Epidemiological, clinical and pathological aspects of an outbreak of periodontitis in sheepan outbreak of periodontitis in sheep

Abstract

The objective of this study was to describe the epidemiological, clinical and pathological aspects of an outbreak of periodontitis in sheep that occurred on a rural property in Benevides, in the state of Pará, Brazil. The first clinical signs of this disease in the herd - visible nodular swollen mandible - were observed about one month after the sheep began grazing on a recently renovated Panicum maximum cv. Massai pasture; the animals were also supplemented with elephant grass (Pennisetum purpureum). From the 545 adult Santa Ines, Dorper, Texel and crossbred sheep, 20 (3.7%) showed facial bulging, particularly of the mandible. These 20 sheep, which were generally over 36 months of age, had low body condition scores as well as dull and ruffled coats; many of them had loose or missing pre, upper or lower molars, showed the formation of abscesses and fistulas, exhibited pain upon palpation and had difficulty chewing. In the same herd, the prevalence of periodontal lesions at the premolars and molar teeth was evaluated via post-mortem examination of 39 young and 17 adult sheep. In 51.3% (20/39) of adolescents and in 100% of adults, periodontal lesions were found at least at one tooth of the dental arch, with unilateral or bilateral periodontal lesions at the maxillary and mandibular teeth. Histopathological analysis of 13 sheep revealed pyogranulomatous inflammation. The second and third maxillary premolars were the teeth that were most affected in young animals, whereas the third pre-molar and the molars, of the maxilla and mandible, were most often affected in adults. These lesions led to severe bone destruction, alterations in the dental arch, occlusion, tooth loss and periodontal abscesses. The epidemiological and clinic-pathological characteristics of this periodontitis outbreak, described here for the first time in sheep in Brazil, were similar to those for bovine periodontitis ("cara inchada").