<ul><li>Naegleria fowleri </li></ul><ul><li>primary amebic meningoencephalitis (PAM) </li></ul><ul><li>Acanthamoeba spp. ...
low nutrients desiccation Naegleria Life Cycle Cyst = dormant form feeding and replicating form Trophozoite =
Naegleria fowleri <ul><li>ubiquitous genus found in fresh water lakes and ponds </li></ul><ul><li>PAM first recognized by ...
Primary Amebic Meningoencephalitis (PAM) <ul><li>1-14 days incubation period </li></ul><ul><li>symptoms usually within a f...
brain section in vitro culture “ lobopodia”
Acanthamoeba life cycle
 
Acanthamoeba <ul><li>ubiqutous ameba of the soil and water </li></ul><ul><li>Culbertson (1958) fortuitously produced dise...
Acanthamoeba Meningoencephalitis <ul><li>portal of entry unknown, possibly respiratory tract, eyes, skin </li></ul><ul><...
 
Amebic Keratitis <ul><li>predisposing factors </li></ul><ul><ul><li>ocular trauma </li></ul></ul><ul><ul><li>contact lens ...
Balamuthia mandrillaris <ul><li>first report in mandrill baboon (1990) </li></ul><ul><li>genus/species named 1993 </li></u...
Recavarren-Arce et al (Human Path. 30:269, 1999) <ul><li>10 autopsies (1985-97) of Balamuthia cases in Peru </li></ul><...
Red Tides <ul><li>‘ blooms’ of dinoflagellates </li></ul><ul><ul><li>phyto- and zooplankton </li></ul></ul><ul><ul><li>usu...
<ul><li>deplete oxygen  dead zones </li></ul><ul><li>produce toxins  fish kills </li></ul><ul><li>accumulated dinofl...
Pfiesteria piscicida <ul><li>effects observed in late 1980’s (named 1996) </li></ul><ul><ul><li>fisherman and swimmers com...
Why produce toxins ? <ul><li>accidental chemical affinity </li></ul><ul><li>self-defense (zooplankton, grazers) </li></u...
 
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Naegleria fowleri primary amebic meningoencephalitis (PAM)

Published on: Mar 3, 2016
Source: www.slideshare.net


Transcripts - Naegleria fowleri primary amebic meningoencephalitis (PAM)

  • 1. <ul><li>Naegleria fowleri </li></ul><ul><li>primary amebic meningoencephalitis (PAM) </li></ul><ul><li>Acanthamoeba spp. </li></ul><ul><li>granulomatous amebic encephalitis (GAE) </li></ul><ul><li>granulomatous skin and lung lesions (primarily immunocompromised) </li></ul><ul><li>amebic keratitis </li></ul><ul><li>Balamuthia mandrillaris </li></ul><ul><li>GAE + granulomatous skin and lung lesions (primarily healthy) </li></ul>Pathogenic Free-Living Amebae
  • 2. low nutrients desiccation Naegleria Life Cycle Cyst = dormant form feeding and replicating form Trophozoite =
  • 3. Naegleria fowleri <ul><li>ubiquitous genus found in fresh water lakes and ponds </li></ul><ul><li>PAM first recognized by Fowler (1965) </li></ul><ul><ul><li>initially thought to be Acanthamoeba </li></ul></ul><ul><li>Naegleria fowleri is only species associated with PAM </li></ul><ul><li>~ 200 documented cases worldwide </li></ul><ul><ul><li>81 in U.S. </li></ul></ul><ul><ul><li>14 cases from same lake in Virginia </li></ul></ul><ul><ul><li>16 cases from same stream feed pool in Czech Republic </li></ul></ul>
  • 4. Primary Amebic Meningoencephalitis (PAM) <ul><li>1-14 days incubation period </li></ul><ul><li>symptoms usually within a few days after swimming in warm still waters </li></ul><ul><li>infection believed to be introduced through nasal cavity and olfactory bulbs </li></ul><ul><li>symptoms include headache, lethargy, disorientation, coma </li></ul><ul><li>rapid clinical course, death in 4-5 days after onset of symptoms </li></ul><ul><li>trophozoites can be detected in spinal fluid, but diagnosis is usually at autopsy </li></ul><ul><li>4 known survivors treated with Amphotericin B </li></ul>
  • 5. brain section in vitro culture “ lobopodia”
  • 6. Acanthamoeba life cycle
  • 8. Acanthamoeba <ul><li>ubiqutous ameba of the soil and water </li></ul><ul><li>Culbertson (1958) fortuitously produced disease in mice (culture contaminant) </li></ul><ul><li>human cases first reported in the early 70's </li></ul><ul><li>73 cases worldwide of GAE as of 1991 </li></ul><ul><ul><li>39 in U.S. </li></ul></ul><ul><li>majority of patients are chronically ill, immunocompromised, or debilitated with other diseases </li></ul><ul><li>also produces amebic keratitis and skin and lung lesions </li></ul>
  • 9. Acanthamoeba Meningoencephalitis <ul><li>portal of entry unknown, possibly respiratory tract, eyes, skin </li></ul><ul><li>presumed hematogenous dissemination to the CNS </li></ul><ul><li>infection associated with debilitation or immunosuppression </li></ul><ul><li>onset is insidious with headache, personality changes, slight fever </li></ul><ul><li>progresses to coma and death in weeks to months </li></ul><ul><li>amebas not yet detected in spinal fluid </li></ul><ul><li>trophozoites and sometimes cysts detectable in histological examination </li></ul><ul><li>no human cures documented </li></ul>
  • 11. Amebic Keratitis <ul><li>predisposing factors </li></ul><ul><ul><li>ocular trauma </li></ul></ul><ul><ul><li>contact lens (contaminated cleaning solutions) </li></ul></ul><ul><li>symptoms </li></ul><ul><ul><li>ocular pain </li></ul></ul><ul><ul><li>corneal lesions (refractory to usual treatments) </li></ul></ul><ul><li>diagnosis </li></ul><ul><ul><li>demonstration of amebas in corneal scrapings </li></ul></ul><ul><li>treatment </li></ul><ul><ul><li>difficult, limited success </li></ul></ul><ul><ul><li>corneal grafts often required </li></ul></ul>
  • 12. Balamuthia mandrillaris <ul><li>first report in mandrill baboon (1990) </li></ul><ul><li>genus/species named 1993 </li></ul><ul><li>morphology similar to Acanthamoeba </li></ul><ul><li>many Acanthamoeba GAE cases retrospectively assigned to Balamuthia </li></ul><ul><ul><li>as of 1997 63 cases of Balamuthia (30 in U.S.) </li></ul></ul><ul><li>thus far only identified post-mortem </li></ul><ul><li>environmental source not yet identified </li></ul>
  • 13. Recavarren-Arce et al (Human Path. 30:269, 1999) <ul><li>10 autopsies (1985-97) of Balamuthia cases in Peru </li></ul><ul><li>all healthy and all died within days or weeks of neurological symptoms </li></ul><ul><li>primary lesions: 8 nasal, 3 dermal </li></ul><ul><li>questioned hematogenous dissemination in both Acanthamoeba and Balamuthia </li></ul><ul><ul><li>no intravascular ameba (this study and literature) </li></ul></ul><ul><ul><li>perivascular infiltration frequently observed </li></ul></ul><ul><ul><li>propose perivascular route from primary mucosal lesion </li></ul></ul>
  • 14. Red Tides <ul><li>‘ blooms’ of dinoflagellates </li></ul><ul><ul><li>phyto- and zooplankton </li></ul></ul><ul><ul><li>usually monospecific </li></ul></ul><ul><li>rapid population increase </li></ul><ul><ul><li>nutrients, lack of grazing, sunlight, etc </li></ul></ul><ul><li>long cyst survival in some species </li></ul><ul><li>Increasing Incidence </li></ul><ul><li>better monitoring (seafood, aquaculture) </li></ul><ul><li>coastal pollution/nutrients </li></ul><ul><ul><li>agricultural wastes/fertilizers </li></ul></ul><ul><li>long distance shipping </li></ul>
  • 15. <ul><li>deplete oxygen  dead zones </li></ul><ul><li>produce toxins  fish kills </li></ul><ul><li>accumulated dinoflagellate toxins pass up the food chain </li></ul><ul><ul><li>'Ciguatera' </li></ul></ul><ul><ul><li>‘ shellfish’ poisoning </li></ul></ul>Potential Impact of Red Tides
  • 16. Pfiesteria piscicida <ul><li>effects observed in late 1980’s (named 1996) </li></ul><ul><ul><li>fisherman and swimmers complaining of rashes, lesions, respiratory and neurological problems </li></ul></ul><ul><ul><li>massive fish kills in east coast estuaries </li></ul></ul><ul><li>complex life cycle (at least 24 morphological forms) </li></ul><ul><li>Human Exposure to Pfiesteria Aerosols </li></ul><ul><li>narcosis/disorientation </li></ul><ul><li>respiratory distress/asthma-like </li></ul><ul><li>stomach cramping/nausea/vomiting </li></ul><ul><li>eye irritation/blurred vision </li></ul><ul><li>erratic heart beat (weeks) </li></ul><ul><li>sudden rages/personality changes </li></ul><ul><li>short term memory loss </li></ul>
  • 17. Why produce toxins ? <ul><li>accidental chemical affinity </li></ul><ul><li>self-defense (zooplankton, grazers) </li></ul><ul><li>ambush-predator life style </li></ul><ul><li>culture filtrates induce open ulcerative sores, hemorrhaging and death in fish </li></ul><ul><li>at least two toxins </li></ul><ul><ul><li>heat-stable, water-soluble toxin (fish become moribund within seconds and die within minutes) </li></ul></ul><ul><ul><li>lipophilic compound (causes the epidermis to slough off) </li></ul></ul>Pfiesteria Toxins

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