Parascaris equorum


Parascaris equorum is a large conspicuous worm. The females may be as large as 50 cm in length and 8 mm in diameter. Males are smaller, ranging from 15 to 28 cm long.

The mouth opening is typically ascarid with three prominent lips. Each lip is divided into two parts,  anterior(A) and posterior(B) by a groove(G) along the medial surface.

Its predilection site is the small intestine of equines, including zebra. In heavy infections Parascaris may be responsible for gut impactions and ruptures leading to a fatal peritonitis. The black arrow points to a hole in the small intestine resulting from a rupture along the line of the mesenteric attachment caused by pressure from the mass of worms.

Infections are found mainly in nursing and weaned foals less than a year old.  


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