Avian Trichomoniasis Study Guide

Overview and Clinical Importance

Avian trichomoniasis is a parasitic protozoal disease caused by Trichomonas gallinae, a flagellated protozoan that primarily affects the upper digestive tract of birds. The disease is known by several synonyms depending on the species affected: canker in pigeons and doves, frounce in raptors, and roup in domestic poultry. This disease represents one of the most significant infectious diseases in columbiform birds and is considered the most important disease of mourning doves in North America.

Trichomoniasis has historical significance, with written records dating back to the 1500s. The disease has been implicated in population declines of European turtle doves and the extinction of the North American passenger pigeon. In 2005, the disease emerged in British finches, causing epidemic spread throughout Great Britain and Europe with significant population declines in greenfinches and chaffinches.

Etiology and Organism Characteristics

Taxonomic Classification

Trichomonas gallinae belongs to the family Trichomonadidae, order Trichomonadida, class Trichomonadea, and phylum Parabasalia. Two additional species have been recently recognized: Trichomonas stableri (found in Pacific coast band-tailed pigeons) and Trichomonas gypaetinii (found in scavenging birds of prey such as vultures).