Current surveillance practices for shedding of elephant endotheliotropic herpesviruses in breeding and bachelor Asian elephant Elephas maximus herds in Europe

Abstract

Elephant endotheliotropic herpesvirus-haemorrhagic disease (EEHV-HD) is the most common cause of death in juvenile captive Asian elephants Elephas maximus. Currently, weekly whole blood screening is recommended for the detection of viraemia, which occurs prior to the development of clinical disease, but there are no recommendations for monitoring viral shedding into the environment. The aims of this study were to evaluate current EEHV shedding surveillance protocols in Asian elephant herds in Europe, as well as to collate and describe existing EEHV shedding data from these herds. Results from a European Association of Zoos and Aquaria Taxon Advisory Group-approved survey revealed that as of January 2021, 42% of breeding institutions had a protocol for screening for EEHV viraemia, while 30% monitored viral shedding. Shedding data were available from 12 institutions, where a total of 2,863 samples had been collected for polymerase chain reaction (PCR) analysis. Overall, 13.9% of all tested samples were positive for EEHV and 48.9% of elephants tested positive for EEHV. EEHV-1 was both the most common genotype detected and the most commonly tested for. Evidence of the presence of EEHV was reported in 12/12 (100%) of breeding herds. Routine monitoring of EEHV shedding is recommended to enable better understanding of the dynamics of EEHV infection and disease.