<div>Background: Trichomonas gallinae is a flagellated protozoa, infects the upper digestive system of pigeon and causing a condition called canker, characterized by development of granulomatous lesions in the buccal cavity, crop, proventriculus, gizzard and liver of affected birds causing mortality upto 90% in squabs. Systemic research on prevalence and pathology of T. gallinae in pigeons are scant in India. The present work was carried out to document the prevalence and pathology of T. gallinae in pigeons of Assam. 
 
Methods: During the one- year study period, throat swab samples were collected from households, market places and temple premises in 4 districts of Assam. A total of 324 birds were examined by wet mount and Giemsa staining methods for detection of T. &nbsp;gallinae. Naturally died carcasses were studied for gross and histopathological alteration in different organs. 
 
Result:&nbsp;In the present study prevalence of T. gallinae was found 26.85% and squabs were highly susceptible with 56.25 percent. &nbsp;Sex wise, comparatively higher prevalence was observed in females (33.54%) than in the males (20.48%). Seasonality study revealed highest prevalence during winter. Gross pathological alteration characterized by yellowish white caseo-necrotic haemorrhagic lesion in the upper digestive tract beginning with the oral cavity and lesions also found in liver and lungs. Histopathological alteration also recorded in different organs. In the liver sinusoidal congestion and kupffer cell hyperplasia were observed. Infiltration of polymorphonuclear cells in the thickened inter alveolar space of lungs also recorded. Further study is required to identify the prevalent strains of T. gallinae on the basis of pathogenicity in this geographic region and immunology of T. gallinae in pigeons and other hosts remain to be explored.</div>

Prevalence and Pathology of Trichomonas gallinae in Domestic Pigeon (Columba livia domestica) of Assam, India