Lauren L. Howard1, DVM, DACZM; Sharon L. Deem2, DVM, PhD, DACZM; Ramiro Isaza3, DVM, DACZM, MPH
Elephant endotheliotropic herpesvirus (EEHV) causes acute and often fatal hemorrhagic disease in young Asian elephants (Elephas maximus), and is the single largest cause of death for Asian elephants born in North America since 1978.1 The North American Asian elephant population is declining and is not sustainable. A recent population modeling study demonstrated that elimination of EEHV-related mortality, along with increasing breeding rates, gives this population its best chance of reaching a sustainable level.2 There have been 21 EEHV-associated deaths in North American Asian elephants born in captivity since 1978. An additional 9 Asian elephants have become ill from EEHV infection but have survived with supportive care and antiviral treatment. The majority of EEHV-associated deaths occurred in elephants between 1 and 6 yr of age. A recently completed case controlled epidemiologic investigation of selected North American institutions found no evidence to support an association between EEHV occurrence in Asian elephants and exposure to African elephants. Additionally, there was no evidence in Asian elephants to support an association between other husbandry or individual risk factors with EEHV occurrence. Standardized classifications of EEHV-associated illness and fatalities are needed to facilitate the development of a universally accepted roster of EEHV cases.3
1. Richman, L.K., and G.S. Hayward. 2012. Elephant herpesvirus. In: Miller, R.E. and M.E. Fowler (eds.). Fowler’s Zoo and Wild Animal Medicine: Current Therapy 7. Saunders Elsevier, Saint Louis, Missouri. Pp. 496–502.
2. Gazlay, T., and L. Faust. 2012. North American Asian Elephant (Elephas maximus) SSP: a demographic population viability investigation of the effects of EEHV. Unpublished data. Pp.7.
3. Ninth Annual EEHV International Workshop Proceedings. Houston, Texas. Pp. 36.