Block Hermann, Meyer-Block Karen, Rebeski Dierk E, Scharr Heike, de Wit Sjaak, Rohn Karl, Rautenschlein Silke
Poultry Practice Meyer-Block, Uelsen, Germany.
Avian Pathol. 2007 Oct;36(5):401-9. doi: 10.1080/03079450701589175.
The right strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level and variation in maternally derived IBD antibodies, and the IBD vaccine strains to be used. Usually, standard vaccination programmes are used, which are not always adapted to the specific conditions on the farm and to the immune status of chickens. Employing the "Deventer formula" may help to estimate the optimal time for vaccination for a specific flock based on the maternally derived antibody level, its variation, the genetic background of the chicken, and the IBD vaccine strain. Two field studies with 16 or 20 commercial broiler flocks were conducted, applying an intermediate IBD vaccine before, at the best, and after the estimated optimal vaccination time estimated by the "Deventer formula". These studies showed that flocks IBD-vaccinated between 1 day before, at, or up to 3 days after the estimated optimal time point developed detectable humoral immunity up to 14 days post vaccination. If birds had been vaccinated more than 1 day before the calculated optimal vaccination date, the humoral immune response was delayed or non-detectable until slaughter. The induction of humoral immunity correlated with the incidence of bursa lesions and IBDV detection by reverse transcriptase-polymerase chain reaction. As indicated in this study, under field conditions bursa lesions may develop later than predicted based on experimental experiences. The late incidence of bursa lesions after vaccination may be confused with field virus-induced lesions, in which case sequencing may offer a valuable tool for differentiation.
传染性法氏囊病（IBD）防控的正确策略及其在田间条件下的成功率取决于卫生管理、IBD田间压力、母源IBD抗体的水平和变化，以及所使用的IBD疫苗毒株。通常采用标准的疫苗接种程序，但这些程序并不总是能适应农场的具体条件和鸡的免疫状况。采用“代芬特尔公式”可能有助于根据母源抗体水平、其变化、鸡的遗传背景和IBD疫苗毒株来估计特定鸡群的最佳接种时间。进行了两项分别针对16个或20个商业肉鸡群的田间研究，在根据“代芬特尔公式”估计的最佳接种时间之前、最佳时间以及之后接种一种中等毒力的IBD疫苗。这些研究表明，在估计的最佳时间点前1天、最佳时间点或最佳时间点后3天内接种IBD疫苗的鸡群，在接种后14天内可产生可检测到的体液免疫。如果在计算出的最佳接种日期前1天以上接种，体液免疫反应会延迟，直到屠宰时仍检测不到。体液免疫的诱导与法氏囊病变的发生率以及通过逆转录聚合酶链反应检测到的IBDV相关。如本研究所示，在田间条件下，法氏囊病变可能比基于实验经验预测的时间出现得更晚。接种疫苗后法氏囊病变的后期发生可能与野外病毒引起的病变相混淆，在这种情况下，测序可能是一种有价值的鉴别工具。
