|SA E SILVA, MARIANA - Former ARS Employee|
|MORESCO, KIRA - Former ARS Employee|
|BERTRAN, KATERI - Consultant|
|JACKWOOD, DARAL - The Ohio State University|
Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2016
Publication Date: 9/13/2016
Citation: Sa E Silva, M., Moresco, K., Bertran, K., Jackwood, D., Swayne, D.E. 2016. Infection with some infectious bursal disease virus pathotypes produces virus in chicken muscle tissue and the role of humoral immunity as a mitigation strategy. Avian Diseases. 60(4):758-764.
Interpretive Summary: Infectious bursal disease virus (IBDV) causes an important disease to the chicken industries and impacts trade in chicken meat. This study determined viable IBDV could only be isolated from breast and/or thigh meat of broiler chickens infected by the two most virulent strains. In a second experiment, birds were vaccinated according to a commercially used vaccination program for IBDV, and challenged after vaccination to evaluate the role of vaccination in decreasing the presence of virus in the meat. The vaccination protocol used in the study has shown to be efficient in decreasing the already low presence of virus in chicken meat.
Technical Abstract: Infectious bursal disease virus (IBDV) causes important economic losses to the chicken industries worldwide and impacts chicken meat trade in countries with self-declared freedom. The aim of this study was to determine the frequency and titers of IBDV in primary lymphoid tissues and meat of infected broilers, and the role of vaccination as a mitigation strategy. In Experiment 1, broiler-type specific-pathogen-free (SPF) chickens were challenged with STC (serotype 1, classical [cIBDV]), Indiana (serotype 1, variant [varIBDV]), rA (serotype 1, very virulent [vvIBDV]), and Ohio (serotype 2, avirulent [aIBDV]) IBDV strains. Clinical signs or mortality were observed only in cIBDV group, where 2 out of 18 birds died (10 and 12 days post-inoculation). Infection was confirmed in all chickens within the four pathotype groups by virus isolation from cloacal bursa and thymus or seroconversion. However, virus was only isolated in low titers from a few breast and/or thigh meat samples, and only from cIBDV and vvIBDV-infected chickens. In Experiment 2, three groups were used: a) 1 day-of-age (doa) maternal antibody positive (MAb+) broiler-type SPF chickens vaccinated with herpes virus of turkeys (HVT)-IBDV recombinant vaccine (Vaxxitek®, Merial) (MAb+/Vax), or b) not vaccinated (MAb+/No-vax), and c) maternal antibody negative, not vaccinated chickens (MAb-/No-vax). All chickens were challenged at 21 doa with varIBDV or vvIBDV. MAb+/Vax and MAb+/No-vax chickens had significantly lower virus titers in primary lymphoid tissues compared to MAb-/No-vax chickens. No virus was detected in meat from any of the groups challenged with varIBDV, and only a few minimal virus positive meat samples were detected in MAb+/Vax or MAb+/No-vax groups challenged with vvIBDV. This study indicates that only cIBDV and vvIBDV rA strain can be found in meat at low levels and that the vaccination protocol currently used in the U.S.A. was an effective mitigation strategy for vvIBDV challenged birds.