Naegleria fowleri & Acanthamoeba Ashley Skellie & Karissa Jensen

Naegleria fowleri

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. http://www.cdc.gov/parasites/naegleria/

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

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

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

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

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 http://www.google.com/imgres?q=naegleria+fowleri&um=1&hl=en&sa=N&biw=982&bih=519&tbm=isch&tbnid=hcoFt2KP4VoCqM:&imgrefurl=http://en.wikipedia.org/wiki/Naegleria_fowleri&docid=Pshf2fEWF1WGUM&imgurl=http://upload.wikimedia.org/wikipedia/commons/3/33/Naegleria_%28formes%29.png&w=153&h=117&ei=kQUeT77tB6_gsQLs_v3BDg&zoom=1&iact=hc&vpx=337&vpy=244&dur=141&hovh=93&hovw=122&tx=41&ty=24&sig=100583659001546492190&page=1&tbnh=93&tbnw=122&start=0&ndsp=10&ved=1t:429,r:1,s:0

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 http://www.google.com/imgres?q=meningoencephalitis&start=20&num=10&um=1&hl=en&biw=856&bih=513&tbm=isch&tbnid=DYT4fgqWSSO3TM:&imgrefurl=http://www.medscape.com/viewarticle/423486&docid=SpmcF5XCnc3fgM&imgurl=http://img.medscape.com/fullsize/migrated/423/486/iim423486.fig1.jpg&w=380&h=517&ei=OvocT8u4FIHdgQfHiIjyCw&zoom=1&iact=hc&vpx=357&vpy=126&dur=81&hovh=262&hovw=192&tx=119&ty=290&sig=100583659001546492190&sqi=2&page=3&tbnh=161&tbnw=125&ndsp=12&ved=1t:429,r:6,s:20

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

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.

Acanthamoeba

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

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

Hosts Definitive Intermediate Inhabitants of: Humans None All types of water Heating, ventilating, and air conditioning systems Dust Soil http://www.google.com/imgres?q=airconditioner&um=1&hl=en&biw=482&bih=532&tbm=isch&tbnid=v1YedzQGoUM1ZM:&imgrefurl=http://www.whirlpoolhvac.com/products/air_conditioners&docid=u8D6_i73McdfDM&imgurl=http://www.whirlpoolhvac.com/images/WP-WAC4318-isometric_display.jpg&w=275&h=275&ei=01QgT93wK4i3sQK3xsjQDg&zoom=1 http://www.google.com/imgres?q=people&num=10&um=1&hl=en&biw=482&bih=532&tbm=isch&tbnid=7RQvVIF8SDcKCM:&imgrefurl=http://ed101.bu.edu/StudentDoc/current/ED101fa10/emfoley2/content1.html&docid=vBJOz8E7TvN8FM&imgurl=http://ed101.bu.edu/StudentDoc/current/ED101fa10/emfoley2/Images/communitypeople.jpg&w=1203&h=1024&ei=ZVUgT6yMI6aksQLgyoSTDg&zoom=1&iact=hc&vpx=203&vpy=215&dur=1207&hovh=207&hovw=243&tx=148&ty=152&sig=100583659001546492190&sqi=2&page=1&tbnh=123&tbnw=144&start=0&ndsp=7&ved=1t:429,r:4,s:0 http://www.google.com/imgres?q=water&num=10&um=1&hl=en&biw=482&bih=532&tbm=isch&tbnid=L73Dwc8okR-zSM:&imgrefurl=http://www.osawaterworks.com/&docid=GkvUDSX8I9TJbM&imgurl=http://www.osawaterworks.com/images/water%252520art-4.jpg&w=800&h=640&ei=IlUgT5XxB_LLsQKr_rGWDg&zoom=1&iact=rc&dur=406&sig=100583659001546492190&sqi=2&page=1&tbnh=142&tbnw=193&start=0&ndsp=6&ved=1t:429,r:0,s:0&tx=138&ty=56

Morphology Cyst Trophozoite Double-walled Dormant Highly resistant Infectious stage Reproduction http://www.google.com/imgres?q=acanthamoeba&um=1&hl=en&sa=N&biw=929&bih=526&tbm=isch&tbnid=1mthR3wEARbLPM:&imgrefurl=http://dpd.cdc.gov/dpdx/HTML/Frames/A-F/FreeLivingAmebic/body_FreeLivingAmebic_mic1.htm&docid=JZ-CbYpquHuU4M&imgurl=http://dpd.cdc.gov/dpdx/images/ParasiteImages/A-F/FreeLivingAmebic/Acanthamoeba_HE_Vish3.jpg&w=300&h=300&ei=lT4gT7a4IKz_sQLA_5S7Dg&zoom=1&iact=hc&vpx=668&vpy=172&dur=1275&hovh=225&hovw=225&tx=79&ty=107&sig=100583659001546492190&page=1&tbnh=139&tbnw=139&start=0&ndsp=8&ved=1t:429,r:3,s:0

Means of Infection Ruptured skin Inhaled through the nose Eye   http://www.youtube.com/watch?v=C6ZEHUg2bgk

Life Cycle

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

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

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.

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

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?

References http://www.stanford.edu/group/parasites/ParaSites2010/Katherine_Fero/Fero Naegleriafowleri.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-eating-amoeba- death_n_1155334.html http://www.youtube.com/watch?v=C6ZEHUg2bgk http://webeye.ophth.uiowa.edu/eyeforum/cases/58-Acanthamoeba-Keratitis- Contact-Lens-Wear-Pain-Ring-Infiltrate.htm