Characterization of Humoral Immune Response from Commercial Poultry Flocks Vaccinated Against Avian Encephalomyelitis Virus

C, Prior KS, Pires P. GV, PeripolliDiogenes, Dezen

Despite the massive use of vaccines against Avian encephalomyelitis virus (AEV), outbreaks of the disease that may be associated with low flock immunity are still reported. This study aimed to characterize the serological immune response of birds vaccinated against AEV under field conditions. For this, a database comprising 65,535 bird serum samples collected from 2015 to 2019 and tested for antibodies against AEV, was analyzed. Samples were stratified by the following parameters: type of flock, age of birds, year of sample collection, geographic origin, layers production cycle, and were correlated with the presence or absence of antibodies anti-AEV. Broilers showed a higher percentage of samples without anti-AEV antibodies than breeders or broiler grandparents. The year and origin of the samples also showed differences in bird immunization levels, which demonstrates variation in vaccination management. Despite the influence of factors associated with vaccine failures, the intrinsic characteristics of each flock may lead to the detection of different humoral responses, which reinforces the importance of serological monitoring for AEV as a disease control strategy.(AU)

1. broiler
2. immunization failure
3. Antibody
4. serology