Avaliação do teste de polarização fluorescente para discriminar títulos sorológicos de bezerras vacinadas com amostras B19 DE Brucella abortus

Exportado OPUSMade available in DSpace on 2019-08-11T03:31:12Z (GMT). No. of bitstreams: 1 disserta__o_formatada_guilherme_faria.pdf: 288089 bytes, checksum: 43cac8837929681ddc1ef8a76750db17 (MD5) Previous issue date: 6Os testes preconizados pelo Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose (PNCEBT) para o diagnóstico sorológico da brucelose foram comparados com o teste de Polarização Fluorescente quanto à capacidade de discriminar títulos sorológicosdecorrentes da vacinação com B19. Foram utilizadas 93 bezerras provenientes de um rebanho leiteiro certificado como livre de brucelose e tuberculose pelo Ministério da Agricultura Pecuária e Abastecimento (MAPA). As amostras de soro sanguíneo foram coletadas imediatamenteantes da vacinação, e após 3, 6, 9 e 12 meses de vacinadas. Foram calculados os valores de especificidade para cada teste, assim como a concordância e o índice kappa entre os testes. A correlação da incidência de resultados positivos na Fixação de Complemento com a idade à vacinação e o grau de sangue zebu foi avaliada através do coeficiente de Spearman e por um estudo de coorte. Os valores de especificidade encontrados nas diferentes datas de coleta variaram de 41,94% a 94,57%, 62,37% a 97,83%, 69,89% a 97,83%, e 76,34% a 95,65% para os testes do Antígeno Acidificado Tamponado (AAT), 2-Mercaptoetanol (2-ME), Fixação de Complemento (FC) e Polarização Fluorescente (FPA) respectivamente. Quando avaliada a concordância entre os testes, os melhores valores encontrados foram entre a FC e o 2-ME, considerada perfeita após os 9 meses da vacinação (k=1,0). A FPA apresentou boa concordância com os dois testes confirmatórios preconizados pelo PNCEBT somente após os 9 meses da vacinação (k>0,6). Foi observada uma incidência significativamente maior de resultados positivos na FC naquelas bezerras de maior grau de sangue zebu e vacinadas mais tardiamente.Tests for serologic diagnosis of bucellosis recommended by the Brazilian National Program for the Control and Eradication of Bovine Brucellosis and Tuberculosis (PNCEBT) were compared with the Fluorescent Polarization Assay regarding the ability to discriminate serologic titles arising from the S19 vaccination. The 93 calves used in this experiment were originated from a brucellosis-free dairy farm according to the Brazilian Ministry of Agriculture, Livestock, and FoodSupply (MAPA). The serum samples were obtained just before the vaccination and 3, 6, 9, and 12 months after that. Specificity values for each tests as well agreements and Kappa index values were calculated. The positive correlation between Complement Fixation Test and age atvaccination and Zebu blood degree was evaluated by Spearmen Coefficient and Cohort Study. The Specificity coefficient ranged from 41.94 to 94.57%, 62.37 to 97.83%, 69.89 to 97.83%, and 73.34 to 95.65%, respectively, for the Rose-Bengal Test (RBT), 2-Mercaptoetanol (2-ME),Complement Fixation Test (CFT) and Fluorescent Polarization Assay (FPA). Regarding to the agreement between the tests, the bests values were obtained for the CFT and 2-ME relationship, that was considered perfect nine months after vaccination (k=1.0). The FPA test only presents good agreement with two recommended confirmatory tests of PNCEBT nine months after vaccination (k>0.6). Calves with higher Zebu blood degree and late vaccinated presented significantly higher positive result

Retrospective Investigation in Horses with Encephalitis Reveals Unnoticed Circulation of West Nile Virus in Brazil

During these past years, several studies have provided serological evidence regarding the circulation of West Nile virus (WNV) in Brazil. Despite some reports, much is still unknown regarding the genomic diversity and transmission dynamics of this virus in the country. Recently, genomic monitoring activities in horses revealed the circulation of WNV in several Brazilian regions. These findings on the paucity of genomic data reinforce the need for prompt investigation of WNV infection in horses, which may precede human cases of encephalitis in Brazil. Thus, in this study, we retrospectively screened 54 suspicious WNV samples collected between 2017 and 2020 from the spinal cord and brain of horses with encephalitis and generated three new WNV genomes from the Ceará and Bahia states, located in the northeastern region of Brazil. The Bayesian reconstruction revealed that at least two independent introduction events occurred in Brazil. The first introduction event appears to be likely related to the North American outbreak, and was estimated to have occurred in March 2013.The second introduction event appears to have occurred in September 2017 and appears to be likely related to the South American outbreak. Together, our results reinforce the importance of increasing the priority of WNV genomic monitoring in equines with encephalitis in order to track the dispersion of this emerging pathogen through the country