title: Molecular characterization of Histomonas meleagridis and other parabasalids in the United States using the 5.8S, ITS-1, and ITS-2 rRNA regions.
abstract: Extracted DNA from 28 Histomonas meleagridis -infected avian tissue samples from multiple hosts and geographic locations was analyzed for variation in the 5.8S rRNA and the flanking internal transcribed spacer regions (ITS 1 and ITS 2). Samples were amplified by polymerase chain reaction, sequenced, and compared with known sequences from GenBank accessions of H. meleagridis and other related protozoa. The analyses revealed significant genetic variation within H. meleagridis sequences and suggested the possibility of multiple genotypes within the samples or a possible misdiagnosis. Related protozoa found in some samples were mostly identified as Tetratrichomonas spp. However, 1 sample had a 93% identity to Simplicimonas similis , a newly described organism, suggesting the possibility of a new pathogen in poultry. A phylogenetic tree analyzing the 5.8S and flanking ITS regions was inconclusive and we were unable to resolve all H. meleagridis into a single grouping. In contrast, a tree constructed only on the 5.8S rRNA grouped all but 1 H. meleagridis sample into 1 clade, including GenBank accessions submitted from Europe. This suggests that the 5.8S region alone is more reliable in identifying H. meleagridis than are the combined 5.8S and flanking ITS regions. There was no correlation between genotypes and host species or geographic location, suggesting that H. meleagridis moves freely between multiple avian species in the sampled regions.
authors.affiliation: Department of Poultry Science, College of Agriculture and Environmental Sciences, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Lori
authors.initials: L
authors.lastname: Lollis
authors.forename: Richard
authors.initials: R
authors.lastname: Gerhold
authors.forename: Larry
authors.initials: L
authors.lastname: McDougald
authors.forename: Robert
authors.initials: R
authors.lastname: Beckstead
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000469:parasitology*; D016054:DNA, Protozoan / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D046094:Galliformes / Q000469:parasitology*; D014644:Genetic Variation; D005838:Genotype; D056900:Parabasalidea / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011529:Protozoan Infections, Animal / Q000469:parasitology*; D012335:RNA, Ribosomal / Q000235:genetics*; D012340:RNA, Ribosomal, 5.8S / Q000235:genetics; D016415:Sequence Alignment / Q000662:veterinary; D014481:United States
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012335:RNA, Ribosomal; D012340:RNA, Ribosomal, 5.8S