ABSTRACTWe have evaluated the efficacy of short-interfering RNAs targeting the nucleoprotein gene and also the brain immune response in treated and non-treated infected mice. Mice were inoculated with wild-type virus, classified as dog (hv2) or vampire bat (hv3) variants and both groups were treated or leaved as controls. No difference was observed in the lethality rate between treated and non-treated groups, although clinical evaluation of hv2 infected mice showed differences in the severity of clinical disease (p = 0.0006). Evaluation of brain immune response 5 days post-inoculation in treated hv2 group showed no difference among the analyzed genes, whereas after 10 days post-inoculation there was increased expression of 2',5'-oligoadenylate synthetase 1, tumor necrosis factor alpha, interleukin 12, interferon gamma, and C-X-C motif chemokine 10 associated with higher expression of Ngene in the same period (p < 0.0001). In hv2 non-treated group only higher interferon beta expression was found at day 5. The observed differences in results of the immune response genes between treated and non-treated groups is not promising as they had neither impact on mortality nor even a reduction in the expression of N gene in siRNA treated animals. This finding suggests that the use of pre-designed siRNA alone may not be useful in rabies treatment.

Brucelose e leptospirose são enfermidades bacterianas amplamente disseminadas e o cão é importante fonte de infecção e reservatório para ambas, podendo eliminar o agente no meio ambiente, e transmiti-lo para humanos e/ou outros animais. O presente estudo teve como objetivo pesquisar a ocorrência de cães reagentes para anticorpos contra Leptospira spp., Brucella canis e B. abortus em Belém e Castanhal, Pará, Amazônia, Brasil. Foram colhidas de forma aleatória 156 amostras no município de Belém e 158 amostras em Castanhal. A pesquisa de anticorpos anti-B. canis foi realizada pela técnica de Imunodifusão em Gel de Ágar (IDGA) com e sem tratamento do soro com 2-mercaptoetanol (IDGA-2ME) e para pesquisa de anticorpos anti-B. abortus foi utilizada a técnica de Soroaglutinação Rápida com antígeno acidificado tamponado (AAT). Para pesquisa de anticorpos contra-Leptospira spp. utilizou-se a Técnica de Aglutinação Microscópica (MAT). Nenhum animal reagiu para Brucella abortus e um animal foi reagente para B. canis na IDGA, porém foi negativo na IDGA-2ME. Dezessete por cento dos cães (47/274) apresentaram anticorpos contra-Leptospira spp., com predominância do sorovar Canicola. Os cães de Belém e Castanhal não são fontes de infecção para B. abortus e B. canis, no entanto são reservatórios de diferentes sorovares de Leptospira spp.

Brucellosis and leptospirosis are widely spread bacterial infections and dogs are the most important source of infection and reservoir for diseases. Dogs can disseminate the agents in the environment and transmit them to humans and/or other animals. The objective of this study was assess the occurrence of reactive to antibodies anti-Leptospira spp., Brucella canis and B. abortus in Belém and Castanhal, State of Pará, Amazon, Brazil. A total of 156 samples were randomly collected in the city of Belém and 158 samples in Castanhal. The anti-B. canis antibodies research was performed by Agar Gel Immunodiffusion (AGID) with and without 2-mercaptoethanol serum treatment (AGID-2ME). To assess the anti-B. abortus antibodies, the technique of Fast Seroagglutination with buffered acidified plate antigen (BAPAT) was used. For anti-Leptospira spp. antibodies research, the Microscopic Agglutination Technique (MAT) was used. No animal reacted to Brucella abortus and one animal was reactive to B. canis at the AGID, but it was negative to the AGID-2ME test. Seventeen percent of dogs (47/274) presented anti-Leptospira spp. antibodies, with prevalence of serovar Canicola. The dogs from Belém and Castanhal are not source of infection for B. abortus and B. canis, however, they are reservoirs for different serovars of Leptospira spp.