|SA E SILVA, MARIANA - Former ARS Employee|
|SUSTA, LEONARDO - Former ARS Employee|
Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2015
Publication Date: 7/11/2015
Citation: Sa E Silva, M., Susta, L., Moresco, K.A., Swayne, D.E. 2015. Vaccination of hens decreases virus contamination in eggs after challenge with the virulent Newcastle disease virus (abstract]. In: Convention Notes of the American Veterinary Medical Association Annual Meeting, July 11-14, 2015, Boston, Massachusetts. CDROM.
Technical Abstract: Newcastle disease is an important infectious disease of poultry causing economic losses worldwide. The control is routinely performed by vaccination, however vaccinated birds can shed virus, creating a barrier for trade exports. To determine if vaccination could mitigate these negative outcomes, hens were divided into groups receiving one or two doses of inactivated LaSota vaccine, plus a sham vaccinated group. All groups were challenged with a virulent Newcastle strain (NDV-CA02) 3 weeks after vaccination. Eggs were collected daily and shell, albumin, and yolk were submitted to virus isolation, plus oral and cloacal swabs at 2 and 4 days post challenge (dpc). A second experiment was added to evaluate the distribution of the NDV-CA02 strain at the reproductive tract without vaccination. All the vaccinated birds survived challenge, and the levels of shedding in cloacal swabs decrease significantly when compared to sham birds, as well as oral shedding at 2 dpc for the group vaccinated twice, and 4 dpc for both vaccinated groups. For the second experiment, virus was detected in all segments of oviduct, and minor lesions and viral antigen were observed mainly in the infundibulum. The results of the two experiments show that the challenge virus strain replicates in the reproductive tract of hens, and can possibly contaminate egg components, and that vaccination with LaSota strain significantly decreases the virus contamination of egg components as well as reduced shedding in oral and cloacal swabs in birds challenged with the virulent NDV-CA02.