Title: Vaccination prevents virus contamination inside of eggs laid by newcastle disease virus infected chickens Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2013
Publication Date: August 19, 2013
Citation: Swayne, D.E., Miller, P.J. 2013. Vaccination prevents virus contamination inside of eggs laid by newcastle disease virus infected chickens [abstract]. Book of Abstracts for 18th Congress for World Veterinary Poultry Association, Nantes, France, August 19-23, 2013. p.446. Technical Abstract: Newcastle disease causes a severe systemic disease in chickens with viremia and high mortality. The transmission of Newcastle disease virus (NDV) through the egg has been suggested, but definitive proof of virus passing through the egg is lacking. Furthermore, the role of vaccination to mitigate any egg transmission is unknown. Groups of adult, reproductively-active, White Leghorn chickens (Sham, 1X/LaSota and 2X/LaSota vaccinates) were administered inactivated vaccines and intranasally challenged with virulent NDV and eggs were collected for 14 days post-challenge (DPC). Sham-vaccinated hens died on 4 (n=2), 5 (n=8) and 6 (n=1) DPC while none of the LaSota-vaccinated hens died. Hen egg production during acute phase of disease; i.e. 1-5 DPC, was 51%, 67% and 78% while over the experiment (1-14 DPC), production was 18%, 72% and 75% for Sham, 1X/LaSota and 2X/LaSota groups, respectively. Infected eggs were laid from 2-5 DPC within all groups: Sham, 9 (32%); 1X/LaSota, 4 (13.3% for 1-5 DPC; 4.4% for 1-14 DPC); and 2X/LaSota, 1 (2.1% for 1-5 DPC; 4.4% for 1-14 DPC). With Sham group, virus was present within eggs (10 0.97-4.7 mean embryo infectious doses [EID50]) and on egg shell surface (10 0.97-6.7 EID50), while with LaSota-vaccinated groups, only low levels of virus (10 0.97-1.5 EID50) were found on eggshell surface and not inside the egg. The rate of infected eggs from NDV infected hens was lower than previous studies with high pathogenicity avian influenza virus infection.