Validation of egg yolk antibody based C-ELISA for avian influenza surveillance in breeder duck.
Active surveillance for avian influenza virus (AIV) has expanded from chicken to various poultry species including duck. To further effective antibody screening in laying breeder ducks, we validated the egg yolk antibody as alternative source to serum for AIV antibody. Sera and eggs were collected at weekly intervals after two types of AIV vaccination, H5N3 and H9N2. The antibody levels were determined by an agar gel immunodiffusion (AGID) test, haemagglutination inhibition (HI) test and the competitive enzyme-linked immunosorbent assay (C-ELISA). AGID test did not detect antibodies in egg yolk, and the agreement between AGID test and either HI test or C-ELISA in serum was slight and fair based on kappa statistics (kappa value (kappa)< or =0.19 in H5N3 group and kappa< or =0.37 in H9N2 groups). However, there was almost perfect agreement between HI test and C-ELISA (kappa>0.9 in all group). The C-ELISA was as sensitive and specific as the HI test, and could be used as a pre-screening test for the detection of type A avian influenza virus antibody. Comparison was made between egg yolk and serum antibody titers by a regression analysis. A high correlation was observed between serum and yolk antibody titers (r=0.8762 for H5N3 and 0.8914 for H9N2 in HI test; r=1 for H5N3 and 0.9686 for H9N2 in ELISA test), although egg yolk antibodies were detected later and remained lower levels than serum antibodies. In field trials involving 54 duck flocks, the positive rate of egg yolk and serum samples showed agreement for the detection of AIV antibody. We concluded that as an alternative to serum, antibody monitoring of laying breeder duck using egg yolk with C-ELISA is feasible and is recommended.
Jeong
Ok-Mi
OM
National Veterinary Research and Quarantine Service, Anyang-6-dong, Manangu, Anyang-city, Gyeonggi-do 430-824, Republic of Korea.
Kim
Min-Chul
MC
Kang
Hyun-Mi
HM
Ha
Gun-Woo
GW
Oh
Jin-Sik
JS
Yoo
Jung-Eun
JE
Park
Chan-Hee
CH
Kwon
Ji-Sun
JS
Pack
Mi-Ra
MR
Kim
Hye-Ryoung
HR
Kim
Yong-Joo
YJ
Kwon
Jun-Hun
JH
Lee
Youn-Jeong
YJ
D000818:Animals; D000914:Antibodies, Viral; D004372:Ducks; D004530:Egg Yolk / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D007252:Influenza Vaccines / Q000276:immunology; D005585:Influenza in Birds / Q000175:diagnosis* / Q000276:immunology / Q000517:prevention & control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012698:Serologic Tests
D000914:Antibodies, Viral; D007252:Influenza Vaccines