ABSTRACT
The epidemiological characteristics of bovine leptospirosis in animals and herds in Mato Grosso do Sul were investigated to determine parameters such as disease frequency and the serovars reactant in beef cattle herds. A total of 4,629 beef cattle herds were examined against 33 Leptospira spp. serovars. The serum samples were submitted to the microscopic agglutination test (MAT) for the serological diagnosis of leptospirosis. The MAT results showed that 3,814 (82.39%) of the 4,629 animals evaluated were seropositive for the bacterium, with serological reactions mainly to serogroup Sejroe, serovar Wolffi (36.49%). The observed high frequency of reactive animals demonstrates the relevance of the infection. Therefore, general and specific measures should be implemented to contain and/or prevent infection of the animals in the studied region.(AU)
Foi realizado um inquérito epidemiológico da leptospirose em bovinos de rebanhos de corte do estado de Mato Grosso do Sul, de modo a determinar a frequência e as sorovariedades reagentes. Para isso, foram examinados 4.629 bovinos de corte, com uma coleção de 33 sorovariedades de Leptospira, por meio da prova de Soroaglutinação Microscópica (MAT). Dos 4.629 animais examinados, 3.814 (82,39%) foram reagentes com reações predominates para o sorogrupo Sejroe, sorovar Wolffi (36,49%). Assim, a alta frequência de animais reagentes encontrada justifica a implantação de medidas gerais e específicas para conter e/ou prevenir a infecção nos animais dessa região.(AU)
Subject(s)
Animals , Cattle , Cattle/microbiology , Seroepidemiologic Studies , Leptospirosis/epidemiologyABSTRACT
BACKGROUND: Toxoplasma gondii is a protozoan parasite that causes congenital toxoplasmosis by transplacental transmission. Parasite strains are genetically diverse and disease severity is related to the genotype. In Uberlândia city, Brazil, two virulent strains were isolated: TgChBrUD1 and TgChBrUD2. Congenital toxoplasmosis is more prevalent in South America compared to Europe, and more often associated with severe symptoms, usually as a result of infection with atypical strains. METHODS: Considering that T. gondii has shown high genetic diversity in Brazil, the effectiveness of traditional treatment may not be the same, as more virulent strains of atypical genotypes may predominate. Thus, the aim of this study were to evaluate the Brazilian strain infection rate in human villous explants and the azithromycin efficacy with regard to the control of these strains compared to traditional therapy. Villi were infected with RH, ME49, TgChBrUD1 or TgChBrUD2 strains and treated with azithromycin, spiramycin or a combination of pyrimethamine plus sulfadiazine. The villous viability was analyzed by LDH assay and morphological analysis. Parasite proliferation, as well as production of cytokines was analyzed by qPCR and ELISA, respectively. Statistical analysis was performed using the GraphPad Prism 5.0. RESULTS: The treatments were not toxic and TgChBrUD1 infected villi showed a higher parasite burden compared with others strains. Treatments significantly reduced the intracellular proliferation of T. gondii, regardless of the strain. TgChBrUD1-infected villi produced a larger amount of MIF, IL-6 and TGF-ß1 compared with other infected villi. Azithromycin treatment increased MIF production by RH- or TgChBrUD2-infected villi, but in ME49- or TgChBrUD1-infected villi, the MIF production was not altered by treatment. On the other hand, azithromycin treatment induced lower IL-6 production by ME49- or TgChBrUD1-infected villi. CONCLUSIONS: Azithromycin treatment was effective against T. gondii Brazilian strains compared with conventional treatment. Also, the TgChBrUD1 strain replicated more in villi and modulated important cytokines involved in parasite control, showing that different strains use different strategies to evade the host immune response and ensure their survival.
Subject(s)
Azithromycin/pharmacology , Coccidiostats/pharmacology , Cytokines/metabolism , Placenta/parasitology , Toxoplasma/drug effects , Brazil , Female , Humans , Pregnancy , Pregnancy Trimester, ThirdABSTRACT
Considering that Toxoplasma gondii has shown high genetic diversity in Brazil, the aim of this study was to determine whether Calomys callosus chronically infected by the ME-49 strain might be susceptible to reinfection by these Brazilian strains, including vertical transmission of the parasite. Survival curves were analyzed in non-pregnant females chronically infected with ME-49 and reinfected with the TgChBrUD1 or TgChBrUD2 strain, and vertical transmission was analyzed after reinfection of pregnant females with these same strains. On the 19th day of pregnancy (dop), placentas, uteri, fetuses, liver, spleen, and lung were processed for detection of the parasite. Blood samples were collected for humoral and cellular immune response analyses. All non-pregnant females survived after reinfection and no changes were observed in body weight and morbidity scores. In pregnant females, parasites were detected in the placentas of ME-49 chronically infected females and reinfected females, but were only detected in the fetuses of reinfected females. TgChBrUD2 reinfected females showed more impaired pregnancy outcomes, presenting higher numbers of animals with fetal loss and a higher resorption rate, in parallel with higher levels of pro-inflammatory cytokines and IgG2a subclass antibodies. Vertical transmission resulting from chronic infection of immunocompetent C. callosus is considered a rare event, being attributed instead to either reactivation or reinfection. That is, the pregnancy may be responsible for reactivation of the latent infection or the reinfection may promote T. gondii vertical transmission. Our results clearly demonstrate that, during pregnancy, protection against T. gondii can be breached after reinfection with parasites belonging to different genotypes, particularly when non-clonal strains are involved in this process and in this case the reinfection promoted vertical transmission of both type II and Brazilian T. gondii strains.
