Russell's viper envenomation in a 9-month pregnant mare saved with high-dose antivenom: a first-in-world case report

Snakebite during pregnancy is an uncommon but potentially catastrophic event, with maternal and foetal outcomes closely related to the severity of envenomation. While snakebite in pregnant women has been sporadically reported and is known to be associated with significant obstetrical complications, envenomation in animals, particularly in pregnant horses, is exceedingly rare. Only a few isolated cases of snakebite in horses have been documented, and to the best of our knowledge, snakebite in a pregnant mare has not been previously reported in the medical or veterinary literature. Russell's viper (Daboia russelii) envenomation is a major cause of morbidity and mortality in South Asia. We describe the first documented case of severe Russell's viper envenomation in a 5.5-year-old Marwari mare at 9 months of gestation following confirmed double bites to the muzzle. The mare developed rapidly progressive craniofacial oedema, respiratory compromise and severe venom-induced consumption coagulopathy with recurrent rebound coagulopathy. Management required intensive monitoring and administration of an unusually high cumulative dose of equine polyvalent antivenom totalling 60 vials. Despite the high venom burden, pregnancy-associated bleeding risk and delayed venom redistribution from facial tissues, the mare achieved complete clinical recovery with preservation of foetal viability. This case highlights the unique challenges of snakebite management in pregnant large animals, including venom depot effects, recurrent coagulopathy and foetal risk. Aggressive antivenom therapy guided by coagulation monitoring can result in favourable maternal and foetal outcomes. This report represents the first documented case of Russell's viper envenomation in a pregnant horse.