Molecular epidemiology of an outbreak of bovine rabies in central Rio Grande do Sul, Brazil, 2012/Epidemiologia molecular de surto de raiva bovina na regiao central do Rio Grande do Sul, 2012

• Published in: Ciência rural 2014-05, Vol.44 (5), p.834
• Main Authors: Kanitz, Fabio Adriano, Kowalski, Ananda Paula, Batista, Helena Beatriz de Carvalho Ruthner, Carnieli, Jr., Pedro, Oliveira, Rafael de Novaes, Weiblen, Rudi, Flores, Eduardo Furtado
• Format: Article
• Language: Spanish
• Subjects: Analysis; Bats; Epidemiology; Livestock; Phylogeny; Rabies; Viral antigens
• ISSN: 0103-8478

Rabies is an infectious disease of the central nervous system of mammals caused by rabies virus (RabV), generally transmitted by the bite of rabid animals. In Brazil, vampire bats Desmodus rotundus are the main reservoirs of RabV for livestock. The present study describes a molecular and epidemiological investigation of outbreaks of bovine rabies occurring in the central region of Rio Grande do Sul state, Brazil, between May and August 2012. In this period, 45 cases suspected of rabies were reported in 22 small herds, located within a 4.7km range, in the county of Pinhal Grande. From these, 32 samples were submitted to rabies diagnosis and RabV and/or viral antigens were identified in 27 samples. Subsequently, 11 brain samples were submitted to reverse transcription/polymerase chain reaction (RT-PCR) for the nucleoprotein gene (N) followed by nucleotide sequencing and phylogenetic analysis. Seven out of 11 samples yielded identical sequences; one presented a synonymous, non-coding mutation, indicating a likely common origin of the virus. However, three other samples presented nucleotide mutations which resulted in amino acid changes, suggesting a different origin of the virus. In summary, these results suggest that RabV strains of different origin/lineages co-circulate in the region and were involved in the outbreaks. Investigations on the circulation of both genotypes in bats in the region are currently underway. Key words: rabies, Desmodus rotundus, outbreaks, phylogenetic analysis. A raiva e uma doenca infecciosa do sistema nervoso central de mamiferos causada pelo virus da raiva (RabV), geralmente, transmitido pela mordedura de animais infectados. No Brasil, os morcegos hematofagos Desmodus rotundas sao as principais fontes de infeccao do RabVpara bovinos e equinos. Este artigo descreve uma investigacao epidemiologica e molecular de surtos de raiva ocorridos na regiao central do Rio Grande do Sul, entre maio e agosto de 2012. Nesse periodo, 45 casos suspeitos de raiva foram relatados em 22 pequenos rebanhos, localizados dentro de um raio de 4,7km, no municipio de Pinhal Grande. Desses, 32 amostras foram submetidas para diagnostico da raiva, sendo que o RabV e/ou antigenos virais foram identificados em 27 amostras. Em um segundo momento, 11 amostras foram submetidas a transcricao reversa/reacao em cadeia da polimerase (RT-PCR) para o gene da nucleoproteina (N) do RabV, seguido de sequenciamento nucleotidico e analise filogenetica. Sete das 11 amostras a