Submitted to: International Meeting on Molecular Epidemiology and Evolutionary Genetics in Infectious Disease
Publication Type: Abstract Only
Publication Acceptance Date: June 29, 2004
Publication Date: July 8, 2004
Citation: Rosenthal, B.M. 2004. Might Toxoplasma gondii have an ecological analogue in the sister genus Besnoitia?. Abstract. International Meeting on Molecular Epidemiology and Evolutionary Genetics in Infectious Disease. Paper No. 382. Interpretive Summary: The lack of genetic diversity among livestock parasites belonging to the genus Besnoitia is discussed in comparison to analagous studies of Toxoplasma gondii. Like T. gondii, comprised of recently adapted clonal parasite strains, this comparative analysis suggests that other coccidian species may have originated subsequent to livestock domestication
Technical Abstract: Toxoplasma gondii commands scientific interest and public health concern because of the burden it places on human health. Although this taxon represents but one of (at least) hundreds of related tissue cyst-forming coccidian Apicomplexans, we remain largely ignorant of this evolutionary context. In order to develop a clearer understanding of the group's history and epidemiology, we are exploring the extent of genetic variation and the manner in which such genetic diversity is partitioned in such related parasite taxa, using the tools of molecular systematics and comparative population genetics. Here, I explore problems in discerning relevant and useful definitions for parasite species and genera, focussing on new data derived from analyses of isolates presumpatively assigned to species of Hammondia and Besnoitia. In particular, new evidence indicates that a broadly distributed and genetically homogeneous parasite lineage in the genus Besnoitia may have evolved to exploit domesticated bovid, caprine, and equiid hosts in a manner analagous to that of T. gondii, which exploits an exceptionally broad intermediate host range but which appears to have adapted to new transmission opportunities subsequent to the advent of human agriculture.