[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 8 The Nematodes
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of the host. Children infected with T. trichiura
usually present with symptoms resembling those
of ulcerative colitis. An infection of as few as 200
worms may cause a child to develop chronic
dysentery, severe anemia, and possibly growth
retardation. It is interesting to note that in treated
children, catch-up growth usually occurs. In
addition, increased rectal prolapse and peristalsis
are common in infected children. Infected adults
experience symptoms that mimic those of inflammatory
bowel disease. Common symptoms found
in infected persons include abdominal tenderness
and pain, weight loss, weakness, and mucoid or
bloody diarrhea.
Treatment
Mebendazole or albendazole are considered as
the treatment of choice for whipworm
infections.
Prevention and Control
The spread of T. trichiura infections may be
halted by exercising proper sanitation practices,
especially avoidance of defecating directly into
the soil, using feces as a fertilizer, and placing
potentially infective hands into the mouth and
prompt and thorough treatment of infected
persons, when indicated. Educating children and
aiding institutionalized mentally handicapped
persons in their personal hygiene and sanitation
practices is crucial to eradicate whipworm infections
completely.
Quick Quiz! 8-7
Trichuris trichiura eggs are characterized by the presence
of which of the following? (Objective 8-10A)
A. Triple-layer cell wall
B. Flattened side
C. Hyaline polar plugs
D. Prominent cytostome
Quick Quiz! 8-8
Of the following choices, the best laboratory diagnosis
technique for the recovery of Trichuris trichiura
eggs is which of the following? (Objective 8-9)
A. Zinc sulfate flotation
B. Modified acid-fast stain
C. Ethyl acetate concentration
D. Wright-Giemsa stain
Quick Quiz! 8-9
Children infected with Trichuris trichiura commonly
suffer from: (Objective 8-7)
A. Mental confusion
B. Hemoglobinuria
C. Severe anemia
D. Rectal prolapse
Ascaris lumbricoides
(as’kar-is/lum-bri-koy’deez)
Common names: Large intestinal roundworm,
roundworm of man.
Common associated disease and condition
names: Ascariasis, roundworm infection.
Morphology
Unfertilized Eggs. The typical oblong, unfertilized,
Ascaris lumbricoides egg characteristically
measures 85 to 95 µm by 38 to 45 µm (Fig.
8-6; Table 8-5). A thin shell protects the inner
amorphous mass of protoplasm. The egg is
usually corticated (i.e., the egg possesses an outer
mammillated, albuminous coating). Variations in
shape, size, and cortication may also be seen, as
in Figure 8-6B.
Fertilized Eggs. The fertilized A. lumbricoides
egg is more rounded than the unfertilized egg,
usually measuring 40 to 75 µm by 30 to 50 µm
(Figs. 8-7 and 8-8; Table 8-6). Fertilization of the
egg transforms the amorphous mass of protoplasm
into an undeveloped unicellular embryo.
A thick nitrogen-containing polysaccharide