First fatal elephant endotheliotropic herpesvirus type 5 infection in a captive Asian elephant in Germany

Abstract Background: Elephant endotheliotropic herpesvirus (EEHV) infection is the most common cause for lethal hemorrhagic disease in captive juvenile Asian elephants (Elephas maximus). Although EEHV-1 is known as the most likely cause of fatal haemorrhagic disease in Asian elephants, EEHV-5 was lately involved in lethal cases of haemorrhagic disease in captive elephants. Case presentation: Here we report the first death of a four-year old Asian elephant diagnosed with EEHV-5 in Germany. Molecular diagnosis yielded detection of EEHV-5 DNA in all tested tissues. Histopathological examination revealed typical features of hemorrhagic disease in all examined organs. EEHV-5 was sequenced from total DNA isolated from heart tissue by Illumina and Nanopore sequencing. Sequencing data showed 3881 variants, distributed across the entire genome, compared to the published EEHV-5 sequence. Conclusions: We have detected EEHV-5 in a fatal disease case of a male Asian elephant. Whole genome sequencing revealed substantial differences of our DNA isolate compared to available EEHV-5 sequences. This report of fatal haemorrhagic disease associated with EEHV-5 infection should raise awareness for EEHV-5 as important elephant pathogen. Genome sequencing and downstream SNPs analysis will further encourage future research to understand genetic diversity, pathogenesis and virulence of EEHVs with respect to developing new diagnostic methods, prophylactic strategies, and implementation of surveillance and control measures.