Early EEHV-1B Detection and Successful Treatment of EEHV-HD in an Asian Elephant Calf (Elephas maximus)
Abstract
In November 2017, a three-year-old Asian elephant (Elephas maximus) at Woburn Safari Park, UK, tested positive for EEHV-1B DNAemia on a routine weekly blood sample without clinical signs. Hematological changes included a marked leucopenia, with lymphopenia and marked monocytopenia, and thrombocytopenia. Persistently high EEHV DNAemia and further reduction in white blood cells and platelets were noted on Day 3. Despite the lack of clinical signs, treatment under standing sedation was initiated, consisting of twice-daily intravenous ganciclovira (5 mg/kg), fluids (0.9% NaCl, 2 ml/kg), and elephant plasma (300–500 ml per session), and rectal fluid therapy (warm tap water via hosepipe, 10–20 ml/kg). Viral loads decreased within 48 hours of treatment and hematological parameters improved gradually from Day 6. On Day 9, the calf developed mild clinical signs including petechiae on the tongue and vulva, followed by mild submandibular and limb oedema. Dexamethasoneb (0.05 mg/kg IM) was administered for two days following initial clinical presentation, leading to a gradual improvement in clinical signs, with consecutive marked increase of circulating monocytes and reduction of lymphocytes. Clinical signs resolved by Day 12 and IV antivirals ceased on Day 15. Rectal acyclovirc (15 mg/kg q 12h) and fluids continued until Day 17. EEHV PCR was negative from Day 23. Weekly blood screening and in-house hematology continued, showing two subsequent subclinical episodes that did not require treatment three and five weeks later.
This case highlights the value of easily accessible, in-house hematologic analysis in the decision making of clinical and subclinical cases, discusses the potential role of the immune system in the development of clinical signs and the efficacy of corticosteroids in aiding treatment.
Endnotes
a. Cymeven® 500 mg, Roche Products Ltd, Welwyn Garden City, AL7 1TW, UK
b. Dexadreson® 2 mg/ml, MSD Animal Health, Milton Keynes, MK7 7AJ, UK
c. Acyclovir 800 mg tablets, Ranbaxy Ltd, London, W4 5YE, UK
Acknowledgments
The authors would like to thank the Woburn Safari Park elephant care team under Darren Fellowes, and colleagues at the Scott Veterinary Clinic, Bedford, for their hard work and commitment shown during the treatment of Tarli, with particular mention of Emily Relph VCA who performed all on-the-day in-house hematology and the virology team at APHA Weybridge who ran the EEHV PCR.