Lethal infection caused by Tetratrichomonas gallinarum in black swans (Cygnus atratus)

Shengyong Feng,Hongxuan He,Yutian Wang,Qiaoxing Wu,Fubing Luo,Shuyi Han,Han Chang

doi:10.1186/s12917-021-02894-x

Abstract

BackgroundTetratrichomonas gallinarum is parasitic protozoa with a wide host range. However, its lethal infection is rare reported.Case presentationHere, we described the first lethal cases of T. gallinarum infection in black swans in China. Five black swans died within a week in succession without obvious symptoms except mild diarrhea. At necropsy, severe lesions were observed in caeca with thickened caecal walls and hemorrhages in the mucosa. A large number of moving trophozoites were found in the contents of the cecum by microscopic examination. The livers were enlarged with multiple bleeding spots on the surface. Histopathology of the livers showed mononuclear cell infiltration and moderate hyperplasia of fibrous tissue. The histopathology of the cecum showed that the villi of the cecum were edematous. Finally, the presence of T. gallinarum was determined by specific PCR andin-situ hybridization assay. Additionally, common pathogens that can cause similar symptoms were excluded.ConclusionsThe death of the black swan was caused by T. gallinarum, suggesting that the parasite might be a new threat to the Cygnus birds.

Highlights

Tetratrichomonas gallinarum is parasitic protozoa with a wide host range
The death of the black swan was caused by T. gallinarum, suggesting that the parasite might be a new threat to the Cygnus birds
* Correspondence: hehx@ioz.ac.cn 1National Research Center for Wildlife Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxilu, Chaoyang District, Beijing 100101, PR China Full list of author information is available at the end of the article

Summary

Introduction

Tetratrichomonas gallinarum is parasitic protozoa with a wide host range. its lethal infection is rare reported.Case presentation: Here, we described the first lethal cases of T. gallinarum infection in black swans in China. Conclusions: The death of the black swan was caused by T. gallinarum, suggesting that the parasite might be a new threat to the Cygnus birds. We described the first fatal case of black swans (Cygnus atratus) associated with T. gallinarum infection in China, and the threat of the protozoa to Cygnus birds must be considered.

Results

Conclusion