Polioencephalomalacia in Buffaloes in the Amazon Biome

Abstract

The epidemiological and clinical pathological aspects of polioencephalomalacia (PEM) in five buffaloes (buffaloes 01 to 05) in the amazon biome are described. Epidemiological data were obtained during the clinical visit in which the animals with clinical signs compatible with polioencephalomalacia were submitted to a general and specific clinical examination of the nervous system. During the necropsy of the five animals, the intensity and location of the lesions were evaluated and fragments from different organs were collected and fixed in 10% buffered formalin and sent to the Pathological Anatomy Sector of the Federal Rural University of Rio de Janeiro for histopathological examination. Of the five studied animals, all were of the Murrah breed, four male and one female, with ages ranging from two months to one year. Two buffaloes (buffalo 01 and 02) were from the municipality of Castanhal, Pará, kept in an extensive breeding system on Urochloa brizantha pasture. Buffaloes 03 and 04 belonged to a property located in the municipality of Cachoeira do Arari, Marajó Island, Pará, and buffalo 05 was from a property located in the municipality of Itaubal, state of Amapá, all of them were raised in an extensive system in flooded of native pasture. At the clinical examination, all buffaloes had a body score between 2.5 and 3 (scale from 1 to 5), and there was noted decreased alertness, postural changes, marked hypermetria when stimulated to move, total or partial blindness demonstrated by colliding to the corral structures, head pressing and circumduction of the hindquarters when supported on the forelimbs, opisthotonos, muscle tremors, convulsions, paddling movements, sialorrhea, decrease in palpebral and pupillary reflexes and eyeball rotation placing the pupillary slit in a vertical position. At necropsy, mild lesions characterized by edema and flattening of the cerebral convolutions were observed. Histopathological examination showed laminar necrosis of the cerebral cortex. The diagnosis of polioencephalomalacia was based on epidemiological, clinical-pathological, and histopathological findings, similar to findings in other ruminants. The cause of polioencephalomalacia in the studied buffaloes was not established, which indicates the need for further studies to elucidate this disease in the species, mainly in the Amazon region.