Footrot outbreak in a sheep herd in the Araçatuba region, state of S. Paulo, Brazil

Abstract

Footrot is a multifactorial, contagious, bacterial disease that starts in the interdigital space and spreads to the horny parts of the feet, particularly in sheep. Dichelobacter nodosus (Bacteroides nodosus) is the causing agent and main pathogen of this complex disease. The classification of footrot as virulent or benign is based on the proteolytic characteristics of the bacteria and extension of epidermal matrix involvement, and hence the degree of hom separation. The disease is particularly prevalent in the Brazilian South states and is found less often in the state of S. Paulo. The objective of this study was to report an outbreak of the virulent form of the disease in a 400-sheep farm in the region of Araçatuba, after some animals from the state of Paraná were introduced. The horn lesions were initially observed in 15 animals and during the treatment period all animals had been infected. Lesions were found in the epidermal matrix, with a high degree of tissue destruction resulting in separation and growth deformation of the horny tissues. The lesions were assessed and the tissue destruction graded as mild (5% of the animals), moderate (10%) or severe (85%). The four feet were affected in most animals. The treatment included hoof trimming, vaccination with an inactivated suspension of D. nodosus and use of footbath containing 10% CuSO4 + 3% formalin. Although the disease was considered to be virulent, the treatment was inexpensive and effective as 98.75% of the animals recovered.