Toxoplasma gondii diversity: From seroprevalence in multiple host species to genotypic analysis of field isolates

Toxoplasma gondii is an important human and veterinary pathogen. T. gondii is found in all corners of the world in virtually all species of mammals and birds, yet its prevalence and clinical importance varies by geographic location and host species. In addition, it is increasingly clear that parasite genetic diversity plays a role in pathogenesis. In parallel with this recognition, new technologies make it possible to study the genetic diversity of this parasite at any level of resolution. This thesis seeks to exploit screening and genome-scale technologies to determine the genetic diversity of these parasites worldwide, highlighting features that may be associated with pathogenesis and test theories about the role of genotype in clinical disease outcomes. After a brief introduction to T. gondii, including life cycle, global distribution, host interactions, pathogenesis and genetic diversity (Chapter I), Chapter II examines the distribution of T. gondii among diverse host species in a single geographic region. New genome-scale technologies for genotyping known and unknown parasites strains are discussed in Chapters III and IV; Chapter III discusses the genetic analysis of the progeny of laboratory crosses while Chapter IV describes the technical aspects of exotic strain genome analysis. Chapter IV also includes an analysis of these isolated strains. In Chapter V, the data from this thesis is summarized and future directions discussed.