NAEGLERIA FOWLERI Flashcards
Common associated disease or condition name:
Primary amebic meningoencephalitis (PAM)
is the only ameba with three
known morphologic forms—ameboid trophozoites, flagellate (pertains to Protozoa that move by
means of flagella) forms, and cysts
Naegleria fowleri
The typical motility that is seen is accomplished by jerky movements or spinning.
Naegleria fowleri flagellate
Microscopic examination of ______________________(CSF) is the method of choice for the recovery of N. fowleri ameboid trophozoites
cerebrospinal fluid
Clinical specimens may be cultured. N. fowleri ameboid trophozoites show a characteristic trailing effect when placed on agar plates that have been previously inoculated with _____________________.
gram-negative bacilli
The ameboid trophozoites transform into flagellate trophozoites _______ after
being transferred to water from a tissue or
culture.
in vitro
The flagellate trophozoites do not divide
but rather lose their __________ and convert back into the ameboid form, in which reproduction resumes.
flagella
defined as a diagnostic sign for meningitis, where the patient is unable to fully straighten his or her leg when the hip is flexed at 90 degrees because of hamstring stiffness
Kernig’s sign
___________________ damage the cell wall of Naegleria, inhibiting the biosynthesis of ergosterol and resulting in increased membrane permeability, which causes nutrients to leak out of the cells.
Amphotericin B and miconazole
__________ inhibits RNA synthesis in
the amoeba by binding to beta subunits of DNA-dependent RNA polymerase, which in turn blocks RNA transcription. A
Rifampicin
The first case of PAM was reported by
Carter and Fowleri
One noteworthy species of Naegleria that
could possibly infect humans in the future is
known as
N. australiensis
method designed to aid in taxonomic classification
DNA restriction fragment length polymorphism (RFLP)
Transformation from the ______________ to _____________ form may facilitate more rapid movement toward food sources.
trophozoite to the flagellate
There are two forms of trophozoites of
Naegleria fowleri: _____________ & _____________, only the former of which is found in humans
ameboid and ameboflagellate
_____________ are thermophilic organisms
which thrive best in hot springs and other warm aquatic environments.
Naegleria spp.
The trophozoites replicate by ____________
(nuclear membrane remains intact) and can turn into temporary non-feeding flagellated forms, which usually revert back to the trophozoite stage.
promitosis
Trophozoites infect humans or animals
by penetrating the nasal mucosa and migrating to the brain via the _____________ nerves.
olfactory
Therefore, in contrast to Acanthamoeba which is largely an ____________ organism, N. fowleri is considered a true pathogen.
opportunistic
The ______________ of the
olfactory neuroepithelium are thought to
phagocytose the amebae and transport these through the cribriform plate and into the brain.
sustentacular cells
Characteristic cerebrospinal fluid
findings include _____________________________________________
elevated white blood cell count with neutrophilic predominance, high protein, and low glucose
Post-mortem examination of infected brain
shows _________________, particularly of
the olfactory bulbs, congestion and edema of
neural tissue.
hemorrhagic necrosis
Death usually occurs as a result of ______________________ as a result of increased intracranial pressure
cerebral or cerebellar herniation
____________ produces deleterious changes in the nucleus and mitochondria of the ameba, decreases the number of food vacuoles, and increases the formation of autophagic vacuoles. Ameba exposed to _______________ exhibit decreased pseudopod formation and form blebs on the plasma membrane
Amphotericin B
