RESUMO
Analysis of 476 faecal samples from diarrhoeic piglets was performed using electron microscopy (EM) and a competitive blocking (CB)-ELISA based on monoclonal antibodies to the VP6 protein of group A rotavirus. Rotavirus was detected by EM and/or CB-ELISA in 111 (23.3%) samples. Of these, all groups of rotavirus were identified in 83 (74.8%) samples by EM (EM+), while group A rotavirus was identified in 90 (81.1%) samples by CB-ELISA (ELISA+). However, only 62 (55.9%) of samples were positive using both detection methods. The finding of 28 (25.2%) EM-/CB-ELISA+ samples illustrated the high sensitivity of the CB-ELISA method. On PCR analysis, groups B and C rotavirus was found in 3 and 16 of 19 EM+/CB-ELISA- samples, respectively. Although the study illustrates the high sensitivity of a CB-ELISA in rotavirus detection, the findings highlight the need to use a range of diagnostic methods in detecting these viruses in clinical samples.
Assuntos
Ensaio de Imunoadsorção Enzimática/veterinária , Fezes/virologia , Microscopia Eletrônica/veterinária , Infecções por Rotavirus/veterinária , Rotavirus/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Diarreia/veterinária , Diarreia/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Microscopia Eletrônica/métodos , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/virologia , Sensibilidade e Especificidade , Suínos , Doenças dos Suínos/diagnósticoRESUMO
Astroviral infection has been described as one of the causes of porcine diarrhoeal disease. Here we describe the detection of astrovirus-like particles by electron microscopy in a diarrhoeal specimen. Furthermore, a cytopathic virus was isolated and propagated in an established porcine kidney cell line, PK-15. Reverse transcription and PCR performed with astrovirus-specific primers amplified a product with the expected size. Sequencing of the PCR product revealed that the virus observed by electron microscopy and propagated in the porcine cell line is an astrovirus, showing 86% identity at the nucleotide level with the only known porcine astrovirus, PAstV. Phylogenetic analysis clustered the novel isolate, Sb4685, together with PAstV in a broad clade comprising mammalian astroviruses.