A distinctive aphthous ileitis linked to Ancylostoma caninum

Area of Science:

• Gastroenterology
• Parasitology
• Epidemiology

Background:

• Ileal ulceration is frequently diagnosed during colonoscopies in northeastern Australia.
• This coincides with reports of painful enteritis caused by Ancylostoma caninum, the dog hookworm.

Purpose of the Study:

• To describe the morphology and prevalence of ileal ulcers.
• To investigate the causative agent of these ulcers, particularly the role of A. caninum.

Main Methods:

• Analysis of 182 patients with aphthous ileitis.
• Morphological and histological examination of ileal tissue.
• Serological testing for A. caninum infection.
• Correlation of diagnosis rates with patient demographics (dog ownership) and climate.

Main Results:

• A distinctive aphthous ileitis with villous hemorrhage was observed in 4.7% of ileal examinations annually.
• Eosinophilic enteritis was a characteristic histological finding.
• A. caninum infection was linked via serology and direct worm retrieval in some cases.
• Patients with ulcers were more likely to own dogs (53% vs. 43%).
• Diagnosis rates peaked in warmer months, with fewer cases in winter.
• Pain was a significant symptom, reported by 49% of ulcer patients versus 28% of controls.
• Elevated blood eosinophils, immunoglobulin E, and serological markers were noted in affected patients, especially those with pain.
• Subclinical ulceration was identified in 3.2% of patients undergoing colonoscopy for other reasons.

Conclusions:

• A distinct form of aphthous ileitis characterized by tissue eosinophilia has been identified.
• Canine hookworm (A. caninum) infection is the likely cause of this condition.
• A. caninum infection appears to be common in the region, with painful enteritis developing rarely due to hypersensitization.