How elephant host proteins fight-or fail-against EEHV: Insights from a multi-contrast proteomic enrichment study

Elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD) is a rapidly fatal syndrome of juvenile Asian elephants, but the host-response programs distinguishing progression from survival and the underlying pathophysiology remain poorly defined. The serum proteome of 62 Asian elephants (Elephas maximus) was profiled using a multi-contrast design stratified by age, clinical status, and infection history; protein abundance was analyzed by empirical Bayes linear modeling and Gene Ontology enrichment with semantic similarity reduction. Clinically affected elephants showed enrichment of inflammatory and stress-associated processes-including cytokine signaling and chromatin remodeling-with suppression of type I interferon signaling and homeostatic functions, whereas asymptomatic exposed elephants showed enrichment of metabolic pathways, including fatty acid and pyruvate metabolism, vesicle-mediated transport, and protein quality control. Disease-versus-exposure comparisons distinguished a progression program (inflammatory escalation with loss of proteostasis and cell adhesion) from a resilience program (preserved metabolic and cellular homeostasis); juvenile susceptibility was further associated with impaired lipid and calcium regulation and disrupted intracellular transport. Collectively, these patterns support a pathology-centered model in which fatal EEHV-HD reflects endothelial injury coupled with maladaptive inflammation and metabolic failure. Protein-level interpretation identified candidate drivers of inflammatory amplification, endothelial barrier disruption, coagulation imbalance, and resilience-including JAK1, IL1RL2, IFI44, KCNJ15, MSN, HECW2, ITPR3, MFN2, AKT1, BMPER, and DROSHA-providing a mechanistic bridge between serum proteomic changes and the vascular lesions, thrombocytopenia, DIC-like coagulopathy, edema, and hemorrhage of EEHV-HD. These findings nominate candidate proteomic signatures for future diagnostic and risk-stratification studies; longitudinal individual-level validation is required before clinical application. Because diagnostic screening identified all PCR-positive sick cases as EEHV1A and pooled group-level serum profiles were analyzed, these signatures should be interpreted as exploratory host-response programs specifically reflecting acute EEHV1A disease requiring individual-level validation.