Ecological and biomedical functions of parasitofauna: Mechanistic and evolutionary perspectives

Parasites have traditionally been viewed primarily as pathogenic organisms associated with disease and economic burden. However, growing evidence indicates that parasitofauna-the diverse assemblage of parasitic organisms across ecosystems-plays fundamental roles in ecological regulation, host evolution, and biomedical innovation. Despite increasing recognition of these functions, existing literature largely treats ecological, immunological, and translational aspects of parasitism in isolation, lacking an integrated mechanistic framework that links these domains across biological scales. This review synthesizes current knowledge to provide a cross-disciplinary perspective on the ecological and biomedical functions of parasitofauna. Ecologically, parasites act as regulators of host population dynamics, modulators of biodiversity, and contributors to nutrient cycling and ecosystem stability. Evolutionarily, they impose strong selective pressures that shape host genetic diversity, immune system architecture, and behavioral adaptations through mechanisms such as allele frequency shifts and fitness trade-offs. From a biomedical standpoint, parasite-derived molecules demonstrate promising immunomodulatory, anti-inflammatory, and anticancer properties, with evidence derived primarily from in vitro studies and preclinical animal models, and limited support from early-phase clinical trials. In addition, interactions between parasites and the gut microbiome highlight their role in immune regulation and potential implications for inflammatory and metabolic disorders. By integrating ecological theory, evolutionary biology, and translational research, this review proposes a unified conceptual model of parasitofauna as multi-level regulators rather than solely pathogenic agents. This perspective supports a shift toward evidence-based parasite management strategies that balance disease control with ecological and therapeutic considerations. The synthesis also identifies key knowledge gaps and emphasizes the need for mechanistic, multi-system studies to better understand context-dependent outcomes of host-parasite interactions.