Oesophagostomum species

Clinical signs

Acute infections are the result of larval penetrations of the intestinal mucosa during the prepatent period. Diarrhea is the usual clinical sign in these cases and may be accompanied by weight loss and submandibular edema ("bottle jaw") in ruminants.

Chronic oesophagostomosis is most common in sheep and is due to repeated infections. Intermittent diarrhea accompanied by loss of appetite are the usual clinical signs and in more severe chronic cases sheep may become emaciated and anemic.

Infections in pigs may produce a range of clinical signs including acute diarrhea and a syndrome in adult females called the "thin sow syndrome" - a chronic infection  with periodic acute flare-ups due to the resumption of development of hypobiotic larvae during spring farrowing. This syndrome shows as weight loss after farrowing and reduced milk production with adverse effects on the growth of litters.


In acute infections clinical signs will occur during the prepatent period and diarrhea will occur without strongyle-type eggs being seen in the feces of infected animals. In chronic infections, strongyle-type eggs will be commonly seen but are indistinguishable from eggs produced by other strongyle nematodes. Necropsies will show the classic nodular lesions throughout the small and large intestines

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Growing pigs (4-5 months old) with acute diarrhea due to a prepatent infection with Oesophagostomum dentatum

Strongyle-type eggs from a patent experimental infection with Oesophagostomum dentatum in pigs.



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