Mycotoxins as silent modulators of enteric viral susceptibility and vaccine responsiveness

Enteric viral infections remain a major cause of morbidity and mortality worldwide, particularly in children and intensively raised livestock. Although live oral vaccines have reduced disease burden, vaccine efficacy varies greatly across regions. Factors such as host genetics, microbiota, maternal antibodies, and nutrition have been widely studied, whereas chronic exposure to dietary toxicants has received less attention. Mycotoxins, fungal metabolites contaminating staple crops including maize, wheat, and peanuts, are commonly consumed at low but persistent levels in regions heavily affected by enteric viral diseases. Increasing evidence shows that mycotoxins disrupt intestinal barrier integrity, alter innate and adaptive immune responses, and reshape gut microbial ecology even without overt toxicity. These effects target pathways essential for antiviral defense and oral vaccine efficacy. This review proposes a mechanistic framework in which chronic mycotoxin exposure alters epithelial-immune-microbiota interactions, thereby increasing susceptibility to enteric viral infection and reducing vaccine-induced protection. We summarize evidence linking mycotoxins to barrier dysfunction, interferon dysregulation, antigen-presenting cell impairment, IgA suppression, intestinal stem cell injury, and microbiota-mediated changes in viral infectivity. Recognizing mycotoxins as covert regulators of mucosal antiviral immunity may provide new strategies to improve oral vaccine performance and reduce global enteric viral disease burden.