Multiple etiological agents associated with the deaths of trafficked pangolins

Pangolins represent the most heavily trafficked mammal globally and harbor diverse microorganisms, raising the concern that illegal trade increases their susceptibility to infectious diseases and facilitates the spread of zoonotic pathogens. In this study, internal organ and fecal samples were collected from 15 confiscated pangolins rescued at the Jinhua Wildlife Rescue Station in Zhejiang Province, China. Metatranscriptomic analysis combined with polymerase chain reaction (PCR) screening detected pestivirus, canine parvovirus 2 (CPV-2), human parainfluenza virus 2 (HPIV2), and Pseudomonas aeruginosa at high abundance in three deceased individuals, while no candidate pathogens were identified in the remaining 12 surviving animals. Two of the deceased pangolins, Pujiang-Pangolin-2 and Pujiang-Pangolin-3, were co-infected with four and two pathogens, respectively, and both exhibited more severe pathological lesions than Qingtian-Pangolin-1, in which only CPV-2 was detected. Pujiang-Pangolin-2 showed markedly elevated levels of CPV-2 and P. aeruginosa in the lung and spleen, accompanied by extensive tissue damage. Pujiang-Pangolin-3 had a higher abundance of pestivirus and presented with pronounced internal hemorrhage. Notably, phylogenetic analyses reveal that the pestivirus, CPV-2, and HPIV2 detected in the infected pangolins were closely related to strains previously identified in Manis javanica, domestic dogs from Vietnam, and humans from the Netherlands, respectively, while the P. aeruginosa sequences clustered with isolates obtained from human clinical samples both within China and internationally.Together with prior reports, these data suggest that trafficked pangolins are highly susceptible to diverse infections and may contribute to the transmission of zoonotic pathogens across species and geographic boundaries.