Avian Candidiasis Study Guide

Overview and Clinical Importance

Candidiasis (also known as thrush, sour crop, or crop mycosis) is a common opportunistic fungal infection affecting the gastrointestinal tract of birds, caused primarily by the yeast Candida albicans. This condition is one of the most frequently encountered mycotic diseases in avian practice and represents an important topic on the NAVLE examination.

Candida species are regarded as commensal organisms that normally reside in the skin, digestive tract, and urogenital systems of healthy birds in small numbers. Disease occurs when host immune defenses are compromised, allowing opportunistic overgrowth. Understanding the predisposing factors, clinical presentation, diagnosis, and treatment of avian candidiasis is essential for veterinary practitioners and represents testable material for board examinations.

Etiology and Pathogenesis

Causative Organisms

The genus Candida comprises approximately 200 species, but only a small number are pathogenic in birds. Candida albicans is the most common isolate from clinical cases, accounting for the vast majority of avian candidiasis infections. Other species that may cause disease include: