The aim of this study was to select different genotypes of Lippia sidoides with the highest activity against larvae and engorged females of the tick Rhipicephalus (Boophilus) microplus. The germplasms studied were LSID006, LSID102, LSID103 and LSID104. The LSID104 genotype, that presented carvacrol as a major constituent, was the germplasm with the worst larvicide effect (LC50 2.99 mg/mL). The LSID006 genotype was the least effective against engorged females (LC50 12.46 mg/mL), and it was chemically similar to the LSID102 genotype, which presented the highest acaricide activity (LC50 2.81 mg/mL). We conclude that chemical similarity of the germplasms was not correlated with acaricide activity against R. (B.) microplus. The essential oil of L. sidoides is a potent natural agent. However, the findings of this work provide a better understanding for product development based on this natural product, which must consider synergic effects or the action of minor compounds.

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Bovine neosporosis is a parasitic disease caused by the protozoan Neospora caninum, which is one of the main pathogens that cause abortions in cattle worldwide. It is responsible for large losses in dairy and beef cattle, especially with regard to the expenses associated with decreased productivity and increased discard. In the State of Maranhão, the occurrence of this parasite has already been confirmed in the dairy cattle of three microregions that make up the state’s dairy industry and in small ruminants of the municipalities of Amarante do Maranhão and Buritirana. This fact justifies the importance of determining the presence of N. caninum in cattle slaughtered in the slaughterhouses of the Island of São Luís, to help control the parasitic cycle in the cattle production system of the region under study, and the importance of its diagnosis. The objective of the research was to conduct a histopathological and immunohistochemical characterization of bovine placentas infected with N. caninum collected in slaughterhouses. Sixteen placenta samples from cows were randomly selected at the slaughterhouses of the city of São Luís for histological analysis and immunohistochemistry. Results showed that 31% of the placentas presented histopathological changes such as: inflammatory process, edema, hemorrhage and presence of hemosiderin. All slides with histopathological changes showed immunolabeling for N. caninum.

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