[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

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CHAPTER 3 The Amebas
Quick Quiz! 3-24
The ameboid trophozoites of N. fowleri enter the
human body through all of the following routes
except: (Objective 3-5B)
A. Entry through the nasal mucosa
B. Inhalation of contaminated dust
C. Sniffing contaminated water
D. Ingesting contaminated food and drink
Quick Quiz! 3-25
Cytoplasm
No peripheral
chromatin
Pseudopods
(Acanthopodia)
Large karyosome
Size range: 12-45 m
Average size: 25 m
FIGURE 3-22 Acanthamoeba species trophozoite.
Practical measures for the control and prevention
of N. fowleri include which of the following? (Objective
3-7C)
A. Banning swimming at all times during the summer
months
B. Avoidance of chlorinating swimming pools and
hot tubs
C. Providing education and awareness in the medical
community
D. Avoidance of consuming contaminated food or
water prior to swimming
Acanthamoeba species
(ay-kanth’uh-mee’buh)
Common associated disease or condition names:
Granulomatous amebic encephalitis (GAE), Acanthamoeba
keratitis
Morphology
Trophozoites. The Acanthamoeba trophozoite
averages 25 µm, with a range of 12 to 45 µm
in size (Figs. 3-22 and 3-23; Table 3-15). Motility
is sluggish and there is little evidence of progressive
motility. Spinelike pseudopods, known as
acanthopodia, project outward from the base
of the organism. Acanthamoeba trophozoites
contain one nucleus, consisting of a large karyosome
similar to that of N. fowleri. Obvious
FIGURE 3-23 Acanthamoeba species trophozoite
showing typical thornlike acanthopodia (arrows) (iron
hematoxylin stain, ×1000). (Courtesy of WARD’S Natural
Science Establishment, Rochester, NY; http://wardsci.com.)
TABLE 3-15
Acanthamoeba species
Trophozoite: Typical
Characteristics at a Glance
Parameter
Description
Size range 12-45 µm
Motility
Sluggish, spinelike
pseudopods
Number of nuclei One
Karyosome
Large
Peripheral chromatin Absent
Cytoplasm
Granular and vacuolated