First molecular detection of co-infection of honey bee viruses in asymptomatic Bombus atratus in South America / Primeira detecção molecular de co-infecção de vírus de abelhas em Bombus atratus assintomática na América do Sul

Pollination is critical for food production and has the particularity of linking natural ecosystems with agricultural production systems. Recently, losses of bumblebee species have been reported worldwide. In this study, samples from a commercial exploitation of bumblebees of Argentina with a recent history of deaths were studied using a multiplex PCR for the detection of the honey bee viruses most frequently detected in South America. All samples analysed were positive for co-infections with Deformed wing virus, Black queen cell virus and Sacbrood virus. This is the first report of infection of Bombus atratus with honey bee viruses. A better understanding of viral infections in bumblebees and of the epidemiology of viruses could be of great importance as bumblebees can serve as possible viral reservoirs, resulting in pathogen spillover towards honey bees and native bumblebees.

A polinização é essencial para a produção de alimentos e tem como particularidade a conexão entre os ecossistemas naturais com sistemas de produção agrícola. Recentemente, as perdas de espécies de bumblebee em todo o mundo têm sido relatadas. Neste trabalho, amostras de uma exploração comercial de bumblebee da Argentina, com recente história de mortes foram estudadas utilizando uma Multiplex PCR para a detecção de vírus de abelha mais frequentemente detectados na América do Sul. Todas as amostras analisadas foram positivas para as co-infecções com Deformed wing virus, Black queen cell viruses e Sacbrood virus. Este trabalho descreve o primeiro relato de infecção de Bombus atratus com vírus de abelhas. Uma melhor compreensão das infecções virais em bumblebee e da epidemiologia dos vírus poderia ser de grande importância, uma vez que tais abelhas podem servir como reservatório viral, com possível repercussão tanto na produtividade de abelhas melíferas como afetando-as diretamente.

Feline immunodeficiency virus infection: a comparative study of different diagnostic techniques

Avaliou-se a técnica de imunofluorescência indireta (IFA) na detecção de anticorpos contra o vírus da imunodeficiência felina (FIV) numa pesquisa epidemiológica do FIV na Argentina. A IFA foi modificada e comparada com duas outras técnicas imunológicas: western blot (WB) e imunocromatografia em camadas (SI) com kit comercial e também com reação em cadeia de polimerase (PCR) para detecção do DNA proviral. A IFA mostrou ser um teste com alta sensibilidade e especificidade e poderá ser empregada como ferramenta útil em estudos epidemiológicos. A baixa porcentagem de reatividade não específica pode ser esclarecida com testes mais avançados ou usando métodos alternativos.

Rapid diagnosis of pseudorabies virus infection in swine tissues using the polymerase chain reaction (PCR)

In Argentina pseudorabies is an endemic disease. Routine diagnosis is made by virus isolation. It is a very long procedure to carry out and gives variable results depending on the quality of sample, hence the need for effective techniques, which are rapid and not dependent on the isolation of infectious virus. The polymerase chain reaction (PCR) technique has provided a sensitive, specific and rapid mean to detect DNA sequences. This study describes a PCR method for detection of pseudorabies virus sequences in swine tissues. In order to determine the presence of suid herpesvirus-1 DNA and antigens, 36 tissue samples collected from 19 dead pigs, with signs of pseudorabies infection, were examined by PCR, virus isolation and indirect immunofluorescence, respectively. Fifteen out of 19 pigs were positive at least for one tissue by PCR (15/19) while only three pseudorabies virus strains were isolated (3/19). All the amplified products were identified by digestion with Sa/l and hybridization. The method described herein circumvents tedious viral isolation and DNA purification and would be a valuable tool for rapid diagnosis, since it would take less than 5 h to reach an accurate result even in poorly preserved tissue samples.

ELISA indirecto para el diagnóstico rápido de Influenza Equina / Indirect ELISA for the rapid diagnosis of Equine Influenza

An indirect enzyme linked immunosorbent assay was developed. Infected and non infected allantoic fluids precipitated with polyetilenglycol 6000 were used as antigen and control antigen, respectively. Serum samples were diluted 1/20 and a commercial horse radish peroxidase-labelled rabbit anti-equine IgG was used as second antibody. The reaction was developed using azino-diethylbenzotyazol-sulfonate (ABTS). Cut-off was determined by ratio sample (Rs). The hemagglutination inhibition test was used as a reference test for the 391 samples analyzed. Of these, 301 sera were positive by hemagglutination inhibition test and indirect ELISA, 75 were negative by both techniques, and 15 were positive by indirect ELISA and negative by hemagglutination inhibition test. Using hemagglutination inhibition test as standard, the indirect ELISA showed a relative specificity and sensitivity of 83.3 and 100, respectively. This indirect ELISA is useful as screening test.