Page 158 - parasitology for medical and clinical laboratoryprofessionals

138 CHAPTER 6

cellophane tape over a tongue blade into the perianal
folds late at night or before daylight affords the best op- MICROSCOPIC DIAGNOSTIC
portunity of recovering evidence of infection. The slide FEATURE
is then examined microscopically for the typical ova and
four to six slides collected at different times should be
performed before ruling out the infection. Occasionally General Classification—Pinworm,
the adult worm will also be found on the slide along with (Nematode egg)
the characteristic ova. Organism Enterobius
vermicularis
Specimen Required Scotch tape prep
for eggs or worms
Stage Egg
MICROSCOPIC DIAGNOSTIC Size Ova are 50–60 μm 3
FEATURE 20–30 μm
Shape Flattened on one
side, with a C-shaped
General Classification—Pinworm, embryo in the egg
larval form Shell Thick, colorless

Organism Enterobius vermicularis Other Features Partially embryonated
eggs may develop to
Specimen Required Feces
an infectious stage
Stage Diagnostic specimens within approximately
include ova or adult six hours
female “worms”
E. vermicularis
Size Worms—Male adult
range from 2–5 mm Ovum, embryonated
with curved posterior Delmar/Cengage Learning
and the adult female
ranges from 8–13 mm
with long pointed tail
and three cuticle lips
Shape Long, pointed, and
pinlike morphology Treatment and Prevention
Motility Sluggish motility
when viewed in fecal The physician will most likely request a procedure to
specimen test a sample of the patient’s feces to make a positive
Other Features May also be found in identi fication of pinworms as the cause for symptoms of
vaginal area of female infection. Medication is available to kill the worms and
children; occasionally this is usually prescribed for the infected person and all
female adults along members of the household. Usually one dose is followed
with eggs may be
found on Scotch up with a second dose 2 weeks later to take care of any
tape prep surviving worms. Although safe for humans, a prescrip-
tion from the physician is required before starting the
E. vermicularis medication. A repeat preparation should be examined
Delmar/Cengage Learning tion, regardless of whether they are experiencing symp-
Adult Female worm following completion of treatment to ensure complete
eradication. All family members should take the medica-

toms, because the condition is quite contagious and some
are asymptomatic, showing no evidence of the common
symptoms and signs of infection. Treatment for relieving