Caracterização antigênica e molecular de oito amostras do vírus da doença de Aujeszky isoladas no estado do Rio Grande do Sul em 2003

In vitro antiviral activity of propolis and Baccharis sp. extracts on animal herpesviruses

ABSTRACT: This study evaluated the in vitro antiviral activity of propolis and Baccharis sp. extracts on three animal herpesviruses (bovine, equine and swine). The propolis samples were produced by two species of bees. There was red and green propolis, which came from africanized Apis melifera, and a third type obtained from a native bee species, Tetragonisca angustula (jatai). The Baccharis extracts were obtained from four different species: B. oblongifolia, B. burchellii, B. dracunculifolia and B. uncinella. The maximum non-toxic concentration of the extracts was determined when no visible morphological changes were observed on the cells. These non-toxic concentrations were used in the antiviral tests. Antiviral activity was evaluated using a reduction assay of the cytopathic effect, which calculated the difference between treated and control virus titer by statistical analysis. Red propolis was active against the three herpesviruses and green propolis showed inhibition against the equine and swine herpesviruses. Conversely, jataí propolis showed no antiviral activity. Most extracts coming from male and female individuals of all of the Baccharis species showed antiviral activity against bovine and swine herpesviruses. Only the extract of the female specimen of B. oblongifolia was an inhibitor against equine herpesvirus.

Genotyping of the pseudorabies virus by multiplex PCR followed by restriction enzyme analysis

Suid herpesvirus 1 (SuHV-1) is the causative agent of Aujeszky's disease. The infectious agent has only one serotype, but it was classified by restriction enzyme analysis of the whole genome into four genotypes, named I to IV. The aim of this study was to standardize a rapid method for genotyping SuHV-1 without virus isolation, using a multiplex-PCR followed by enzymatic restriction analysis. The complete genome of the virus was analyzed in silico to determine the restriction sites for the enzyme BamHI. Primers were designed to flank sites with emphasis on certain points of differentiation of genotypes. The standard PCRs were able to detect the SuHV-1 and also to differentiate genotypes from brain tissue of infected pigs. The BamHI-PCR is a rapid, practical, and sensitive way to genotype SuHV-1.

Molecular epidemiology of Brazilian pseudorabies viral isolates

Pseudorabies is a disease caused by pseudorabies virus (PRV) and is responsible for considerable economic losses in the swine industry. The objective of this work was to use molecular epidemiology as a tool to facilitate the study of PRV outbreaks in Brazil. The standard PRV strain Shope, the vaccine strain Bartha and isolates from the south and the southeast regions of Brazil, were amplified for gE and gC partial genes by PCR. Results indicated that Brazilian PRV isolates are grouped in two clusters, A and B, except for one isolate that grouped with Bartha and Shope. Most Brazilian PRV isolates belonged to cluster B and diverged from virus isolated from other countries.

Epidemiologia e controle dos focos da doença de Aujeszky no Rio Grande do Sul, em 2003

A doença de Aujeszky (DA), ou pseudo-raiva, é uma enfermidade infecto-contagiosa de etiologia viral de grande importância para a suinocultura comercial em todo o mundo. A infecção causa perdas econômicas diretas e indiretas, pela restrição ao comércio internacional de produtos suínos. Embora a DA venha sendo notificada em várias regiões do Brasil desde o início do século XX, o Rio Grande do Sul (RS) permanecia "provisoriamente livre" com base em critérios da Organização Internacional de Epizootias (OIE). Em 2003 ocorreram dois focos da enfermidade em municípios do norte do RS, limítrofes com Santa Catarina, Estado que tem registrado vários focos nos últimos anos. Como estratégia de combate foram determinados o rastreamento da movimentação de suínos, a interdição da área e a erradicação dos focos através de abate sanitário em matadouros sob Inspeção Federal. No evento 1 (Pinheirinho do Vale, janeiro de 2003) cinco unidades produtoras de leitões (UPLs) foram afetadas, sendo que uma apresentou animais com sinais clínicos. A partir desse foco foram rastreados 42.399 suínos em 146 rebanhos, sendo eliminados seis rebanhos - o foco índice e cinco outras com sorologia positiva - num total de 7.822 animais. No evento 2 (Aratiba, setembro de 2003), a disseminação da infecção foi maior, atingindo outros três municípios e 77 granjas (nove com sinais clínicos, 68 com sorologia positiva). Foram rastreados 109.316 suínos em 630 rebanhos, com a erradicação de 28.443 animais das granjas que apresentaram sinais clínicos ou sorologia positiva. No total foram rastreados 151.715 animais em 776 rebanhos, sendo detectados 71 rebanhos com sorologia positiva. Essas medidas foram eficazes na erradicação dos focos e impediram a disseminação da enfermidade para outras regiões, permitindo ao RS readquirir o status sanitário anterior aos surtos.