# Prevalence Study of Trichomonas gallinae in Domestic Pigeons in Northeastern Beijing and Experimental Model of Trichomoniasis in White King Squabs Measuring In Situ Apoptosis and Immune Factors in Crop and Esophagus

## TL;DR

This study examines how Trichomonas gallinae affects domestic pigeons, focusing on infection rates and immune responses in specific bird breeds.

## Contribution

The study introduces an experimental model to measure apoptosis and immune factors in pigeons infected with Trichomonas gallinae.

## Key findings

- Trichomonas gallinae infection leads to increased apoptosis in pigeon crops and esophagi.
- Immune factors like IL-1β and TGF-β show altered expression patterns post-infection.
- White King pigeons had the highest prevalence of Trichomonas gallinae infection.

## Abstract

Avian trichomonosis is a serious disease in pigeon production caused by Trichomonas gallinae. Previous research has described its morphology, epidemiology, diagnostic treatment and pathology, but there are only a few studies on the level of in situ apoptosis and immune factors in experimentally infected squabs. The prevalence of Trichomonas gallinae in five breeds ranged from 27.13% (White Carneau) to 43.14% (White King) in domestic pigeons in northeastern Beijing. By conducting an experimental model of trichomoniasis in White King squabs, measuring in situ apoptosis and immune factors in the crop and esophagus, we found that Trichomonas gallinae infection may lead to high mortality, trigger apoptosis and modulate immune-related factor expression in the crop and esophagus of pigeons.

Trichomonas gallinae (T. gallinae) is a flagellated protozoan and the causative agent of trichomoniasis, or canker, in birds. In the current study, the prevalence of T. gallinae was firstly investigated in five breeds. According to the results of the prevalence study, White King pigeons were selected as the experimental animals. A total of 135 White King squabs at one day of age were randomly divided into two groups and raised in separate isolators. The challenged group (N = 100) was challenged intranasally with 5 × 106 parasites/mL of the T. gallinae strain, and the control group (N = 35) was intranasally administered medium of equivalent volume. At 1, 2, 3 and 5 days post infection (DPIs), the crops and esophagi were collected for RNA extraction and formaldehyde fixation. The results showed that prevalence of T. gallinae in the five breeds ranged from 27.13% (White Carneau) to 43.14% (White King). After the challenge, mild microscopic lesions were observed in both tissues. Apoptosis rates were higher in the challenged group than in the control group at 2 and 5 DPIs in the crop and at 1, 2 and 7 DPIs in the esophagus. For both tissues, relative expression of IL-1β increased dramatically at the beginning and decreased at 5 DPIs, and TGF-β increased stably in the challenged group.