Molecular characterization of Histomonas meleagridis in clinical samples of chickens from Eastern China

Abstract

Histomonas meleagridis (H. meleagridis) is a protozoan parasite that may cause histomoniasis, a disease of special importance to the poultry industry and public health. The molecular characterization of H. meleagridis in China has not been established. The 5.8S and flanking ITS regions were amplified by polymerase chain reaction from 15 liver samples of chickens which were preliminarily diagnosed with H. meleagridis infection by observing clinical symptoms and macroscopic changes in the organs in Eastern China between 2012 and 2013. The obtained sequences were aligned and compared with other known sequences of H. meleagridis and related protozoan species based on ITS1-5.8S rRNA-ITS2 or 5.8S rRNA region alone. Out of the 15 obtained sequences, 8 sequences were identified as H. meleagridis and were grouped into five clades, suggesting the possibility of multiple genotypes within the samples. Among the remaining 7 sequences, 4 sequences were more related to Trichomonas and 3 sequences were more related to Tetratrichomonas, which suggests the possibility of misdiagnosis or coinfection with other protozoans. Therefore, there is obvious genetic diversity of H. meleagridis based on the 5.8S and flanking ITS regions, which suggests the presence of different genotypes in chickens from Eastern China.