RESUMO: O trabalho avaliou a atividade antiviral in vitro de própolis e espécies de Baccharis sobre três herpes vírus animais (bovino, equino e suíno). As própolis foram produzidas por duas espécies de abelhas. Pela Apis melifera (abelha africanizada) foram obtidas duas própolis, vermelha e verde, e uma terceira foi obtida pela abelha nativa Tetragonisca angustula (abelha jataí). Os extratos de Baccharis foram obtidos de 4 espécies diferentes: B. oblongifolia, B. burchellii, B. dracunculifolia e B. uncinella. A concentração máxima não tóxica dos extratos foi determinada pela ausência de alterações morfológicas nas células, e essas concentrações então utilizadas nos testes antivirais. A atividade antiviral foi avaliada pela redução do efeito citopático e calculada a partir da diferença entre o título viral do tratado pelo controle e feita a análise estatística. A própolis vermelha foi ativa contra os três herpes vírus, e a própolis verde apresentou inibição contra os herpes vírus equino e suíno, enquanto a própolis da abelha jataí não apresentou atividade antiviral. A maioria dos extratos dos indivíduos masculinos e femininos de todas as espécies de Baccharis apresentou atividade antiviral contra os herpes vírus bovino e suíno. Apenas o extrato do indivíduo feminino de B. oblongifolia foi inibidor contra o herpes vírus equino.

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.

Infectious bursal disease virus (IBDV) is classified according to the antigenicity and virulence into classical virulent (cv), very virulent (vv), and antigenic variant strains. The molecular basis for the IBDV antigenic variation is well established and is associated to the capsid protein, VP2 (gene VP2 of segment A), whereas both VP2 and the RNA-dependent RNA polymerase, VP1 (gene VP1 of segment B), have been correlated with the virulence. In this study, seventeen Brazilian IBDV samples previously characterized by the VP2 gene as cv (three) and vv (fourteen) strains were genetically and molecularly analyzed for their VP1 gene. All of the strains kept with the same cv or vv classification except one sample, Br/03/DR. This sample was classified as vv by its VP2 gene, but it was most closely related to the cv strains by its VP1 partial sequence and phylogeny. Studies on the phylogeny of VP1 have suggested a possible reassortment event that originated the vvVP1. In this case, the sample carrying vvVP2 and cvVP1 could be a descendant of IBDV ancestors prior to the reassortment of vvVP1; alternatively, it could be the result of a genetic exchange between the segments of different strains or with a live attenuated vaccine. Nevertheless, this is the first report of natural genetic reassortment of IBDV in Brazil.

Estudou-se a suscetibilidade de cinco linhagens celulares (IB-RS-2, RK-13, Vero, BHK-21, CER) ao reovírus S1133 e ao virus vacinal (GBV-8) da doença infecciosa bursal de galinha (IBDV). As culturas foram comparadas quanto a presença de efeito citopático (ECP), título viral e detecção de RNA viral. Nas linhagens CER e BHK-21 detectou-se ECP e RNA viral após inoculação com reovírus e na linhagem RK-13 após inoculação com IBDV, com produção de altos títulos virais. Replicação viral com produção de baixos títulos ocorreu nas linhagens IB-RS-2 e Vero inoculadas com o reovírus e na linhagem BHK-21 com IBDV.

The susceptibility of the five cell lines - IB-RS-2, RK-13, Vero, BHK-21, CER - to reovirus S1133 and infectious bursal disease virus (IBDV vaccine GBV-8 strain) was studied to better define satisfactory and sensitive cell culture systems. Cultures were compared for presence of CPE, virus titers and detection of viral RNA. CPE and viral RNA were detected in CER and BHK-21 cells after reovirus inoculation and in RK-13 cell line after IBDV inoculation and with high virus titers. Virus replication by production of low virus titers occurred in IB-RS-2 and Vero cells with reovirus and in BHK-21 cell line with IBDV.