Infectious bursal disease virus (IBDV) is responsible for a highly contagious disease of poultry causing severe immunosuppression in chickens. A double antibody sandwich ELISA (DAS-ELISA) was developed to detect IBDV from clinical samples. Two kinds of anti-IBDV antibodies, monoclonal antibody R63 and chicken anti-IBDV sera, were used for DAS-ELISA. Detection limit of IBDV by DAS-ELISA was approximately 10 2.7 EID 50 /ml. The DAS-ELISA detected IBDV from most (13/14) of vaccine products including mild, intermediate and intermediate-plus types. The DAS-ELISA also detected IBDV from all (19/19) of field Korean isolates including very virulent and intermediate-plus phenotypes. Our results indicate that the DAS-ELISA would provide useful diagnostic tool to detect IBDV from clinical samples as well as rapid quantitative detection of IBDV.
Surveillance and diagnosis of avian metapneumovirus (AMPV) infection typically involve measurement of serum antibodies. In the current study, eggs instead of serum samples were used for the detection of AMPV antibodies in egg-laying chicken hens by enzyme-linked immunosorbent assay (ELISA). AMPV-free commercial layer hens were experimentally challenged with AMPV strain SC1509 through intravenous or oculonasal administration. Antibody levels were determined by ELISA. AMPV antibodies were detected in egg yolks from challenged hens by 7 days postinoculation (dpi), with the peak titer at 16 dpi. Antibody levels in eggs laid at 28 dpi correlated well (r = 0.93) with sera taken 28 dpi from the same hens. In a field trial of the yolk ELISA, six broiler breeder farms were surveyed, and all tested positive for AMPV antibodies in hen eggs, although positivity varied from farm to farm. Abnormal discolored eggs collected from outbreak farms had significantly higher titers of AMPV yolk antibodies than normal eggs from the same farm, unlike clinically healthy farms, where normal and abnormal eggs had similar antibody titers. These results indicate that diagnosis of AMPV infection by yolk ELISA to detect anti-AMPV antibodies may be a suitable alternative to serologic testing.
To expand the epidemiological understanding of Newcastle disease in Jeju Province, Korea, active surveillance was extensively performed through a virological examination for poultry farms and wild birds in Jeju Province during 2007~2008. Samples (swabs or fresh feces) were collected from a total of 6,485 birds including 6,405 domestic birds (chickens, ducks, pheasants, geese, quails, turkeys, and ostriches) and 80 wild birds. A total of 24 hemagglutinating agents were isolated from domestic birds on fourteen farms including five Korean native chicken, one layer chicken, two broiler chicken, four duck and two pheasant farms. The hemagglutinating agents were all identified as lentogenic NDV based on the reverse transcriptase polymerase chain reaction, sequence analysis of amino acids on the F cleavage site and mean death time in chicken embryos. The F gene-based phylogenetic analysis revealed that the NDV isolates were classified into genotypes 1 or 2 of class II. These lentogenic viruses were closely related to NDV vaccine strains used in Jeju Province. Active surveillance conducted for Newcastle disease indicates no scientific evidence of virulent NDV infection in chickens in Jeju Province, Korea since 2005.
Avian metapneumovirus (AMPV) is an emerging pathogen causing respiratory and reproductive illness in poultry worldwide. To demonstrate the presence of AMPV in domestic chickens in Korea, we attempted to isolate AMPV from affected chickens. A cytopathic agent was isolated using chicken tracheal ring culture from dead chickens from a broiler breeder farm with reduced egg production in Korea. This agent, termed SC1509 strain, subsequently passed in Vero cells with distinct cytopathic effects. The SC1509 strain was confirmed as avian metapneumovirus (AMPV) using both RT-PCR test and monoclonal antibody-based immunofluorescence assay. Sequence analysis based on the G glycoprotein revealed that the SC1509 strain had 22.5 to 96.0% nucleotide sequence identity and 11.1 to 92.7% predicted amino acid sequence identity with previously published AMPV strains, particularly with the highest sequence homology (95.8 to 96% for nucleotides and 92.2 to 92.7% for amino acids) to European strains belonging to genotype B. The SC1509 strain was phylogenetically clustered with genotype B viruses, confirming that the SC1509 strain belongs to genotype B. This is the first report of genotype B avian metapneumovirus from chickens in Korea.
Infectious bursal disease virus (IBDV) causes a highly contagious and immunosuppressive disease of chicken. Agar gel immunodiffusion using IBDV antigen extracted from bursa of Fabricius of infected chicken has been used officially for diagnosis of IBDV in Korea. In this study, in order to replace the IBDV whole virus antigen with non-infectious antigen, recombinant VP2 protein (rVP2) of IBDV was produced using recombinant baculovirus expression system. Purified baculovirus-expressed rVP2 was used as an antigen in an agar gel immunodiffusion (AGID). rVP2 antigen precipitated specifically IBDV antibodies. AGID using rVP2 antigen detected anti-IBDV antibodies from 6 dpi to 28 dpi (termination of the experiment) when specific pathogen free chickens were experimentally infected with IBDV 52/70 strain. This was consistent with result by AGID using IBDV antigen, virus neutralization test (VNT) and a commercial ELISA kit (except for one serum). The sensitivity of rVP2 was the same with that of IBDV antigen when field sera (n=324) were tested by AGID. However, AGID using rVP2 antigen detected maternal antibodies from broiler chickens (n=20) on a broiler farm up to 15 days old, although the detection rate of the AGID was relatively low compared to a commercial ELISA kit. Our results indicate that IBDV whole virus antigen from IBDV infected chickens would be replaced with recombinant VP2 protein as an antigen for AGID.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.