Avian trichomoniasis caused by Trichomonas gallinae is a serious protozoan disease worldwide. The domestic pigeon (Columba livia domestica) is the main host for T. gallinae and plays an important role in the spread of the disease. Based on the internal transcribed spacers of nuclear ribosomal DNA of this parasite, a pair of primers (TgF2/TgR2) was designed and used to develop a PCR assay for the diagnosis of T. gallinae infection in domestic pigeons. This approach allowed the identification of T. gallinae, and no amplicons were produced when using DNA from other common avian pathogens. The minimum amount of DNA detectable by the specific PCR assay developed in this study was 15 pg. Clinical samples from Guangzhou, China, were examined using this PCR assay and a standard microscopy method, and their molecular characteristics were determined by phylogenetic analysis. All of the T. gallinae-positive samples detected by microscopic examination were also detected as positive by the PCR assay. Most of the samples identified as negative by microscopic examination were detected as T. gallinae positive by the PCR assay and were confirmed by sequencing. The positive samples of T. gallinae collected from Guangzhou, China, were identified as T. gallinae genotype B by sequencing and phylogenetic analyses, providing relevant data for studying the ecology and population genetic structures of trichomonads and for the prevention and control of the diseases they cause.

BackgroundTrichomonas gallinae is a protozoan parasite causing trichomonosis in many species of domestic poultry and birds world-wide. microRNAs (miRNAs) are a class of small non-coding RNAs that play key roles in gene regulation. However, no miRNAs have been characterized from T. gallinae.MethodsHere, we investigated the global miRNA profile of this parasite by high throughput sequencing technology, bioinformatics platform analysis and quantitative RT-PCR.ResultsThree miRNA candidates, with typical precursor stem-loop structures, were identified from 11.13 million raw sequencing reads. Three miRNAs, Tga-miR-1, Tga-miR-2 and Tga-miR-3 had no homologues in publically available miRNA databases, suggesting that they may be T. gallinae-specific. Tga-miR-2 and Tga-miR-3 occupied only one location each on the reference genome, while Tga-miR-1 was found at 3 locations.ConclusionsThe results of the present study provided a sound basis for the further understanding of gene regulation in this parasite of animal health significance, with the potential to inform the development of novel control reagents and strategies and also inform a more in-depth understanding of the evolution of miRNAs.

Domestic pigeon (Columba livia domestica) as the main host of Trichomonas gallinae plays an important role in the spread of T. gallinae, but limited information about the prevalence of T. gallinae in domestic pigeons in China is available. In the present investigation, a total of 319 domestic pigeons on seven commercial farms in Guangdong Province, Southern China were examined microscopically in freshly prepared wet mount between July 2009 and January 2010. T. gallinae was observed in 108 out of 319 pigeons, giving an overall prevalence of 33.9%. Among these flocks in this survey, the positivity in different farms varied ranging from 23.7 to 45.1% with no significant difference ( 2 = 5.602, P = 0.469). However, significant difference in the prevalence of pigeons with different ages was observed ( 2 = 11.59, P = 0.003). The results of the present survey revealed high prevalence of T. gallinae infection in pigeons, and so improved integrated strategies should be taken to control the spread of T. gallinae infection in pigeons in China.