encephalitis caused by naegleria fowleri and others

8/7/2019 Encephalitis caused by Naegleria fowleri and others

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Encephalitis caused by Naegleria

fowleri and others amoebas.

Guillermo Roberto Guevara Morales



Naegleria fowleri

Flagellate stage

Trophozoite

Cyst stage

Different stages of Naegleria fowleri

�Is a free-living amoebae.

�typically found in warm bodies

of fresh water, such as ponds,lakes, rivers, and hot springs.

� N. fowleri can invade and

attack the human nervous

system.

�An infection will nearly always

result in the death of the victim.



others amoebas

� Acanthamoeba

� A. castellani

� A. polyphaga

� Balamuthia

� B. mandrillaris



History

� Between 1958 and 1961, Clubertsonsuggested that free-living amoebae may causealterations in humans

� Fowler and Carter first described humandisease caused by amebo-flagellate inAustralia in 1965

� In 1966, Butt reported the first case of Nfowleri meningoencephalitis .



Lifecycle



Pathophysiology

1. penetrate the submucosal

nervous plexus, cross the

cribriform plate, and gainaccess to the subarachnoid

space

2.The presence of protein and glucose

in the (CSF) supports the growth of

amebae

3.The invasive trophozoites

are highly phagocytic and

ingest RBCs and brain tissue,

resulting in severe

hemorrhagic necrosis of the

involved brain.



CLINICAL MANIFESTATIONS

� Abrupt onset

� IP: 2-5 days

� Fever

� headache

� disturbances of smell and taste.

� signs of meningoencephalitisin± nuchal rigidity

± Lethargy

±

Confusion± altered level of consciousness.

± Seizures are common.

� Death occurs within a week of onset of symptoms



Granulomatous amebic encephalitis

caused by Acanthamoeba

� Insidious onset

� progressionof manifestations occurring weeksto months after exposure

� personality changes

� Seizures

� Headaches

� nuchal rigidity

� ataxia



diagnosis

� Cerebrospinal fluid test satined with Wright,

Giemsa o H&E.

� Asimple agar and E. Coli culture

� Brain biopsy

� Additional methods

±

PCR± CT

CSF protein levels are

elevated.

CSF glucose levels are

within the reference range

or reduced.CSF WBC count is elevated

(400-26,000 cells/µL).

CSF RBC count is high.

CSF Gram stain results are

negative for bacteria.



References

� WebMD (May 29, 2008). Brain eating amoeba strikes in summer.Retrieved May 14, 2009, fromhttp://www.webmd.com/news/20080529/brain-eating-amoeba-strikes-in-summer

� Mayoclinic.com (2009). Naegleria fowleri. Retrieved May 16, 2009,

from http://mayoclinic.com/health/naegleria-infection/DS01066� CDC (2009). Parasitic disease information. Retrieved May 16, 2009,

fromhttp://www.cdc.gov/ncidod/dpd/parasites/naegleria/factsht_naegleria.htm

� CDC (2009). Naegleria infection. Retrieved May 17, 2009, fromhttp://www.cdc.gov/ncidod/dpd/parasites/naegleria/moreinfo_naegleria.htm#reports

� CDC (2009). Naegleria fowleri in well water. Retrieved May 24,2009, from http://www.cdc.gov/eid/content/14/9/1499.htm



Treatment

� Amphotericin B.

±

miconazole IV

± rifampin

± Sulfonamides

± chloramphenicol

± tetracycline

encephalitis caused by naegleria fowleri and others

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