NIH grant: Host associations and phylogenetics of virulent Toxoplasma gondii (1R15AI194254-01A1)

retained text

NIH grant 1R15AI194254-01A1: Host associations and phylogenetics of virulent Toxoplasma gondii
Institute: {'code': 'AI', 'abbreviation': 'NIAID', 'name': 'National Institute of Allergy and Infectious Diseases', 'admin_org_id': '12500003', 'admin_funding_url': ''}. PI: Kelly Anne Speer. Award: $586952.
Start: 2026-07-16T00:00:00.
Project Summary/Abstract
 Toxoplasma gondii is a highly successful intracellular protozoan parasite that has chronically infected
30% of the human population and can cause life-threatening disease in immunocompromised individuals and
fetuses. Outbreaks of fatal toxoplasmosis in healthy humans have been reported in South America, which is also
a hotspot of biodiversity for this parasite and its reservoir hosts (i.e., Felidae). Previous research has focused on
lineages isolated from Europe and North America, which are clonal and do not exhibit hypervirulence in the
human population. In South America, the abundant non-clonal lineages exhibit substantial genetic diversity and
differ widely in virulence, transmissibility, and other biological characteristics. However, the reservoir host
associations, geographic distribution, and evolutionary history of these variable genotypes remain poorly studied.
Our goal is to describe felid host-parasite dynamics and parasite evolution so that we may better understand the
evolution of genetic variation that leads to hypervirulence in Toxoplasma.
 Understanding these fundamental host-parasite dynamics will enable the development of effective
strategies to prevent and manage future outbreaks of severe toxoplasmosis. This project builds on previous work
that the Speer Lab has conducted on disease transmission and host-parasite coevolution in neotropical
mammals, that the Wang Lab has conducted on molecular parasitology of Toxoplasma, that the Walker Lab has
conducted on optimizing molecular genetics from wildlife fecal samples, and that the Sahl lab has conducted on
bioinformatics and phylogenetics of parasites and pathogens. We will provide undergraduate students with
uniquely broad experiences in field work, molecular genetic lab work, tissue culture, and bioinformatics analyses.
The breadth of the expertise that is synergized in this project is one of its innovations.
 Our aims are to:
1) Conduct genomic surveillance of non-clonal Toxoplasma strains in Brazil. Collect felid scat samples for
genomic sequencing and for isolating oocysts that can be used for assays of virulence.
2) Mine sequence data for global occurrence of non-clonal Toxoplasma. Leverage existing genomic data
for reservoir hosts to assemble previously undetected parasites genomes and annotate gene functions.
3) Identify host-specificity and estimate evolutionary history of newly detected Toxoplasma genotypes.
Apply phylogenetic analyses to detect recombination and potential cross-species parasite transmission to
identify reservoir hosts or geographic regions that require surveillance for hypervirulent parasite spillover.

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