Updates on Elephant Endotheliotropic Herpesvirus (EEHV) EEHV-5 Infections in Asian Elephants (Elephas maximus)
Lauren L. Howard1, DVM, DACZM; Lisa Atkins2, BS; Joseph P. Flanagan1, DVM; Erin Latimer3, BS; Dennis Schmitt4, DVM, PhD, DACT; Arun Zachariah5, BVSc, AH, MSc; Gary S. Hayward6, PhD; Jeffrey J. Stanton2, DVM; Paul D. Ling2, PhD
1Houston Zoo Inc., Cambridge, Houston, TX, USA; 2Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA; 3Elephant Herpesvirus Laboratory, Smithsonian National Zoological Park, Washington, DC, USA; 4Darr School of Agriculture, Missouri State University, Springfield, MO, USA and Ringling Bros. Center for Elephant Conservation, Polk City, FL, USA; 5Department of Forests and Wildlife, Kerala State, India; 6Viral Oncology Program, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
Elephant endotheliotropic herpesviruses (EEHVs) can cause acute hemorrhagic disease with high mortality rates in Asian elephants (Elephas maximus). Recently, a new EEHV type known as EEHV-5 has been described, but its prevalence and clinical significance remains unknown. To address this issue, we looked for EEHV-5 in 2 captive herds in North America and in over 50 elephants from India. In the first captive herd, a 42-yr-old wild-born female Asian elephant demonstrated signs of illness (swollen temporal glands, oral hyperemia, and generalized depression) over a three week period during the spring of 2011 that coincided with EEHV-5 viremia as detected via real time PCR on whole blood samples. Retrospective analysis of stored blood samples and trunk washes during the spring of 2011 from the other six elephants in the herd demonstrated shedding of EEHV-5 in trunk secretions in all six elephants and EEHV-5 viremia in five elephants. EEHV-5 trunk shedding and viremia without associated clinical signs was also detected in an elephant that was recently transferred between herds within North America. Finally, EEHV-5 was detected in 20% of trunk washes obtained from over 50 Asian elephants living in India. The results suggest that EEHV-5 infection might be common within captive and range country Asian elephants and in some cases it can cause illness.