Implementation of a prototype for the in vitro production of Giardia lamblia cysts.

Abstract

Background: Giardia lamblia is a flagellated protozoan responsible for giardiasis, an intestinal infection with a significant impact on public health. The cyst form is a resistant and infectious structure of the parasite, responsible for its transmission [1]. The controlled and large-scale production of cysts in the laboratory allows for the evaluation of efficacy and the development of new formulations of cleaning products, contributing to the improvement of giardiasis control strategies. Objective: This work aimed to develop and validate a laboratory prototype that allows the in vitro production of Giardia lamblia cysts, ensuring guidelines, purity, and safety for applications in research or diagnosis. Methods: Trophozoites were cultured in vitro in TYI-S-33 medium and subsequently subjected to different encystment conditions through modification of the medium composition. Different concentrations of bovine bile were analyzed, as well as the influence of fetal bovine serum, glucose (the main energy source), and lactic acid on the encystment process. Results: Cyst formation was observed in all tested conditions, demonstrating the ability to induce encystment in the different media evaluated. The prediction of cyst production will be verified through staining with propidium iodide and fluorescein diacetate, allowing the evaluation of cell membrane integrity and metabolic activity, relating productivity to prediction. Conclusions: These specific results are an important step towards establishing an optimized methodology for the production of Giardia cysts, with potential application in disinfectant efficacy assays, testing hygiene protocols in shared environments, supporting the development of new disinfectant formulations, and contributing to the improvement of giardiasis control strategies.