Leptospirosis and toxoplasmosis are diseases that may affect man and domestic and wild animals. They also have wide geographical distributions and thus cause large public health issues. The objective of the current study was to conduct leptospirosis and toxoplasmosis seroepidemiology in horses used for animal traction in small rural propertiesof the municipality of Umuarama, in northwest region of the state of Paraná, Brazil. Blood samples were collected from 312 horses from 87 small farms. Microscopic agglutination tests (MAT) and indirect immunofluorescence (IIF) analysis were performed on sera to detect leptospirosis and toxoplasmosis, respectively. These were performed in conjunction with an epidemiological questionnaire. The MAT results included 180 (57.69%) samples that were considered reactive with titers between 100 and 12800 for one or more serovars. Thirty-three (10.57%) samples subjected to IIF were considered reactive, with titers ranging between 64 and 1024. From the analyzed variables, contact with wild animals (p= 0.012) and animal exchange between properties (p = 0.004) were associated with toxoplasma infection. The study revealed that horses in the northwestern region of Paraná were exposed to Leptospira spp. and Toxoplasma gondii, with an insignificant implication of the animals' clinical condition; however, since it is possible for animals to transmit infection to other animals as well as humans via the intermittent shedding of leptospires through urine into the environment, it may be considered a problem of one health. As for the presence of T. gondii antibodies, these horses played the role of sentinel of the infection. Environmental sanitation measures, serological studies of herds, control of rodents and felids on properties, and the dissemination of information about these diseases are relevant for disease control at the study site.A leptospirose e a toxoplasmose são enfermidades de ampla distribuição geográfica e podem acometer o homem, animais domésticos e selvagens que causam elevados problemas para a saúde pública. O objetivo deste trabalho foi realizar a soroepidemiologia da leptospirose e toxoplasmose em equinos utilizados como tração animal de pequenas propriedades rurais do município de Umuarama, região noroeste do estado do Paraná, Brasil. Foram coletadas amostras de sangue de 312 equinos de 87 pequenas propriedades rurais. Para detectar a leptospirose e toxoplasmose os soros foram submetidos às técnicas de soroaglutinação microscópica (SAM) e imunofluorescencia indireta (IFI) respectivamente associada ao preenchimento de um questionário epidemiológico. Na SAM, 180 (57,69%) amostras foram consideradas reagentes apresentando títulos entre 100 e 12800, para um ou mais sorovares. Na IFI, 33 (10,57%) amostras foram consideradas reagentes com títulos de 64 a 1024. Em relação às variáveis analisadas, o contato com animais selvagens (p= 0,012) e troca de animais entre propriedades (p= 0,004) foram associados à infecção toxoplásmica. O estudo revela que os equinos da região noroeste do Pa...
