Egyptian Rousette Bat (Rousettus aegyptiacus) Interleukin-13 (IL-13) is a Th2-associated cytokine involved in regulation of allergic inflammation, mucosal immunity, and tissue remodeling, and is likely produced by activated CD4⁺ T helper cells and other type 2 immune cells. IL-13 signals through receptor complexes containing IL-13Rα1 and IL-4Rα, activating JAK/STAT6 pathways that regulate gene expression associated with alternative macrophage activation, mucus production, and modulation of inflammatory responses. In R. aegyptiacus, a natural reservoir host for filoviruses such as Marburg virus, IL-13 is of particular interest for understanding how Th2-type responses contribute to immune balance and tissue repair while limiting excessive pro-inflammatory damage. Regulation of IL-13 signaling may influence the balance between antiviral Th1 responses and anti-inflammatory or tissue-protective pathways, potentially contributing to the species’ ability to tolerate viral infections with minimal clinical disease. Characterization of Egyptian Rousette Bat IL-13 supports research into bat-specific immune polarization, host–pathogen interactions, and mechanisms of immune tolerance. Studying IL-13 dynamics in this reservoir species enhances comparative immunology research and provides insight into conserved and divergent Th2 regulatory pathways relevant to allergy, fibrosis, and chronic inflammatory disease in humans.