Molecular Epidemiological Investigation of Viruses in Captive and Wild Amur Tigers in Northeast China

A systematic molecular epidemiology survey was conducted on ten viruses in 226 captive and two wild Amur tigers from Northeast China. The target viruses were: feline panleukopenia virus (FPV), feline herpesvirus-1 (FHV‑1), feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), canine distemper virus (CDV), feline coronavirus (FCoV), feline calicicivirus (FCV), influenza A virus (IAV), hepatitis E virus (HEV), and rotavirus A (RVA). The overall infection prevalence was 45.6% (103/226). FPV (25.2%) and FHV‑1 (20.4%) were the dominant pathogens, followed by CDV (1.8%), FIV (1.8%), FCoV (0.9%), and FeLV (0.4%); no samples tested positive for FCV, IAV, HEV, or RVA. Co‑infections were observed in 13.6% of positive individuals. Key findings include: (1) the first detection of FeLV in this subspecies; (2) age-dependent prevalence (juveniles, 56.5%; seniors, 25.0%; adults, 14.6%); (3) regional prevalence disparities (Harbin: 52.6%, Shenyang: 55.8%, Hailin: 29.9%); (4) Phylogenetic analysis revealed that FPV sequences from captive tigers formed a distinct monophyletic clade, whereas the sequence from the wild tiger clustered within the CPV-2a lineage. In addition, FIV strains clustered with domestic cat lineages. Despite existing vaccination protocols, the persistent high prevalence of FPV and FHV‑1 indicates suboptimal vaccine effectiveness. Therefore, this study, which clarifies the prevalence of ten viruses in Amur tigers and provides foundational data for epidemiological surveillance, underscores the necessity of age-stratified immunization, enhanced raw meat safety, and transboundary surveillance.