Hamster Proliferative Ileitis (Wet Tail) Study Guide

Overview and Clinical Importance

Proliferative ileitis, commonly known as "wet tail," is the most significant gastrointestinal disease affecting Syrian hamsters (Mesocricetus auratus). This highly fatal enterocolitis is characterized by profuse watery diarrhea that causes wet, matted fur around the hindquarters and tail. The disease primarily affects weanling hamsters aged 3-10 weeks and carries an estimated mortality rate of approximately 90% without treatment. Even with aggressive therapy, prognosis remains guarded.

The primary causative agent is Lawsonia intracellularis, a gram-negative, obligate intracellular bacterium that infects the epithelial cells of the ileum. This organism causes hyperplasia of the intestinal crypts, leading to malabsorption and severe fluid loss. The disease is often precipitated by stress factors including weaning, transport, overcrowding, dietary changes, or high temperatures.

Etiology

Primary Causative Agent

Lawsonia intracellularis is a gram-negative, curved or vibroid-shaped, obligate intracellular bacterium measuring 1.25-1.75 micrometers in length. Key characteristics include: