Molecular Phylogenetics, Diagnostics and Control of Apicomplexan Parasites

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The long term goal of my research program is to explore and understand the interactions between parasites of the phylum Apicomplexa and their hosts at the historical, organismal (host-parasite) and molecular levels. These parasites cause important animal and human diseases such as malaria, toxoplasmosis, cryptosporidiosis and coccidiosis. I propose to further our understanding of these relationships by pursuing three main areas of study: 1) Investigate apicomplexan phylogeny and host-parasite coevolution using multi genome molecular markers with morphological and morphometric characters: We will determine the biodiversity of apicomplexan parasites in humans, domesticated animals and wildlife (potential zoonotics) by generating sequence data (nuclear 18S rDNA, plastid rDNA/polymerase B, and mt cytochrome c oxidase subunit I, COI) from apicomplexan parasites that infect both domestic and, largely ignored, wildlife hosts. Our newly developed PCR primer pairs will generate species-specific COI-based DNA barcodes that will be used to identify specifically coccidia (Eimeriorina) including enteric (e.g. Eimeria) and tissue (e.g. Toxoplasma) coccidia. We will modify our DNA barcode primers for use in a multiplexed NGS assay to both identify and enumerate mixed coccidia in biological samples such as fecal or tissue samples; this method will permit rapid protistan parasite biodiversity and species discovery; 2) Generate complete mitochondrial (mt) genomes from biologically diverse apicomplexan parasites to explore the structural evolution of mt genomes and generate sequence data necessary for inferring the evolutionary history of these cosmopolitan parasites. 3) Explore immunological control of coccidia of domestic poultry. We will determine the natural prevalence of Eimeria that infect domestic turkeys nationally and internationally to determine the number of species required in a multivalent live coccidiosis vaccine against turkey coccidiosis. We will refine and further develop a recombinant multivalent vaccine technology that combines two parasite antigenic epitopes with a host-derived immune modulating epitope (HMGB1). The current Bacillus subtilis expression vector for this multivalent vaccine construct will be converted into a strictly peptide based (i.e. chemically synthesized) form and tested for biological activity in vivo when delivered by various means. Successful vaccination against Eimeria species using a non-viable vaccine construct (a global first) would address vaccine production, transportation and shelf life issues as well as avoid health implications of using live coccidiosis vaccines in commercial poultry.