Oesophagostomum species


Morphology and species

Members of this genus are known as the "nodular worms" because they are associated with nodule formation in the intestines of their hosts. They are common parasites of ruminants, pigs, primates and rodents. The species found in domestic animals are often of pathogenic importance:

Nematode Species

Host Species Predilection site

Oesophagostomum radiatum

cattle large intestine
Oesophagostomum columbianum cattle large intestine
Oesophagostomum venulosum

sheep and goats

large intestine

Oesophagostomum dentatum


distal colon

Oesophagostomum quadrispinulatum


cecum and proximal colon

Adults are 1-2cm long. The buccal capsule is relatively shallow and the head end is distinctive because of the cephalic inflations of the cuticle. Males have a bursa and the egg passed by the female worms is a strongyle-type egg

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Oesophagostomum radiatum with cuticular modifications at the anterior end:
A = cephalic vesicle
B = cervical vesicle
C = cervical alae
Image courtesy of Merial Inc
Oesophagostomum columbianum - the posterior end showing the copulatory bursa (A) containing bursal rays.
Image courtesy of Merial Inc
Oesophagostomum dentatum - adult worms with a pin to show comparative sizes. The female (left of the pin) is the thicker of the two. The specimen to the right of the pin is a male L4 with a dorsally curved tail.
Image courtesy of Dr. E.J. Batte



Parasites and Parasitic Diseases of Domestic Animals
Dr. Colin Johnstone (principal author)
Copyright 1998 University of Pennsylvania
This page was last modified on January 24, 2000