Leptospirosis Infection in Sheep and Characterization of the Renal Inflammatory Response.

Abstract

Carvalho S.M., Gon alves L.M.F., Macedo N.A., Goto H., Silva S.M.M.S., Mineiro A.L.B.B., Kanashiro E.H.Y. & Costa F.A.L. 2011. [Leptospirosis Infection in Sheep and Characterization of the Renal Inflammatory Response.] Infeccao por leptospiras em ovinos e caracterizacao da resposta inflamatoria renal. Pesquisa Veterinaria Brasileira 31(8):637-642. Departamento de Clinica e Cirurgia Veterinaria, Centro de Ciencias Agrarias, Universidade Federal do Piaui, Campus Socopo, Teresina, PI 64046-550, Brazil. E-mail: fassisle@gmail.com Lepitospirosis is a serious worldwide distribution disease which affects man and other animals. The infection is generally asymptomatic in animals. In cases whose symptoms are present, symptoms are similar to other infections. In the present study serum samples from 119 sheep and their kidneys were collected during their slaughter in outdoor markets in the city of Teresina, Piaui, Brazil. The Microscopic Agglutination Test (MAT) obtained 34 positive serological samples for one or more Leptospira spp. serovar with occurrence rate of 28.6% of leptospiral antibodies. There were 23 cases of infection for a single serovar, and 11 cases with coagglutination for two or more serovars. Autumnalis had the highest occurrence (29.4%) among the pathogenic serovars. The histopathological analysis of 36 kidney fragments revealed tubulo-interstitial alterations in 33 (91.7%) positive animals. Tubular lesions were observed in 20 (55.5%) positive animals. The Warthin Starry staning revealed the presence of Leptospira in 8 (22.20%) of the 36 positive samples. The immunoperoxidase staining revealed the presence of Leptospira in 12 (60%) of 20 positive samples. The inflammatory infiltrate in the positive animals was significantly more evident in the cortical-medullar and cortical regions than in the medullar region (p=0.000), however, there was no difference between positive and negative animals. The presence of hyaline casts in the proximal tubules was significantly higher in positive animals compared to the negative ones (p=0.0001). Discrete lesion was observed in glomeruli. In conclusion, the results from this study showed that sheep which are positive for Leptospira present tubulo-intersticial renal lesions with the presence of Leptospira in the tubules, conferring to these animals the condition of asymptomatic carriers.