Western blot detection of infectious bursal disease virus infection

In order to evaluate the use of a Western blot methodology for the diagnosis of infectious bursal disease virus (IBDV) infection, chickens were experimentally infected with IBDV strains and tested for the presence of viral antigens and antibodies by a blocking Western blot test (bWB). The viral proteins obtained from the bursa of Fabricius (BF) were transferred to a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the chicken sera obtained by heart puncture were used for the detection of these proteins. In order to eliminate nonspecific reactions, we used a rabbit anti-chicken serum (blocking tool). By the use of the bWB test, two distinct viral proteins of 43-kDa (VP2) and 32-kDa (VP3) were detected. We suggest the use of this methodology for the detection of IBDV infection in animals suspected of having IBDV reinfection and a chronic subclinical form of the disease. With the use of the rabbit anti-chicken sera for blocking, this method is practical, sensitive and less time consuming.

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, althought reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination.

Contaminaçäo ambiental pelo rotavírus / Environmental contamination by bovine rotavirus

Com o objetivo de se isolar o rotavírus humano a partir de material fecal diarréico, inoculou-se o material fecal na forma de homogenato previamente descontaminado, em cultura de células MA-104. O material clínico foi estudado pela microscopia eletrônica (ME) e eletroforese em gel de poliacrilamida (EGPA), sendo que, em ambas as técnicas, detectou-se a presença do vírus, de padräo eletroforético humano. Na terceira passagem em cultivo celular foi observado efeito citopático (ECP). O monitoramento da replicaçäo viral foi positivo pelo teste de imunofluorescência (IF). A identificaçäo do isolado através da reaçäo de neutralizaçäo de focos imunofluorescentes (NFIF) e da EGPA revelou a presença de rotavírus bovino. Este trabalho discute as eventuais fontes de contaminaçäo cruzada em nosso laboratório, onde o vírus bovino também é rotineiramente manipulado. A hipótese de o vírus bovino já estar presente no material fecal humano näo pode ser descartada, porquanto näo foi observada qualquer situaçäo que sugerisse presença das duas espécies virais

Acridine orange metachromasia in the cytoplasm of simian rotavirus (SA-11)-infected MA-104 cell cultures

Acridine orange metachromasia was used to determine the distribution of simian rotavirus double-stranded RNA in cultured MA-104 cells 0 to 72 h post-infection. Correlations were made among time of detection and amount of viral antigens, virus yield and the ultrastructural aspects of infected cells. RNAase-resistant cytoplasmic metachromasia appeared 48 h post-infection, 36 h after the initial detection of viral antigens or infectious virions and 24 h after the appearance of the cytopathic effect. Acridine orange staining is thus useful for monitoring the progress of rotaviral infection in cell cultures due to its simplicity and low cost, in spite of its lower sensitivity compared to other techniques evaluated

Detection of astrovirus-like in diarrhoeic stool and its coexistence with rotavirus

É apresentado neste trabalho um caso clínico de diarréia aguda prolongada em uma criança subnutrida e desidratada de 5 meses de idade. O estudo virológico por microscopia eletrônica mostrou que a criança eliminava, pelas fezes aquosas, vírus semelhante, morfologicamente, ao astrovírus e rotavírus. A presença destes vírus foi observada 12 dias após o início da diarréia. A imunomicroscopia eletrônica realizada com o soro da criança mostrou agregados de ambos os vírus. Näo foram detectadas bactérias ou parasitas enteropatogênicos. Os Autores sugerem que este pode ser um caso de infecçäo mista de vírus semelhante ao astrovírus e rotavírus