Turchuriasis is caused
by Trichuris trichiura, a parasitic nematode.
their common name suggests, adult worms resemble whips. They have
long, thin bodies with a tapered head and a thick posterior. This
is opposite what was originally believed, that their heads were thicker
than their tails. However, this morphology makes sense since the head
of the worm contains only an esophagus, while the posterior end contains
the intestines and reproductive organs. Adults are 3-5 cm in length
with the females slightly larger than the males. Adult worms can live
from 4-8 years in humans if the infection is left untreated.
of adult male and female worms, courtesy of Dr. Scott Smith
picture of T. trichiura egg (CDC)
morphology is important to note because egg identification in the
stool is the sole method of diagnosis. T. trichiura eggs have
a characteristic football shape with two plugged ends that resist
staining. Eggs are usually yellow brown when they are passed from
the stool and color can be seen in contrast to the clear polar plugs.
are passed through the stool of an infected individual. Under favorable
conditions of high humidity, sandy soil, and warm temperatures eggs develop
into the infectious, embryonated, stage in 15-30 days. When infectious
eggs are ingested, they hatch in the small intestine and then migrate
to the cecum and ascending colon. Adult worms wind their thin heads into
the epithelium of the large intestine while the thick posterior end protrudes
into the lumen. Even though this is manner of establishing itself is reminiscent
of the hookworm, blood loss from T. trichiura is slight.
After about 60 days, female whipworms begin to produce eggs. Females are
quite impressive and can lay anywhere between 1,000 to 20,000 eggs per