Use of Thromboelastography in the Clinical Management of EEHV1 Infection in a Young Female Asian Elephant (Elephas maximus)
Elephant endotheliotropic herpesviruses (EEHVs) are betaherpesviruses that can cause fatal hemorrhagic disease in both Asian (Elephas maximus) and African (Loxodonta africana) elephants.2 In early 2017, a 4.5-year-old female Asian elephant was diagnosed with EEHV1a on routine blood PCR testing. Within one week, whole blood viral levels increased from 11,000 vge/ml to 500,000 vge/ml. Clotting time and strength had been monitored using thromboelastography (Thrombelastograph Hemostasis Analyzer model 5000, Haemonetics Corporation, Braintree, MA 02184 USA) starting before disease occurrence, with changes in both parameters paralleling clinical progression and resolution of the disease.1 One day following detection of maximum viral titres, clot initiation time (mean 2.86±0.99 minutes prior to viremia) increased to 49.3 minutes and clot strength (maximum amplitude; mean 84.8±2.56 mm prior to viremia) decreased to 58.2 mm. These values returned to baseline during treatment and have remained stable since recovery. During the course of the disease, the elephant was treated with oral and rectal famcyclovir, intravenous and rectal fluids, intravenous plasma transfusions harvested from on-site conspecifics, intravenous and rectal antibiotics, parenteral NSAIDs, and intravenous lyophilized platelet suspensions. The elephant appeared clinically normal 15 days after initial diagnosis, and famcyclovir treatment was continued until viral levels dropped below 1,000 vge/ml, 22 days from initial diagnosis. Following resolution, the elephant has been monitored with weekly EEHV viral levels, thromboelastography, haematocrit, and total protein measurements. EEHV1 titres greater than 1,000 vge/ml have not been detected since recovery.
The authors would like to thank Erin Latimer, Dr. Bill Lindsay, Gary Jacobson, Janice Aria, and all the trainers at the Ringling Brothers and Barnum & Bailey Center for Elephant Conservation for their assistance in the care and recovery of this case.
1. Perrin KL, Krogh AK, Kjelgaard-Hansen M, Howard L, Bochsen L, Kiso WK, et al. Thromboelastography in the healthy Asian elephant (Elephas maximus): Reference intervals and effects of storage. J Zoo Wildl Med. 2018;49:54–63.
2. Stanton JJ, Zong J-C, Eng C, Howard L, Flanagan J, Stevens M, et al. Kinetics of viral loads and genotypic analysis of elephant endotheliotropic herpesvirus-1 infection in captive Asian elephants (Elephas maximus). J Zoo Wildl Med. 2013;44:42–54.