[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 7 Miscellaneous Protozoa
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urogenital tract. However, the incidence of such
extraintestinal infections is rare.
Treatment
Two factors play an important role in determining
the prognosis of patients infected with B.
coli, the severity of the infection and the patient’s
response to treatment. Asymptomatic patients
and those suffering from chronic disease typically
have a good chance of recovery. There are
two medication choices for the effective treatment
of B. coli infections, oxytetracycline (Terramycin)
and iodoquinol. Metronidazole (Flagyl)
may also be used to treat infected patients.
Prevention and Control
Personal hygiene and proper sanitary conditions
are effective measures for B. coli prevention and
control. Until the questions surrounding the pig’s
role in transmitting B. coli are completely understood,
the pig should be considered as a possible
source of infection and proper precautions should
be exercised when handling and dealing with
pigs and their feces.
Notes of Interest and New Trends
The B. coli trophozoite is often referred to as
resembling a sac in shape. As a reflection of this
shape, the organism was named Balantidium,
which means “little bag.”
It is estimated that 63% to 91% of pigs harbor
B. coli. In addition, pigs also carry Balantidium
suis, a parasite that is morphologically identical
to B. coli but does not appear to cause human
infections. Unsuccessful attempts have been
made to infect humans purposely with B. suis.
Because the incidence of B. coli is low in the
population as a whole and in those who have
regular contact with pigs, it has been suggested
that humans have a relatively high natural resistance
to this organism.
Quick Quiz! 7-2
Which structure is always visible in the stained cyst
and troph of Balantidium coli? (Objective 7-9A)
A. Macronucleus
B. Micronucleus
C. Cilia
D. Ingested bacteria
Quick Quiz! 7-3
The life cycle of Balantidium coli and clinical symptoms
are similar to that of which of the following?
(Objectives 7-11)
A. Isospora belli
B. Entamoeba histolytica
C. Crytosporidium parvum
D. Giardia intestinalis
Quick Quiz! 7-4
Which two factors play an important role in the prognosis
of a Balantidum coli infection? (Objective 7-7A)
A. How infection occurred and duration of the
infection
B. Presence of coinfection and duration of the
infection
C. Severity of infection and response to treatment
D. Immunocompetent status and severity of
infection
Isospora belli
(eye”sos’puh-ruh/bell-eye)
Common associated disease and condition
names: Isosporiasis.
Morphology
Oocysts. The oval transparent oocyst of Isospora
belli ranges in size from 25 to 35 µm long
by 10 to 15 µm wide, with an average of 30 by
12 µm (Fig. 7-7; Table 7-3). The developing