Date of Award

5-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Comparative and Experimental Medicine

Major Professor

Rebecca P. Wilkes

Committee Members

Richard W. Gerhold Jr., Stephen A. Kania, Scott C. Lenaghan

Abstract

Tritrichomonas foetus is a bovine and feline parasite and a porcine commensal. This organism is the causative agent of bovine and feline trichomonosis. In cattle, the parasite colonizes the urogenital tract and causes similar symptoms to those caused by Trichomonas vaginalis in humans. In cats, the parasite colonizes the gastrointestinal tract and produces a protracted watery diarrhea. In cattle, this parasite can lead to abortions and substantial herd loss due to culling of infected animals, whereas in cats prolonged courses of diarrhea can lead to abandonment or euthanasia.At the inception of this dissertation work, no genomic data was available for T. foetus. The parasitology community has debated the taxonomic relationship between bovine and feline-associated strains of T. foetus and other Trichomonad parasites. Some have hypothesized that different pathotypes of T. foetus constitute wholly separate species based on a limited number of cross-infectivity studies, a scant amount of genomic DNA and protein sequences, and non-targeted nuclease-based strategies. Still, the community has been slow to adopt this idea.We aimed to use next-generation sequencing (NGS) technology to: sequence the genomes of bovine and feline isolates, utilize the genomes to determine the taxonomic relationship between bovine and feline-associated T. foetus, and determine whether there were detectable genomic differences that might lead to host-specific targets. We hypothesized that significant genomic changes would be detectable and would lead to host-specific targets for future therapeutics.We successfully extracted genomic DNA and produced de novo draft genome assemblies for two Tritrichomonas foetus isolates: strain Beltsville and strain Auburn. Our resulting genomic analyses reveal that these are two members of the same species at the molecular level. These results ran contrary to our initial hypothesis, showing that the difference between these two pathotypes may be subtler than previously believed. We used numerous house-keeping, gold standard phylogenetic markers in addition to bioinformatic and phylogenetic analyses to highlight the profound similarity between these two samples. This work should lay the foundation for a multitude of future investigations into Tritrichomonas foetus in the hopes of producing better therapeutic strategies and clinical outcomes for bovine and feline populations alike.

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