HPD and viral infectious disease: By analyzing 150 differentially expressed genes across various pathways, we constructed a protein–protein interaction network and identified several key genes: APOC3 from the PPAR signaling pathway [84], HGD, HMGCS2, HPD, and FAH from the steroid biosynthesis pathway, and ALDOB from the glycolysis pathway, with higher topology scores ranging from 0.701 to 0.999 These scores indicate their critical roles in metabolic pathways during viral infections.