Genetic characterization of rabies virus isolated from bovines and equines between 2007 and 2008, in the States of São Paulo and Minas Gerais / Caracterização genética de vírus da raiva isolado de bovinos e equinos entre 2007 e 2008, nos Estados de São Paulo e Minas Gerais

INTRODUCTION: Rabies is an acute disease of the central nervous system and is responsible for the deaths of thousands of humans, wild animals and livestock, particularly cattle, as well as causing major economic losses. This study describes the genetic characterization of rabies virus variants that circulate in Desmodus rotundus populations and are transmitted to herbivores. METHODS: Fifty rabies virus isolates from bovines and equines in the States of São Paulo and Minas Gerais, Brazil, were genetically characterized and compared with sequences retrieved from GenBank. RESULTS: Two clusters (I and II) with mean nucleotide identities of 99.1 and 97.6 percent were found. The first of these contained nearly all the samples analyzed. Lineages from other Brazilian states grouped in cluster II. CONCLUSIONS: Analysis of the amino acid sequences of the N proteins revealed the existence of genetic markers that may indicate possible variations between geographic regions, although the biologically active regions are conserved within the species over space and time.

INTRODUÇÃO: A raiva é uma doença aguda do sistema nervoso central e é responsável por mortes de milhares de humanos, animais silvestres e animais de criação - especialmente bovinos - além de causar elevadas perdas econômicas. Este trabalho descreve a caracterização genética das variantes do vírus da raiva que circulam em populações de Desmodus rotundus e são transmitidas aos herbívoros. MÉTODOS: Cinquenta isolados de vírus da raiva de bovinos e equinos provenientes dos Estados de São Paulo e Minas Gerais, Brasil, foram caracterizadas geneticamente e comparadas com sequências recuperadas do GenBank. RESULTADOS: Dois clusters, I e II, apresentando identidades médias de nucleotídeos de 99,1 e 97,6 por cento, foram obtidos, sendo o primeiro composto de quase a totalidade das amostras analisadas. Linhagens de outros estados do Brasil "clustered" no II. CONCLUSÕES: A análise das sequências de aminoácidos da proteína N revelou que existem marcadores genéticos que podem determinar uma possível regionalidade embora as regiões biologicamente ativas apresentem-se conservadas dentro das espécies ao longo do tempo e espaço.

G and P rotavirus genotypes in stool samples from children in Teresina, State of Piauí

A total of 123 stool specimens collected in Teresina, Piauí between 1994 and 1996, from 0 to 2-year-old children with diarrhea, were used for this study. Molecular characterization of the G and P rotavirus genotypes was performed using the reverse transcriptase polymerase chain reaction. The following results were obtained for the P genotypes: P[8] (17. 1 percent), P[1] (4. 9 percent), P[4] (3. 3 percent), P[6, M37] (2. 4 percent) and mixtures (27. 6 percent). The P[1]+P[8] mixture was found in 19. 5 percent of the samples. For the G genotypes, the results were: G1 (25. 2 percent), G5 (13. 8 percent), G2 (2. 5 percent), G4 (2. 5 percent), G9 (0. 8 percent) and mixtures (41. 5 percent). G1+G5 was the mixture most frequently found (12. 1 percent). Our results showed unusual combinations such as P[1]G5 and P[1]+P[8]G5. The high percentage of mixtures and unusual combinations containing mixtures of human and animal rotavirus genotypes strongly suggests the possibility of gene reassortment and interspecies transmission.

Um total de 123 amostras fecais de crianças de 0 a 2 anos com diarréia, coletadas em Teresina, Piauí, entre 1994 e 1996 foi utilizada neste estudo. Para a caracterização molecular dos genótipos G e P de rotavírus, foram realizadas as reações de transcriptase reversa e reação em cadeia pela polimerase. Os seguintes resultados foram obtidos para o genótipo P: P[8] (17,1 por cento), P[1] (4,9 por cento), P[4] (3,3 por cento), P[6, M37] (2,4 por cento) e misturas (27,6 por cento). A mistura P[1]+P[8] foi encontrada em 19,5 por cento das amostras. Para o genótipo G os resultados foram: G1 (25,2 por cento), G5 (13,8 por cento), G2 (2,5 por cento), G4 (2,5 por cento), G9 (0,8 por cento) e misturas (41,5 por cento). A mistura G1+G5 foi a mais freqüentemente encontrada (12,1 por cento). Nossos resultados mostram combinações não usuais como P[1]G5 e P[1]+P[8]G5. A alta porcentagem de misturas e as combinações não usuais contendo misturas de genótipos de rotavirus humanos e animais sugerem fortemente a possibilidade de rearranjo genético e transmissão interspecies.

Short-interfering RNAs as antivirals against rabies

This study aimed to test in vitro a RNA-interference based antiviral approach for rabies with short-interfering RNAs (siRNAs) against rabies virus nucleoprotein mRNA. BHK-21 cells were infected with serial dilutions of PV rabies virus strain and transfected with a pool of three siRNAs. Direct immunofluorescence staining showed a 5-time decrease in virus titer when compared to a non-treated plate, showing a promising new approach to the development of antivirals for rabies treatment.

Diagnosis of human rabies cases by polymerase chain reaction of neck-skin samples

Rapid diagnosis of rabies in suspected human cases influences post-exposure prophylaxis for potential contacts of the patient and ensures appropriate patient management. Apart from the central nervous system (CNS), rabies virus (RABV) is usually present in small sensory nerves adjacent to hair follicles of infected humans. We used an RT-PCR, with primers targeted to the 3' terminal portion of the nucleoprotein gene (N), to test neck-skin samples of nine patients who had rabies in order to validate a diagnostic method that could serve as an additional tool for rabies diagnosis, particularly in antemortem samples. Six of eight postmortem samples were found to be positive for rabies by RT-PCR, and one of two samples collected antemortem was positive with this same technique. Results were confirmed by DNA sequencing; this validates RT-PCR and neck-skin as a suitable technique and type of sample, respectively, for use in the diagnosis of human rabies. RT-PCR applied to neck-skin biopsies could allow early diagnosis and lead to more effective rabies treatment.