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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #383428

Research Project: Detection and Control of Foodborne Parasites for Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Structure of the Toxoplasma gondii sporocyst wall exposed to household bleach

item DUMETRE, AURELIEN - Aix-Marseille University
item Dubey, Jitender
item FERGUSON, DAVID - Oxford University

Submitted to: Parasite
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2021
Publication Date: 10/7/2021
Citation: Dumetre, A., Dubey, J.P., Ferguson, D.J. 2021. Structure of the Toxoplasma gondii sporocyst wall exposed to household bleach. Parasite. 28(68).

Interpretive Summary: Food safety due to microbial contamination of foods remains a public health concern worldwide. Among the parasitic contaminants, fecal contamination of foods due to protozoans such as Cyclospora, Cryptosporidium, and Toxoplasma are of prime concern. Knowledge of oocyst biology of T. gondii or Cyclospora is limited, because of the limited availability of oocysts for experimentation. Coccidian oocysts are resistant to disinfectants, such as Clorox. Here, the authors describe the chemical basis of resistance of the oocysts. These results will be of interest to parasitologists, and public health workers. This research was completed before the closure of Toxoplasma research at ARS in 2018.

Technical Abstract: Toxoplasma gondii oocysts are responsible for food- and water-borne infections in humans worldwide. They are resistant to common chemical disinfectants, including chlorinated products, presumably due to the structure and molecular nature of the oocyst wall but also the sporocyst wall. In this study, we used fluorescence microscopy and transmission electron microscopy to characterize the structure of both the oocyst and sporocyst walls, exposed to household bleach. Bleach dissolved the outer layer of the oocyst wall but also the outer layer of the sporocyst wall of those sporocysts exposed due to rupture of the oocyst wall. The loss of the outer sporocyst wall layer was linked to the degradation of dityrosine cross-links and glycoproteins. This study suggests that the inner layers of the oocyst and sporocyst walls are the main structures responsible for the resistance of the parasite to household bleach.