Toxic Gastritis in a Llama (Lama glama) Caused by Spontaneous Baccharis coridifolia DC. (Mio-mio) Poisoning in the Santa Catarina Plateau, Brazil

Abstract

This report describes the first known spontaneous case of B. coridifolia poisoning in a domesticated llama. In August 2023, the death of a 10-month-old female llama was reported on a farm in the Santa Catarina Plateau, Brazil. The affected llama had been acquired 2 months earlier from Paraná and initially kept with sheep on ryegrass pasture. One day before death, it was moved to a native field heavily invaded with B. coridifolia. Clinical signs included polydipsia and muscle tremors, progressing rapidly to death approximately 14 h after the onset of clinical signs. At necropsy, the 1^st and 2^nd gastric compartments (C1 and C2) contained abundant fibrous ingesta and exhibited mild mucosal congestion. In the 3^rd gastric compartment (C3), mild to moderate congestion, predominantly affecting the caudal region, was observed. Histopathology revealed marked diffuse mucosal necrosis with inflammatory infiltrates predominantly composed of neutrophils and macrophages, and mild edema in the aglandular portions of C1 and C2. In C3, mild to moderate congestion was observed. Additional findings included pulmonary congestion and edema, renal congestion, and centrilobular hepatocellular degeneration. Specimens of B. coridifolia collected from the property were submitted to the Herbarium Lages of the State University of Santa Catarina (LUSC) for botanical confirmation. The epidemiological, clinical, and pathological findings supported the diagnosis of B. coridifolia (mio-mio) toxicosis.This case underscores the importance of proper pasture management and careful monitoring when relocating animals to areas containing known toxic plants.