Grayanotoxin poisoning in animals following the ingestion of Ericaceae plants

Plant poisoning in animals, often associated with wild and ornamental species, is a significant concern in veterinary medicine. Due to clinical signs observed in humans after consuming "mad honey", interest in grayanotoxins, produced by Ericaceae plants, has increased. However, effects on animal health have been scarcely addressed despite their interest for veterinary toxicology. This systematic review, following PRISMA guidelines, identified 31 records of grayanotoxin poisoning in animals following the ingestion of plants, affecting a total of 111 livestock and 11 companion animals. Cases were predominantly reported in livestock, namely sheep and goats, and less frequently in companion animals, including dogs, cats, rabbits, tortoises, and pigs. Studies report an estimated toxic dose of 0.1 % of body weight in fresh foliage for ruminants. Rhododendron spp. and Pieris japonica were the most frequently reported plants. Common clinical signs and treatment were summarized. Retching, regurgitation, and vomiting were common and might be suggestive of plant poisoning in ruminants. Reports on grayanotoxin poisoning in animals must be improved to address existing knowledge gaps.