Elapid snake envenomation in horses: 52 cases (2006-2016).
Authors: Bamford N J, Sprinkle S B, Cudmore L A, Cullimore A M, van Eps A W, Verdegaal E J M M, Tennent-Brown B S
Journal: Equine veterinary journal
Summary
# Elapid Snake Envenomation in Horses: Clinical Presentation and Treatment Outcomes Elapid snake bites in horses present a diagnostic challenge in endemic areas, particularly across Australia, where clinical recognition and appropriate antivenom therapy can be lifesaving. This retrospective analysis of 52 confirmed cases (2006–2016) characterised the syndrome as predominantly neurotoxic, with 94% of affected horses displaying generalised neuromuscular weakness alongside staggering gait, muscle fasciculations, recumbency, mydriasis, ptosis and tongue paresis; concurrent rhabdomyolysis (50%) and haemolysis (19%) commonly complicated the clinical picture. Diagnostic confirmation proved challenging—only 17% of urine samples tested positive on snake venom detection kits—making clinical suspicion and response to antivenom therapy the most reliable confirmatory indicators, though 43% of surviving horses required multiple vials. Despite the severity of neurotoxic signs, 86% of the 49 horses receiving antivenom survived, highlighting the critical importance of recognising this presentation and initiating treatment promptly. Equine practitioners in snake-endemic regions should maintain heightened suspicion for elapid envenomation during spring and summer months when any horse presents with unexplained generalised neuromuscular weakness, altered mentation or concurrent muscle breakdown, particularly when traditional diagnostic approaches yield no clear diagnosis.
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Practical Takeaways
- •In endemic areas during spring/summer, consider elapid envenomation in horses presenting with unexplained neuromuscular weakness, altered mentation, rhabdomyolysis or haemolysis—even without a witnessed bite
- •Prompt antivenom administration is critical for survival; diagnostic confirmation by clinical response to treatment is more reliable than venom detection kits (only 17% sensitivity)
- •Plan for potential need for multiple antivenom vials (43% of survivors required >1 vial) and intensive supportive care for neuromuscular symptoms including recumbency risk
Key Findings
- •94% of elapid snake envenomation cases presented with neurotoxicity characterised by generalised neuromuscular weakness
- •Concurrent rhabdomyolysis occurred in 50% of cases and haemolysis in 19% of cases
- •Overall survival was 86% among 49 horses receiving antivenom, with 43% of survivors requiring multiple vials
- •Snake venom detection kit testing was positive in only 17% (3/18) of urine samples evaluated