Veterinary Parasitology: The Practical Veterinarian - CX.com

Parasites of the Gastrointestinal Tract I 111
bovine ostertagiosis important in weanling and yearling
classes; poor nutrition and other stress factors may
contribute to clinical disease in adult animals.
• Both larval and adult worms may be pathogenic; the
clinical picture produced depends on the composition
of the parasites present, how many are present,
age and nutritional status of the host, and a variety
of other factors.
• In mixed infections (the rule rather than the exception),
the general pathologic condition is a hyperplastic
gastritis and catarrhal enteritis.
• Clinical signs may include diarrhea, rough hair coat,
weight loss or decreased weight gain, anemia, inappetence.
• Ostertagiosis in cattle
Development and emergence of larvae from gastric
glands cause cellular destruction; loss of parietal
cells causes decreased production of HCl
leading to increased abomasal pH; protein digestion
ceases when pH is over 4.5–5.0.
Increased pH also results in loss of bacteriostatic
effect and failure to activate pepsinogen to pepsin.
Cellular destruction results in disruption of junctions
leading to enhanced permeability; plasma
proteins leak into abomasum resulting in hypoalbuminemia,
fluid accumulation in abomasal
walls, and peripheral edema (most often manifested
as submandibular edema or “bottle jaw”).