Periódicos Brasileiros em Medicina Veterinária e Zootecnia

Challenges on the follow-up experimental leptospiral infection in sheep

Rosa, Matheus Costa daRocha, Bruno RibeiroCorreia, LucasMartins, GabrielDellagostin, Odir AntônioLilenbaum, Walter

Background: Leptospirosis is currently a source of significant economic losses in the agribusiness; as such, experimentalstudies on this infection are required to develop a better understanding of the pathogenesis, treatment, and immunoprophylaxisof the disease. Sheep may represent a good model for ruminants in such models. Despite the extent of the studies that hasbeen conducted thus far, researchers have yet to reach a consensus on the experimental practices to apply for leptospirosisin this animal species, and several gaps in understanding remain. To bridge these gaps, the present study aimed to assessthe usage of several tools for the monitoring of experimental leptospirosis in sheep.Materials, Methods & Results: Twelve Santa Ines sheep of different ages were each allocated to one of four groups (A, B,C, and D). The subjects in groups A, B, and C received different doses of Leptospira interrogans serogroup Icterohemorrhagiae by intraperitoneal route, 1x102, 1x105, and 1x108 respectively. Group D was the control. Hematological, biochemicaland clinical parameters were evaluated daily. Serology by microscopic agglutination test (MAT) and PCR were performedto evaluate the infection status. The most remarkable clinical signs were fever (41ºC) and dehydration, and acute pain(cub). Two animals from Group C presented leukocytosis. Only those in Group C exhibited positive results according toserology, while positivity in PCR was observed in animals in groups A and C. The results of the experiment indicated thatsheep may be experimentally infected and can, therefore, be used as a model for leptospirosis in ruminants. Clinical signscannot be considered to represent a reliable parameter for evaluating the development of leptospirosis in experimentallyinfected sheep. We recommend the use of urine PCR and serology to confirm the infection in... (AU)

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