Detection of Pseudocyst Forms of Trichomonas muris in Rodents from Iran.

Background: Trichomonas muris is one of the most common protozoa diagnosed in rodents. The trichomonads are generally described as presenting only trophozoite form while pseudocyst is another morphological form of trichomonads identified among gastrointestinal and genitourinary trichomonads. We identified and described different shapes of T. muris pseudocysts and trophozoite in stool samples were collected from rodents including Merinos persicus , Mus musculus and Cricetulus migratorius .

Methods: In this cross-sectional study, stool samples from 204 trapped rodents were collected from Meshkin Shahr during Mar to Dec 2014. Samples were preserved in formalin 10% and PVA solution and transferred to Department of Medical Protozoology and Mycology, School of Public Health, Tehran University of Medical Sciences. Formalin-ether concentration method was used for the samples. The slides were stained with tri-chrome staining method and observed under light microscope.

Results: The trophozoites were classified as T. muris based on size (18 to 24 μm), presence of three anterior flagella, recurrent flagellum, undulating membrane, and axostyle in direct examination and stained slides with trichrome staining method. Fifty-five out of 204 (27%) rodents were infected with T. muris in which 51(25%) samples pseudocysts form were observed. The spherical bodies of pseudocyst with almost 8 μm size, contained internalized flagella, an undulating membrane with recurrent flagellum, axostyle, and costa were seen. The pseudocysts were more prevalent than trophozoite form and pseudocysts were found with different shapes in this study.

Conclusion: T. muris pseudocysts were found in stool samples of caught rodents for the first time in northwestern Iran.