Improved subtyping affords better discrimination of Trichomonas gallinae strains and suggests hybrid lineages

• Published in: Infection, genetics and evolution Vol. 73; pp. 234 - 241
• Main Authors: Alrefaei, Abdulwahed F., Gerhold, Richard W., Nader, Johanna L., Bell, Diana J., Tyler, Kevin M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2019
• Subjects: Animals; Bird Diseases - epidemiology; Bird Diseases - parasitology; Birds - parasitology; Canker; DNA, Protozoan - genetics; Frounce; Gene Expression Regulation, Enzymologic; Hybrid; Hybridization, Genetic; Hydrogenase - genetics; Hydrogenase - metabolism; Iron-Sulfur Proteins - genetics; Iron-Sulfur Proteins - metabolism; Phylogeny; Protozoa; Ribotyping; Subtyping; Trichomonas - classification; Trichomonas - genetics; Trichomonas Infections - epidemiology; Trichomonas Infections - parasitology; Trichomonas Infections - veterinary; Trichomonosis; United States - epidemiology; United States; Frounce; Protozoa; Ribotyping; Canker; Hybrid; Trichomonosis; Subtyping
• ISSN: 1567-1348; 1567-7257
• DOI: 10.1016/j.meegid.2019.05.007

Trichomonas gallinae is a protozoan pathogen that causes avian trichomonosis typically associated with columbids (canker) and birds of prey (frounce) that predate on them, and has recently emerged as an important cause of passerine disease. An archived panel of DNA from North American (USA) birds used initially to establish the ITS ribotypes was reanalysed using Iron hydrogenase (FeHyd) gene sequences to provide an alphanumeric subtyping scheme with improved resolution for strain discrimination. Thirteen novel subtypes of T. gallinae using FeHyd gene as the subtyping locus are described. Although the phylogenetic topologies derived from each single marker are complementary, they are not entirely congruent. This may reflect the complex genetic histories of the isolates analysed which appear to contain two major lineages and several that are hybrid. This new analysis consolidates much of the phylogenetic signal generated from the ITS ribotype and provides additional resolution for discrimination of T. gallinae strains. The single copy FeHyd gene provides higher resolution genotyping than ITS ribotype alone. It should be used where possible as an additional, single-marker subtyping tool for cultured isolates. •We provide validation for the two typing loci widely used for avian trichomonosis (e.g. Trichomonas gallinae) as an alphanumeric subtyping scheme which facilitates strain identification and source tracking.•To do so we rescreen the archived panel of DNA from North American (USA) birds used initially to establish the ITS ribotypes using Iron hydrogenase (FeHyd) gene sequences to provide an improved resolution for strain discrimination.•Thirteen novel subtypes of T. gallinae using FeHyd gene as the subtyping locus are described.•Although the phylogenetic topologies derived from each single marker are complementary, they are not entirely congruent. This may reflect the complex genetic histories of the isolates analysed which appear to contain two major lineages and several that are hybrid.•This new analysis consolidates much of the phylogenetic signal generated from the ITS ribotype and provides additional resolution for discrimination of T. gallinae strains.