Date of Award


Document Type


Degree Name

Master of Science (MS)


Microbiology and Molecular Genetics

First Advisor

Bruno Martorelli Di Genova

Second Advisor

John Salogiannis


Toxoplasma gondii is a widespread human pathogen, and it is estimated to infect one-third of the global population. T. gondii infects nearly all warm-blooded animals, including humans, allowing for broad dissemination across many host species. Prevalence of this parasite is observed worldwide; however, warmer climates are apt to increase seropositivity among their populations. Toxoplasmosis is acquired by ingesting contaminated food and water with parasite-containing oocysts from cat feces. It may also be acquired from consuming undercooked meat infected with tissue cysts. T. gondii infection poses a significant risk for low-income, underprivileged populations without access to proper healthcare resources, clean food and water sources, and adequate living conditions.We aim to understand the incidence of environmentally acquired toxoplasmosis better. To accomplish this, we analyzed samples collected from various geographical sites in the underserved community of Pau da Lima, Brazil. Aliquots of soil and sewer water were analyzed using standard quantitative polymerase chain reaction (qPCR) for Toxoplasma gondii targeting the gene standard B1. Using western blotting, human serology was assessed for a previously characterized sporozoite-specific protein, Toxoplasma-gondii embryogenesis-related protein (TgERP). TgERP differentiates between tissue cyst and oocyst infections due to its specific presence in the oocyst stage of Toxoplasma gondii development. Finally, rat brains were analyzed using a validated isolation protocol with dextran centrifugation and immunofluorescent imaging. Our analysis produced predominantly negative results from the environmental samples: soil, sewer water, and rat brains. Nevertheless, the human cohort sampled from Pau da Lima, Brazil produced seropositive results for oocyst infection utilizing TgERP. This highlights the difficulty of isolating Toxoplasma gondii from the environment. Also T. gondii oocysts are highly resilient and have a very low infection dose. There is currently no standard in the field for environmental analysis despite a clear indication that oocyst-contaminated resources and feline exposure are infecting populations. We hope the insights and novel protocols developed in this research can be further expanded in the field. Our data provides insight into the more significant public health issues and solutions that can be implemented in low-income, vulnerable patient populations.



Number of Pages

115 p.

Available for download on Sunday, April 26, 2026

Included in

Microbiology Commons