Compostagem como alternativa sustentável para o descarte de cadáveres de felinos com esporotricose: avaliação da inativação de sporothrix brasiliensis e condições térmicas do processo

Abstract

Sporotrichosis, caused by S. brasiliensis, represents a significant public health challenge, particularly in Brazil, where high rates of feline mortality and human infection are recorded. Proper disposal of the carcasses of infected cats is essential to prevent pathogen dissemination and minimize environmental impact. In this context, the present study investigated composting as a sustainable alternative to incineration for the elimination of S. brasiliensis. The study was conducted in two phases. First, the viability of the fungus under different thermal conditions and the challenges encountered in the process were evaluated. Initially, the presence of the fungus in the carcasses was confirmed through imprinting and fungal culture. Subsequently, three composting experiments were conducted with continuous temperature monitoring. The composting units, built using construction waste materials, reached temperatures above 50°C, a potential indicator of pathogen inactivation. However, throughout the process, it was not possible to re-isolate the fungus at any time, highlighting methodological challenges in verifying its complete elimination, even though the analysis of the biocompost indicated potential for application in acidic soils, expanding the perspectives for utilizing the resulting material. To assess fungal viability under thermal stress, a second phase of the study was conducted, in which yeast colonies were subjected in vitro to different temperatures (≤ 0°C, 22°C, 37°C, 43°C, 56°C, 63°C, and 67°C). Exposure to temperatures up to 63°C for five hours still resulted in relative viability, with non-survival confirmed only after reaching 67°C for five hours. This suggests that the lethal temperature for S. brasiliensis is between 63°C and 67°C, and may also be influenced by the duration of exposure. Thus, this study contributes to the development of sustainable strategies for managing contaminated biological waste, highlighting composting as a promising alternative for the safe elimination of S. brasiliensis. However, improvements in experimental protocols and further investigations are necessary, reinforcing the importance of continuing this approach in future studies, as the implementation of evidence-based guidelines could optimize procedural safety and mitigate environmental and public health risks.