba keratitis Disseminated infection
Affects vision
Pain
Redness
Blurred vision
Sensitivity to light
Sensation of something in the eye
Excessive tearing
Disseminated infection
Infection throughout body
Ruptured skin

22. Diagnosis & Treatment Early diagnosis is essential
Granulomatous Amoebic Encephalitis & Disseminated Infection
Difficult to diagnose
Brain scans
Biopsies
Spinal taps
Ketoconaole, miconazole, itraconazole, fluconazole
Amphotericin B
Acanthamoeba keratitis
Scraping of eye
Confocal microscopy
Topical anti-microbial agents
Combination of propamidine, miconazole, and neomycin.

23. Control Vectors Use proper contact lens hygiene
Visit eye care provider
Wash hands
Avoid water
Unclear prevention for Granulomatous Amoebic Encephalitis & disseminated infection.

24. Review Questions
What are the definitive and intermediate hosts of both parasites?
Where can these parasites be found in the environment?
Can Naegleria fowleri be spread from human to human?
Name a disease caused by Naegleria fowleri.
Name a disease caused by Acanthamoeba.
What is the difference between the parasites’ cyst stage?

25. References
Naegleriafowleri.htm
death_n_ html
Contact-Lens-Wear-Pain-Ring-Infiltrate.htm