Trichuriasis

Introduction

 

Agent

 

History of Discovery

 

Symptoms

 

Diagnosis and Treatment

 

Epidemiology

 

Links and References

 

Contact

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Agent

Turchuriasis is caused by Trichuris trichiura, a parasitic nematode.

 

Taxonomy
Class: Adenophorea

Order:Stichosmida
Family: Trichocephaloidea


Synonyms
Whipworm

Morphology

As 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.

Picture of adult male and female worms, courtesy of Dr. Scott Smith

picture of T. trichiura egg (CDC)

Egg 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.

 


 

Life Cycle

Unembryonated eggs 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 day!