Leptospirosis seroprevalence and risk factors for sheep in Maranhão state, Brazil.

This study was conducted to determine leptospirosis seroprevalence in sheep and their spatial distribution as well as identify risk factors associated with seropositivity in sheep from 37 herds and 11 municipalities in the Presidente Dutra microregion, Maranhão state, Brazil. We analyzed 379 blood serum samples using a Microscopic Agglutination Test (MAT). The individual seroprevalence was 32%. Of the 37 herds studied, 30 (81%, 95% CI 69-94%) had at least one seropositive animal. In seven municipalities, we observed infection in 100% of the herds. The serovars recorded were Grippotyphosa (67%), Wollfi with Hardjo (9%), Bratislava (9%), Hardjo (5%), Icterohaemorrhagiae (5%), Pomona (2%), Castellonis (2%) and Copenhageni (0.8%). We concluded that the Leptospira spp. in sheep is widespread in the area of sheep farms in Maranhão state, and a risk factor is the animals' water source.

Pesquisa de aglutininas, antígeno de leptospiras e apoptose em rim de suínos naturalmente infectados por Leptospira spp. / Search agglutinins, leptospires antigen and apoptosis in the kidney of swine naturally infected with Leptospira spp.

Soro e rim de 75 suínos mestiços sem raça definida, criados em sistema extensivo e abatidos em Timon (MA) e Teresina (Piauí), Brasil, duas cidades separadas pelo Rio Parnaíba e 75 suínos mestiços de um sistema de criação em confinamento, filhos de Landrace, Large White e/ou Duroc foram utilizados neste estudo. Das 150 amostras analisadas pela prova de Soroaglutinação Microscópica (SAM), sete foram reagentes e o sorovar Icterohaemorrhagiae (42,86 por cento) foi o mais frequente. Uma comparação entre os dois sistemas para examinar uma predisposição para infecção para Leptospira spp. mostrou que a suscetibilidade foi maior nos animais criados extensivamente do que naqueles criados em confinamento (teste χ2, p<0,05). A presença de infiltrado inflamatório foi significantemente maior nos animais soropositivos comparados aos soronegativos (p<0,05, Teste U de Mann-Whitney). A análise morfométrica mostrou Leptospira spp. e o antígeno de leptospira apenas nos animais soropositivos (p<0,05, teste de U de Mann-Whitney). Apoptose em células epiteliais tubulares foi significantemente mais evidente nos animais infectados comparados aos não infectados (p<0,05, Teste U de Mann-Whitney). Uma eventual associação de antígeno de Leptospira e células epiteliais em apoptose sugere um provável mecanismo de lesão renal na leptospirose suína.

Serum and kidney of 75 mixed bred swine (no definite breed) reared in an extensive system and slaughtered in Timon (state of Maranhão) and Teresina (state of Piauí), Brazil, two cities separated from each other by the Parnaiba River, and 75 crossbred swine from a confinement rearing system, sired by Landrace, Large White and/or Duroc, were used in this study. From the 150 analyzed samples for the microscopic agglutination test (MAT), seven were reagents and the serovar Icterohaemorrhagiae (42.86 percent) was the most frequent. A comparison between both systems to verify a predisposition to Leptospira spp. infection showed that susceptibility was greater in extensively reared animals than in those bred in confinement (χ2 test, p<0.05). Inflammatory infiltrates covered an average area larger in the seropositive revealing a significant difference for the seronegative animals (p<0.05, Mann-Whitney U-Test). Morphometric analysis showed Leptospira spp. and antigen labeling in seropositive animals only (p<0.05, Mann-Whitney U-test). Apoptosis in tubular epithelial cells was significantly more evident in the infected animals compared to uninfected. The rearing system and environment conditions are an important factor in the susceptibility of swine to Leptospira spp. infection. An eventual association of leptospira antigen and apoptotic cells suggests a probable mechanism of renal injury at leptospirosis.