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 |
swine |
distal colon |
| Oesophagostomum quadrispinulatum |
swine |
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 |
