Surto de intoxicação por monensina sódica em equinos associada a consumo de suplemento mineral à base de melaço de cana-de-açúcar / Outbreak of monensin sodium poisoning in horses associated with consumption of mineral supplement based on sugarcane molasses

ABSTRACT

Background: Sodium monensin is a molecule of the group of ionophores antibiotics (IAs) of the polyether carboxylic typeproduced from the fermentation of Streptomyces cinnamonensis. Cases of IA poisoning in animals usually occur accidentally. Fatal poisoning in horses, a non-target species and with particular sensitivity usually occurs by the consumption ofthese products from the toxic dose of 2-3 mg/kg. This report aims to describe the epidemiological and clinical-pathologicalaspects of an outbreak of ionophore antibiotic poisoning in horses due to the consumption of mineral supplementationindicated for ruminants based on sugarcane molasses.Case Two horses were necropsied. During necropsy, fragments of various organs were collected and fixed in 10% bufferedformalin, routinely processed for histology and stained with hematoxylin and eosin. The information obtained from the animaltrainer was that 19 horses received approximately 25 kg of low moisture mixture based on sugarcane molasses, enriched withmacro and micro minerals, vitamins and additives containing 1000 mg of monensin/kg in the trough. One day after receivingthe product, five horses began to develop ataxia, reluctance to move, difficulty of accompanying the herd and arising. Out ofthe five, three died after three days of evolution, one after six days (equine 1) and another after 15 days (equine 2) [morbidity 26.31%]. At necropsy, diffuse pallor was observed in the gluteus medius, quadriceps femoris, semimembranosus, bicepsbrachii and deep pectoral muscles. Microscopically the muscle fibers were tumefied with hypereosinophilic sarcoplasmof homogeneous appearance and with loss of striations, pynotic or absent nuclei (necrosis). Multifocal areas of fibers withsarcoplasmic fragmentation were observed, with clusters of irregular eosinophilic debris, flake (floct necrosis) or granule(granular necrosis)...