Intoxicação por antibióticos ionóforos e leucoencefalomalácia concomitantes pelo consumo de ração comercial contaminada em equinos / Concurrent ionophore poisoning and leukoencephalomalacia by consumption of contaminated commercial ration in horses

ABSTRACT

Background: Equidae nutritional change increased the frequency of diseases due to inappropriate administration and storage of rations. Although there are reports of ionophore poisoning (IP) and leukoencephalomalacia (LEM) in equidae from Brazil, the concurrent occurrence of both diseases by the same contaminated commercial ration is unprecedented. Therefore, the present paper aims to describe the epidemiological, clinical, laboratorial and pathological findings of concurrent IP and LEM outbreaks in horses.Cases Eleven farmers from seven different locations in Distrito Federal, Midwestern Brazil, reported sudden clinical signs in 27 horses after the ingestion of commercial pelleted ration. During the farm visits, it was found that the ration brand and batches were identical, and macroscopic evaluation revealed no abnormalities. Eight horses were clinically evaluated and presented hyporexia, apathy, hypermetria, ataxia, dehydration, dyspnea, tongue hypotonia, muscle tremors, tachycardia, facial hypoalgesia, dysphagia, and sporadic or permanent recumbence. Laboratorial changes were restricted to creatine phosphokinase (mean 1,573.4 ± 16.9 IU/L) and gammaglutamyl transferase (mean 34.85 ± 29.14 IU/L) serum increases. Pathological evaluation has performed in eight horses presenting pallor and whitish striations in the gluteal, longissimus dorsi, femoral quadriceps muscles and myocardium, varying from mild to moderate. One horse also showed a soft and yellowish focal area on the right temporal lobe white matter. Microscopically, alterations in skeletal and cardiac muscle tissues included striated muscle fibers and cardiomyocytes segmental necrosis, characterized by sarcoplasmic fragmentation with clusters of eosinophilic debris, cellular retraction and hypereosinophilia. Histological alterations in the central nervous system of one horse were characteristic of LEM.[...]