Comparison Methods Detecting Newcastle Disease Virus Of Chicken

A combination of traditional viral isolation and sandwich ELISA method was applied to detect newcastle disease virus of chicken. This approach was compared with traditional diagnostic method in two experiments.In experiment 1, cloacal swab specimens from vaccinated chicken flock were passed once in 10-day-old SPF embryonated chicken eggs. The allantoic fluid was harvested from 24h to 96h post-innoculation. The sandwich ELISA based on monoclonal antibodies was applied to detect Newcastle disease virus using the allantoic fluid harvested. Traditional diagnostic methods recommended by OIE confirmed the NDV viruses. The results showed that there were 453 positive samples, 2959 negative samples and 11 suspicious samples of total 3423 samples detected. The coincidence rate of positive samples was 99.3 and that of negative ones was 99.7%. Further virulence identification indicated that the velogenic, mesogenic or lentogenic NDV strains existed in these positive samples. Thus, this method to detect of Newcastle disease virus is proved to be more rapid and more accurate as compared with other methods. Positive specimens detected were not all infected by virulent viruses, or might be infected by mesogenic or lentogenic NDV strains.In experiment 2, cloacal swab specimens from vaccinated chicken flock were propagated once by SPF embryonated chicken eggs, and then the NDV (Newcastle disease virus) detection of the harvested allantoic fluid was carried out by the sandwich ELISA. The results showed that this method had good specificity, with high detectable rate of positive NDV samples, without interference from AIV. Detecting 453 positive samples and 2959 negative samples with this method and the traditional diagnostic methods recommended by OIE showed that the coincidence rate of positive...