Naegleria fowleri& Acanthamoeba

Ashley Skellie & Karissa Jensen

Naegleria fowleri

BackgroundSingle-celled amoeba30+ Naegleria speciesDiscovered in AustraliaInfections are rare

TaxonomyKingdom ProtistaSubkingdom ProtozoaPhylum SarcomastigophoraSubphylum SacodinaSuperclass RhizopodiaClass AcarpomyxeaOrder SchizopyrenidaFamily VahlkampfiidaeGenus NaegleriaSpecies fowleri

Geographic Distribution

Worldwide United States Australia Czech Republic Great Britain Mexico Czechoslovakia

Prevalent in the summer months

HostsDefinitive

HumansIntermediate

NoneInhabitants of:

SoilWarm, freshwaterGeothermal springsRecreational poolsHeated tap water

Means of InfectionInhaled through the noseCannot spread from human to humanMigrate to the brain via olfactory nervesNeti Pots http://abcnews.go.com/Health/Wellness/fatal-infections-linked-neti-pots/story?id=15170230

http://www.huffingtonpost.com/2011/12/17/brain-eating-amoeba-death_n_1155334.html

MorphologyCyst

8-12 um diameter Single-walled Spherical

Trophozoite 10-15 um diameter Infectious form Reproductive form

Flagellated formReproduce asexually

Binary fission

Life Cycle

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

Diagnosis & TreatmentEarly diagnosis is key

Cerebral spinal fluidTissue biopsyAutopsy

Amphotericin BHigh toxicity

MiconazoleHigh mortality rate

Control VectorsAvoid swimming, diving, or jumping into water

when temperatures are high and water levels are low

Hold head above waterHold nose shut; nose plugsAvoid digging up/disrupting sediment while

swimming.

Acanthamoeba

BackgroundPart of same superclass as Naegleria fowleri

Microscopic amoebaRare infection found worldwideMany species infect humansAccidently discovered in 1930

TaxonomyKingdom ProtistaSubkingdom ProtozoaPhylum SarcomastigophoraSubphylum SacodinaSuperclass RhizopodiaClass LoboseaSubclass GymnamoebiaSuborder AcanthopodinaFamily AcanthamoebidaeGenus Acanthamoeba

HostsDefinitive

HumansIntermediate

NoneInhabitants of:

All types of waterHeating, ventilating, and air conditioning systemsDustSoil

MorphologyCyst

Double-walledDormantHighly resistant

Trophozoite Infectious stageReproduction

Means of InfectionRuptured skinInhaled through the noseEye   http://www.youtube.com/watch?v=C6ZEHUg2bgk

Life Cycle

PathogenesisGranulomatous Amoebic Encephalitis

Attacks brain & spinal cordHeadachesStiff neckNauseaVomitingTirednessConfusionLack of attentionLoss of balanceSeizuresHallucinations

Immunocompromised

PathogenesisAcanthamoeba keratitis

Affects visionPainRedness Blurred visionSensitivity to lightSensation of something in the eyeExcessive tearing

Disseminated infection Infection throughout bodyRuptured skin

Diagnosis & TreatmentEarly diagnosis is essentialGranulomatous 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.

Control VectorsUse proper contact lens hygiene

Visit eye care providerWash handsAvoid water

Unclear prevention for Granulomatous Amoebic Encephalitis & disseminated infection.

Review QuestionsWhat 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?

References http://www.stanford.edu/group/parasites/ParaSites20

10/Katherine_Fero/FeroNaegleriafowleri.htm http://www.ncbi.nlm.nih.gov/books/NBK7960/ http://www.aoa.org/x8186.xml http://www.cdc.gov/parasites/acanthamoeba/ http://www.jstor.org/stable/4455900?seq=2 http://www.huffingtonpost.com/2011/12/17/brain-eati

ng-amoeba-death_n_1155334.html http://www.youtube.com/watch?v=C6ZEHUg2bgk http://webeye.ophth.uiowa.edu/eyeforum/cases/58-A

canthamoeba-Keratitis-Contact-Lens-Wear-Pain-Ring-Infiltrate.htm